Shock reduction using ATP as 1st line therapy for spontaneous sustained ventricular tachycardia in patients with ischemic dilated cardiomyopathy and severly depressed ventricular function

Authors: Stefano Nardi MD, PhD (*), Luigi Argenziano MD, PhD (*)
(*) Arrhythmia, Electrophysiologic Center and Cardiac Pacing Unit, Thoracic Surgery and Cardiovascular Department, Presidio Ospedaliero Pineta Grande, Castel Volturno (CE), Italy (I)


Implantable cardioverter-defibrillators (ICDs) have clearly demonstrated to terminate an elevated percentage of sustained ventricular tachycardia (SVTs), both with shock therapy and, painlessly, with antitachycardia pacing (ATP). The purpose of this study was to investigate the efficacy and safety of ATP as 1st line therapy for terminating SVTs, occurring in patients (pts) with coronary artery disease (CAD) and severely depressed left ventricular ejection fraction (LVEF) due to not reversible causes, comparing this approach with shock.


Figure 1: Rationale for ATP Rx is that a “WAVE-FRONT” critically temporized with VTCL and applied proximal to the “Slow Conduction Zone” is able to capture the CIRCUIT, then interrupt the reentry


From March 2004 through June 2013, 408 consecutive patients (pts) were considered eligible for this study, according with MADIT and/or SCD-HeFT criteria, and 387 of them (94,8%) accepted and underwent ICD implant. Pts were randomly assigned to ATP group (190/387) or shock group (197/387) and three zone of detection were assigned in all pts: a slow VTs window (320-400 msec), a fast VTs window (240-320 msec), and a ventricular fibrillation (VF) window (<320 msec). In ATP group, 3 burst sequence were programmed in slow VT zone and 1 burst sequence was programmed in fast VTs zone (burst sequences of 8-10 pulses at 88% CL) before shock, respectively, whereas in shock group (87/169) shock was adopted as 1st line therapy for all SVTs. No statistically differences, in term of age (72,2 vs 73,4, p=NS), sex (man 73,1% vs 69,3%, p=NS), NYHA functional class (2,8 vs 2,6, p=NS), LVEF (24,5% vs 26,9%) and drugs therapy were observed between two groups. Based on the evaluation of stored electrograms (EGMs), we aimed to prospectively follow pts and to analyze these two different therapeutic approach.


Figure 2: ATP programmability with adaptative cycle length


A total of 3,288 spontaneous VTs episodes occurred in 171 pts (41,9%) during a mean follow-up of 54,4±23,1 months (90 pts in ATP group and 81 pts in shock group). Among these, 2,235/3,288 (67,9%) were SVTs and 612 of them (27,4%) were detected in VF zone, and then treated with primary shock delivery, whereas in the remaining 1,623 of them (72,6%), 936 episodes occurred in ATP group (57,6%) and 687 episodes occurred in shock group (42,4%). In ATP group, ATP was able to terminate successfully 80,7% of SVTs, failed in 9,3% of SVTs, finally reverted by shocks, and in 10% of SVTs ATP was able to converted arrhythmias in a slower VT, outside the VT zone. 61% of these slower SVTs were self-terminating whereas 39% were redetected and treated. Finally, in primary intention-to-treat basis, ATP was successful in 834/936 SVTs (89%) and unsuccessful in 102/936 SVTs (11%). In contrast, 657/687 (95,6%) of all SVTs episode detected in VT zone and that occur in shock group were shock terminated, whereas 30/657 (4,4%) were accelerated into VF zone. The individual termination rate and acceleration rate per pt were comparable in both groups, as well as mean time of SVT termination (ATP=12.6 sec vs Shock=10.9 sec, p=NS).


Figure 4: Results of a registry comparing ATP vs shock therapy as primary choice of VT treatment for a total of 387 pts enrolled


Our data suggest that ATP is a safe and effective therapeutic approach for SVTs termination, also in pts with DCM and very depressed LVEF; then, this therapeutic approach should be programmed “on” in all patients regardless LVEF.

Authors: Stefano Nardi MD, PhD (*), Luigi Argenziano MD, PhD (*)
(*) Arrhythmia, Electrophysiologic Center and Cardiac Pacing Unit, Thoracic Surgery and Cardiovascular Department, Presidio Ospedaliero Pineta Grande, Castel Volturno (CE), Italy (I)

Dual Coil leads are still on the top line but single coil ones are rapidly approaching.

With NayaMed you are a winner in both cases.

The new NayaMed single coil leads with DF-4 connector

One of the objectives of NayaMed is to offer to physicians a streamlined offer of devices and leads, bringing to market the products covering all the needs of the big majority of patients. In this respect the initial focus was on the high voltage leads with DF-1 connection and on the dual coil leads with DF-4 connector.

There is no doubt in the last 20 years dual coil leads have been preferred and until recently in most part of the world the usage of single coil leads were not more than 25% [1]. Probably the 1st reason in choosing by default the dual coil system is the results of some studies performed in the nineties, where it appears a lower DFT was demonstrated in ICD systems with 2 coils [2][3][4].

Except those early trials, there are recently more and more evidence showing that no difference was found between single coil vs. dual coil for the 1st shock arrhythmia termination for VT / VF and there is clinically equivalency in the 1st shock efficacy [5] especially if we think about the new devices on the market with 35 Joules delivered energy.

In 2003 already, Rinaldi and all. concluded there is no significant difference in DFTs between single coil and dual coil leads in the same population. The article is also enquiring about the disadvantages a dual coil lead could eventually have; promoting more fibrosis, leading to more risky and difficult extractions [6].

So we can ask why implanters worldwide are still using mostly dual coil leads despite this recent evidence. First of all, I think changing habits is not easy, than when you have good experience and no problems with an ICD lead you are used to stick to it. Then when you implant a dual coil lead you always have more options in case of a higher DFT and this is actually true as a dual coil lead gives you the option of 3 shocking vectors (RV to SVC + CAN, RV to CAN, SVC to CAN) while a single coil gives you only one option (RV to CAN). Who can do more, can do less also…

Also, there is generally no (or no more) diameter size difference between the single coil and the dual coil leads from the same family and probably most of all, when you are implanting a lead you don’t really think at its extraction.

In the last 10 years, the number of ICD implants significantly increased [7] passing in Europe from 38 implants per million in 2000 to 252 implants per million  in 2010, thus more and more people being actually saved from dying due to Sudden Cardiac Death (SCD).

This big increase in the number of implants brought an increase in the number of technical issues related to the ICD system, more precisely issues with the high voltage leads, those one being considered the “weakest link” of the ICD system [8]. Who says lead problems says lead extractions and this is the moment when potential disadvantages of a dual coil lead start to be more visible bringing the fibrosis and the increase risk extraction on the table. The centers performing lead extractions started to implant more and more single coil leads.

This year, Aoukar and all. published an article called “No benefit of a dual coil over a single coil ICD lead: Evidence from the Sudden Cardiac Death in Heart Failure Trial” and to our knowledge it is the only article where other aspects than the arrhythmia termination were analysed. The base of the article is the SCD-heft trial and in this specific analyse the authors compared different clinical aspects between the populations with single vs. dual coil ICD leads implants. The results are the following: no statistical difference in SCD risk, in the rate of inappropriate shocks, in the 1st shock efficacy, in DFT test energies and above all no statistical difference in mortality between patients implanted with a single coil versus a dual coil lead [9].

Following those evidences that are completing the ones founded since 10 years it is normal and expected that the number of implants with single coil leads to increase. In 2012, in Sweden 59.4% of all the ICD leads were single coil.

This is why, in the ease of their offer  NayaMed decided to freshly add a DF-4 Single coil lead to their portfolio; ND X4 01. It is an active fixation lead with silicone insulation and polyurethane overlay.

Earlier I was mentioning the ICD lead is probably the weakest link on the ICD system. Well with this in mind we decided to have a stronger link. Similar to its “older sister”, ND X4 02 (dual coil lead with DF-4 connector), the ND X4 01 is based on a lead model with more than 10 years of proven performance.

They are both meant to be implanted with any standard ICD with DF-4 header on the market, specifically with our dual or single chamber defibrillators, ND X4 DR and ND X4 VR.

Dr. Paolo Diotallevi

Eng. Alexandru Trif

[1] Neuzner J, Carlsson J. Dual- versus single-coil implantable defibrillator leads: review of the literature. Clin Res Cardiol. 2012;101:239-245.
[2] Gold MR, Foster AH, Shorofsky SR (1997) Lead system optimization for transvenous defibrillation. Am J Cardiol 80: 1163–1167
[3] Gold MR, Olsovsky MR, Pelini MA, Peters RW, Shorofsky SR (1998) Comparison of single- and dual-coil active pectoral defibrillation lead systems. J Am Coll Cardiol 31:1391–1394
[4] Gold MR, Olsovsky MR, DeGroot PJ, Cuello C, Shorofsky SR (2000) Optimization of transvenous coil position for active can defibrillation thresholds. J Cardiovasc Electrophysiol 11:25–29
[5] Ellis CR, Hurt JT Single-coil Versus Dual-coil ICD Lead Shock Efficacy in a Large ICD Registry. The Journal of Innovations in Cardiac Rhythm Management, 3 (2012), 953–958
[6] Rinaldi CA, Simon RDB, Geelen P, Reek P, Baszko A, Kuehl M, Gill JS (2003) A randomized prospective study of single-coil versus dual-coil defibrillation in patients with ventricular arrhythmias undergoing implantable cardioverter defibrillator therapy. Pacing Clin Electrophysiol 26:1684–1690
[7] Camm J. Letter to the editor, Implantable cardioverter defibrillator utilization Published on behalf of the European Society of Cardiology 2011
[8] Maisel WH Transvenous Implantable Cardioverter-Defibrillator Leads: The Weakest Link Circulation. 2007;115:2461-2463
[9] Aoukar  PS and all. No benefit of a dual coil over a single coil ICD lead: Evidence from the Sudden Cardiac Death in Heart Failure Trial, Heart Rhythm2013;10:970–976

Cardiac conduction disturbances : the other side of sudden cardiac death in hypertrophic cardiomyopathy.

Cardiac conduction disturbances: the other side of sudden cardiac death in hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is a myocardial disease characterized by asymmetrical hypertrophy of the heart and disarray of myocardial cells, with an unstable electrical substrate potentially causing lethal ventricular tachy-arrhythmias 1.

Cardiac magnetic resonance imaging (short axis view) of a patient affected by HCM

Cardiac magnetic resonance imaging (short axis view) of a patient affected by HCM

Sudden cardiac death is the worst feared complication of hypertrophic cardiomyopathy (HCM), and is known to be mostly related to ventricular arrhythmias such as ventricular fibrillation and ventricular tachycardia 1. However, arrhythmic sudden cardiac death can also be related to cardiac conduction disturbances (CCD), including complete atrio-ventricular block (AVB), possibly leading to prolonged asystolia. The only available treatment for such CCD, is the pacemaker (PM).

Third degree atrio-ventricular block.

Red arrows: QRS (ventricular electrical activity). Black arrows: P waves (atrial electrical activity). Atrial and ventricular activity is completely dissociated.

Red arrows: QRS (ventricular electrical activity). Black arrows: P waves (atrial electrical activity).
Atrial and ventricular activity is completely dissociated.

Second degree advanced atrio-ventricular block.

Red arrows: QRS (ventricular electrical activity). Black arrows: P waves (atrial electrical activity).  Consecutive P waves care not followed by QRS, leading to a transient asystolic pause.

Red arrows: QRS (ventricular electrical activity). Black arrows: P waves (atrial electrical activity).
Consecutive P waves care not followed by QRS, leading to a transient asystolic pause.

Although CCD are commonly seen in association with amyloidosis and glycogen storage disorders, which may themselves be associated with left ventricular hypertrophy  1, little is known about the prevalence of primitive CCD in HCM.

Primitive CCD

Case reports.

A few case reports of HCM patients with complete primitive (i.e. not secondary to surgicalor interventional procedures) AVB have been reported.

Paroxysmal complete AVB has been described in three HCM patients, with prolonged QRS duration at ECG, suffering from recurrent attacks of syncope and cardiopulmonary arrest 2. Symptoms were likely related to the AVB itself.

A case of a north Indian family including  nine HCM individuals, among whom 5 underwent PM implantation due to advanced AVB at an age of 39-55 years, has also been described 3. Two sudden cardiac deaths (25 and 51 years of age respectively) were also reported in the same family. The absence of CCD in all the HCM-affected members of the family (therefore sharing the same genetic mutation, likely associated with CCD), may be explained by the phenomenon of incomplete “penetrance” (i.e. the proportion of individuals with the mutation who exhibit clinical symptoms), which in turn is influenced by several factors, including age and gender.

Clinical studies

Prospective studies investigating the prevalence of CCD in HCM requiring permanent PM implantation are lacking. In a retrospective analysis of a small cohort of HCM patients (27 patients; 12 non obstructive) with an implanted PM, a high rate of AVB was observed4. Indications for PM included: spontaneous or induced AVB in 54% of cases (with spontaneous total AVB in over 15% of cases) and support for drug-induced bradycardia in 8% of cases 4.

A larger retrospective study of 451 HCM-patients (44% with previous syncope), also reported a high prevalence of CCD. Overall, PM was implanted in 11% of patients, either due to sinus node dysfunction or to AVB. Interestingly, in 18% of cases, at least one other family member was a PM recipient. One single mutation (E101K in the cardiac actin gene) was identified in 3 index cases (PM recipients). The authors concluded that CCD may form part of the phenotype expression of HCM and may have a familial component 5.

Iatrogenic CCD

Obstruction of the LV outflow tract in HCM, due to septal hypertrophy, is dynamic and varies with loading conditions and contractility of the left ventricle. Interventional procedures for reduction of the left ventricular outflow pressure gradient, such as septal alcohol ablation (SA) or surgical septal myectomy (SM) can be complicated by a not negligible rate of CCDs.

Septal ablation

Trans-catheter alcohol embolization of selected branches of the coronary arteries, aims at generating a circumscribed septal infarction of the left ventricle, in an attempt to reduce the left ventricular outflow tract pressure gradient due to loss of myocardial contraction. The iatrogenic septal infarction usually extends between the anterior and inferior free walls of the left ventricle, in an area commonly containing the right bundle branch (RBB) of the conduction system. Septal Ablation is therefore often complicated by RBB block occurrence 6.  AVB has also been described in up to 62% of cases of SA, but is usually transient and characterized by a spontaneous regression within 24 hours. The frequency of CCDs following SA which require permanent PM implantation has ranged between 10% and 33% across studies 6.

Subacute AVB have been also been described, occurring up to 8 days after SA 7. Predictors of subacute AVB post-ASA include: advanced age, prolonged QRS duration before or after SA, new intra-ventricular conduction disturbances or first-degree AV block after SA  7.

Septal myectomy

Septal myectomy entails surgical removal of sub-endocardial tissue in the anterior inter-ventricular septum in an attempt to reduce ventricular contractility and left ventricular outflow tract gradient. Since the left bundle branch fibers of the cardiac conduction system are adjacent to the anterior inter-ventricular septum, patients undergoing SM are at increased risk of developing left bundle branch block. Interestingly, CCDs have been shown to be significantly lower following SM as compared with SA  6,8.  The risk of complete AVB is approximately 2% with SM (higher in patients with preexisting RBB block 1 .


Current guidelines underline the importance of PM implantation when an advanced CCD occurs after SA or SM  1. However, in planning a PM implantation due to AVB in a HCM-patient, a few considerations must be taken into account, including:

  • eventual benefits expected from pacing of the right ventricular apex,  in terms of reduction of the left ventricular outflow tract gradient and consequent symptoms reduction1;
  • the individual risk of tachy-arrhythmias eventually precipitating sudden cardiac death,  with possible indication for cardioverter defibrillator implant.

Nowadays, the availability of sophisticated high-quality PM, such as those provided by NayaMed, allows safe and efficient protection from CCD and associated risk of sudden cardiac death in HCM individuals.

Dr. Annamaria Martino, Dr. Lucia De Luca and Prof. Leonardo Calò
Cardiology Department, Policlinic Casilino, ASL RMB, Rome, Italy.



  1. Gersh J. et al. 2011 ACCF/AHA Guideline for the Diagnosis and Treatment of Hypertrophic Cardiomyopathy: A Report of the American College of Cardiology Foundation/ American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol 2011; 58:e212-260
  2. Doven O et al. Abnormal His- Purkinje system conduction leading to complete atrioventricular block in patients with hypertrophic cardiomyopathy: a report of 3 cases. Jpn Heart J. 2004;45:347-52.
  3. Bahl A, Nahar Saikia U, Talwar KK. Familial conduction system disease associated with hypertrophic cardiomyopathy. International Journal of Cardiology 2008; 125: e44–e47
  4. Alves Silva LA et al. Cardiac Pacing in Hypertrophic Cardiomyopathy. A Cohort with 24 Years of Follow-Up. Arq Bras Cardiol 2008;91:250-256
  5. Barriales-Villa R et al. Severe cardiac conduction disturbances and Pacemaker implantation in patients with hypertrophic cardiomyopathy. Rev Esp Cardiol. 2010;63:985-8
  6. Agarwal S et al. Updated meta-analysis of septal alcohol ablation versus myectomy for hypertrophic cardiomyopathy. J Am Coll Cardiol 2010;55:823–34
  7. Lawrenz T et al. Predictors of complete heart block after transcoronary ablation of septal hypertrophy: results of a prospective electrophysiological investigation in 172 patients with hypertrophic obstructive cardiomyopathy. Am Coll Cardiol. 2007;49:2356-63.
  8. Talreja DR et al. Alcohol septal ablation versus surgical septal myectomy: comparison of effects on atrioventricular conduction tissue. J Am Coll Cardiol.2004;44:2329-32.

Using telemedicine to implant ICDs

Remote Technical System

Heidelberg Private Clinic’s first NayaMed Remote Tech Support experience with Dr. Med. M. Natour and personnel.

Dr. M. Natour, MD, FESC, EC is a specialist in internal medicine with a focus in Cardiology and also the director of Heidelberg Private Clinic (HPK).  This modern  medical institution utilizes its cardiac catheter laboratory and operating room to deliver medical device implantations, as well as ablation therapy, coronary angiography, balloon dilatation (PTCA) and stent implantations.  The outpatient clinic manages the complete diagnostics and therapies in the field of cardiology, such as echocardiography at rest, stress-echocardiography and transesophageal echocardiography (TEE), electrocardiograms (ECG), rest and stress-ECG and electrocardioversion.

In early April this year, during the Congress of German Society of Cardiology in Mannheim, Dr. Natour experienced the NayaMed Remote Technical Support (RTS) at our congress booth.  Excited about this new technology, he decided to use this telemedicine solution during a NayaMed ICD implant back at his private clinic in Heidelberg.

After the implant, we asked his opinion on not only our technology but also our service.  Here’s what he had to say:

NayaMed: Can you briefly describe the implant you did today: the patient indication and a general description of the procedure?

Dr. Natour: The implanted patient is 70 years old and a primary prevention patient. We implanted an ICD to prevent sudden cardiac death due to ventricular fibrillation because he is suffering from a very low ejection fraction.

We did it today and it was very good. It’s our first time doing an implant like this – with the RTS. I was very impressed as it went very easily. Thank you for your support…for being with us.

There’s nothing that I didn’t like. To be honest, it was very good! It was going as it should…it took something like 40 minutes, and to implant a dual-chamber ICD in 40 minutes is a good time. I like it!

NayaMed: For you as a user, did anything change for this implant compared to other ICD implants where a Technical Advisor was physically present in the procedure room? How confident did you feel knowing that you had a technical expert from Lausanne guiding the programmer user?

Dr. Natour: Let’s answer the second part of the question first: I did feel really confident having you in our operation room to support us because it’s the first time dealing with ICDs from NayaMed. So it’s a good feeling to know there’s an expert who may help us if there’s a need to have it. On the other hand, it was very impressing to work that way [remotely via the RTS]…and to communicate with someone from Lausanne and to know it is good for the future – it would be saving time and maybe also money to work this way because we don’t need to wait until someone comes from the company. We have support if we need it – so we can do it this way.

NayaMed: How easy was it for you and you staff to install the RTS system?

Dr. Natour: Once again, thank you for your support – for being here and helping with that – but I think it’s not a big deal to install it by ourselves. For the first time, it wasn’t clear what my staff should do, but actually if you look at the system and the device: connecting two cables in the right place is not a big deal – so I don’t think it will be a big problem in the future. Also, you are always available, so we  can always contact you.

NayaMed: How open do you think your staff is to gaining autonomy and knowledge in performing tasks initially performed by industry representatives, knowing that they can always be guided by a Technical Advisor in Lausanne?

Dr. Natour: My staff are very open-minded and supportive of us doing new technological things. But it’s always a challenge for them and the physicians’ team to work with new things. So knowing we have support in case we need it is also very good. It was a new experience also for all of us to work that way. As you saw the face of Mrs. Becker [the nurse who ran the Analyzer during the implant]: She was happy to use the RTS and she was happy to complete the tasks necessary for the implant!

NayaMed: Do you see advantages to a support solution in which a representative doesn’t have to be in the hospital?

Dr. Natour: We are in a lucky position when we don’t have to pay a lot of money when a representative is supporting us in the hospital. But I think there are clear advantages for some places and hospitals where they have to pay for the service. This will be a very good alternative to that – as long as it’s not complicated to work with it.  The service is very good, so I think it will be a step for the future.

NayaMed: Where do you see the industry heading as it relates to the growing support burden of device patients?

Dr. Natour: I think the industry and the device companies have to adapt their search to the situation with the patients because they are getting older, and they live longer – which is good but they have a lot of disease so you have to be aware of that disease and to go with the time and with the patient. To develop new devices and new possibilities to watch them and monitor them because if they get older they will not be able to visit our hospital, for example, and they will have to stay at home — so the device should be able to give me some information via telemetry. 

NayaMed: From them at home?

Dr. Natour: Yes, and, for example, not only the device data. The device should support me and provide me with information about their current situation: their weight, their blood pressure, maybe their BNP…all those things…these would really be a big help – both for patients and for doctors.

NayaMed: What is the single most important advantage you see with the RTS?

Dr. Natour: I think it’s a real advantage to work with new technology. I love to work with new technologies and to update my clinic. And this option [RTS] to work with is, for me, a kind of change – that one accepts to do the implant this way. Besides this, you save a representative from the industry. You save money. You save time waiting for them because they may be somewhere else and helping by implanting at another hospital. So we can start and do it by ourselves.

NayaMed: Would you feel confident in the future having the majority of implants through RTS?

Dr. Natour: Well, I think I was a bit not confident for the first implant. But the RTS procedure went very well, and I’m feeling good and I really feel confident. I don’t think there will be a problem to deal with that.

Alexandru Trif
NayaMed Product Manager

Lights and shadows of implantable cardioverter defibrillators implantations in hypertrophic, dilated and arrhythmogenic right ventricular cardiomyopathies.

In the past decades, implantable cardioverter defibrillators (ICDs) have definitively proved to be superior to antiarrhythmic drugs for the prevention of arrhythmic sudden cardiac death (SCD). Several studies have proved this hypothesis both for primary or secondary (i.e. after a sustained ventricular tachycardia with hemodynamic compromise or ventricular fibrillation) prevention of SCD. However, some complications often occur with ICD implantation, which may be particularly serious for young individuals.

Indications for ICD implantation in young people are mostly ion channel diseases and cardiomyopathies. The latter are structural abnormalities of the myocardium, related to genetic abnormalities, predisposing to malignant ventricular arrhythmias and requiring ICD for the prevention of SCD in some cases.

Hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is one of the most common cardiomyopathies and occurs in the 0.2% of the general population1. It is characterized by localized asymmetrical hypertrophy of the heart and disarray of myocardial cells and filaments. This leads to impaired transmission of electrophysiologic impulses, with an unstable electrical substrate, potentially causing lethal ventricular tachyarrhythmias and SCD.

Hypertrophic cardiomyopathy

Short axis view of a cardiac magnetic resonance imaging of a patient affected by hypertrophic cardiomyopathy involving the interventricular septum and the anterior wall of the left ventricle.

ICD implantation in HCM: lights

A minority of patients with HCM are judged to be at increased risk for SCD, whose rate is estimated to be about 1% per year 2. However, malignant ventricular arrhythmias remains the most frequent cause of death in this population.

Beta-blockers have failed to demonstrate significant protection from SCD in HCM patients. Type I and III anti-arrhythmic drugs, including amiodarone, have been abandoned because of inefficacy and pro-arrhythmic side effects. Experiences with endocardial and epicardial mapping and ablation in HCM are poor and limited to highly selected patients.

ICDs, conversely, have been proved effective in terminating life-threatening ventricular tachyarrhythmias in HCM and are currently considered the only available tools altering the natural course of the disease and prolonging life.

Appropriate intervention rates of ICD in HCM have been esteemed to be about 11% and 4% for secondary and primary prevention respectively3.

Current recommendation for ICD in HCM

HCM has heterogeneous clinical manifestations in different individuals and a not well predictable clinical course. Targeting HCM-patients for prophylactic ICD implantation can therefore be challenging. However, some “risk factors” have been individuated, that commonly guide the decision for ICD implantation. Current international guidelines recommend ICD in all cases of secondary prevention or when familiar history of SCD, marked left ventricular (LV) hypertrophy or recent unexplained syncopal episodes are present. The role of ICD is uncertain for non-sustained VT or an abnormal blood pressure response with exercise.

ICD implantation in HCM: shadows

Previous studies have reported up to 5.1%/year rate of ICD-related complications in HCM4.

The most frequently reported is inappropriate shock delivery, mostly due to erroneous detection and treatment of atrial fibrillation by the ICD. A retrospective study on 334 consecutive HCM patients with an ICD, showed a rate of appropriate vs. inappropriate shock delivery of 2.3 and 4.6%/year5. Moreover, a recent meta-analysis involving 2190 ICD-recipients affected by HCM, showed a rate of appropriate vs. inappropriate ICD interventions of 3.3 vs. 4.8%/year respectively4.

Another extremely rare complication with ICDs in HCM, is represented by loss of capture due to high pacing thresholds (i.e. energy required for effective right ventricular pacing). This is related to ventricular hypertrophy and may be prevented by accurate individuation of the optimal pacing threshold during ICD programming.

Lengthened mitral valve leaflets, and left ventricular outflow tract obstruction due to LV hypertrophy, also confers a relatively higher risk of infection and endocarditis to HCM patients, which must be considered when an ICD implantation is programmed. Moreover, since ICD implantation in HCM is commonly performed at a relatively young age, patients are supposed to necessitate of a number of interventions for pulse generator substitution over their entire life. For this reason, risk of infection and endocarditis (related to ICD substitutions) is amplified. Eventual needing of ICD and intra-cardiac leads extraction over time must be considered. This is a high-risk procedure, possibly complicated by cardiac tamponade, shock, anemia, arrhythmias or even death.

Finally, ICD implantation can be accompanied by depression, anxiety, reduced quality of life, particularly in young people.

Idiopathic dilated cardiomyopathy

Idiopathic dilated cardiomyopathy (IDCM) is a myocardial disease characterized by LV dilation and systolic dysfunction, commonly resulting in heart failure (HF) and for whom an etiological basis cannot be identified. IDCM is relatively rare (36.5% new cases/year/100.000 persons) but accounts for nearly 10.000 deaths/year in the United States, both due to HF and arrhythmic SCD6.

Idiopathic dilated cardiomyopathy.

Long axis view of a cardiac magnetic resonance imaging of a patient affected by dilated  cardiomyopathy

ICD implantation in IDCM: lights

ICD are effective for the prevention of SCD in IDCM and can favorably alter the natural course of the disease. Previous studies have showed a rate of appropriate interventions of 5 to 7.5%/year in IDCM-patients with an ICD implanted for primary prevention 7-8. A large meta-analysis has showed a reduction of mortality with ICD of about 3.5%/year compared to the best medical therapy in IDCM 9.

Recommendation for ICD in IDCM

The most important risk factor for ventricular arrhythmias in primary prevention of SCD in IDCM, is represented by severe contractile dysfunction, quantified by the measurement of the ejection fraction (EF) at echocardiography. Functional status, assessed by the New York Heart Association (NYHA) class, also plays a role.

Current international guidelines recommend ICD always for secondary prevention. In case of primary prevention, ICD must be implanted in patients with LVEF ≤35%  and NYHA class II and III10. However, in a real-life setting, the decision making for patients with IDCM is more complex, because issues such as additional cardiac resynchronization therapy (CRT), co-morbidities, the potential to improve LVEF over time, and eventual genetic etiology also should be considered. With regard to the last issue, carriers of mutations in gene encoding for laminin, are tough to be at increased risk of complete atrio-ventricular block, malignant ventricular arrhythmias and SCD, and may therefore require ICD implantation independently from the EF%.

ICD implantation in IDCM: shadows and warnings

Some shadows obscure the scenario of SCD prevention with ICDs in IDCM.

An important issue regards the high number of patients to be treated in order to save one life because of a currently adopted risk stratification process that appears to lack specificity.

Another topic is the correct timing for ICD implantation for primary prevention. A post hoc analysis of the DEFINITE trials 11 showed that only patients who had received their ICD not later than 3 months after the diagnosis of IDCM would have benefit from implant. However, a significant number of IDCM-individuals show marked improvement of the EF over time, up to values higher than those for which ICD implantation is currently recommended. The goal therefore, appears to be an early and correct individuation of those subjects who will have a negative clinical course, and will therefore require an early ICD implantation for primary prevention.

Similarly to HCM, ICD-related complications have been also reported by various studies, among whom:

  1. inappropriate shocks, with consequent reduction of quality of life;
  2. infections;
  3. risks related to eventual lead extractions;
  4. depression and anxiety.

Arrhythmogenic right ventricular cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetic cardiomyopathy characterized by progressive fibro-fatty replacement of the right ventricular myocardium, sometimes extending also to the left ventricle. The clinical presentation is usually related to ventricular tachycardia (VT) with a left bundle branch block pattern or ventricular fibrillation (VF) leading to SCD. ARVC is a progressive disease ultimately leading to HF.


  Panel A


Panel B

Short (Panel A) and long  axis views (panel B) of a cardiac magnetic resonance imaging of a patient affected by arrhythmogenic right ventricular cardiomyopathy, with evident fibro-fatty replacement of the right ventricle wall, the apex and partial involvement of the left ventricle wall.

ICD implantation in ARVC: lights

The therapeutic options for ventricular arrhythmias in ARVC include catheter ablation and antiarrhythmic drugs such as beta blockers, sotalol and amiodarone. However, these strategies have proved to improve symptoms but not to increase survival. Nowadays, ICD remains the most effective safe-guard against SCD in ARVC.

In a large multicenter international study enrolling ARVC patients with an ICD implanted for primary prevention, appropriate device interventions were observed in one fourth of patients after 5 years. The annual rate of potentially “life-saving” shocks against VF was 3.3% and the estimated benefit of ICD implantation was of 23% after 2 years 12. Another recent prospective study enrolling a cohort of ARVC patients with an ICD implanted for primary prevention, reported appropriate device interventions in nearly one-half of individuals over a period of 4.7 years 13.

Recommendation for ICD in ARVC

As for IDCM and HCM, ICD implantation is recommended in ARVC for secondary prevention (aborted SCD, VF or hemodynamically unstable sustained VT). ICD is also recommended for primary prevention in patients with LVEF≤35%, severe right ventricular dilation and/or dysfunction, a syncopal episode suggestive for VT or VF or an affected family member with SCD. Other risk factors include: non-sustained VT, early onset of the disease and competitive sport activity.

ICD implantation in ARVC: shadows.

Several studies have proved a relatively high incidence of device-related complications in ARVC patients with an implanted ICD. In a study of 132 patients, five individuals required an additional lead because of pacing failure and one patient died from endocarditis secondary to device infection 14. Progression of fibro-fatty replacement of the myocardial tissue has been associated with high pacing thresholds and impedances and eventual loss of capture. Up to 37% lead-related complication in 7 years have been described in ARVC patients with an implanted ICD 15.


The decision regarding ICD implantation is highly significant for any individual at risk of SCD. The clinical decision-making process itself is complex and imply consideration of a number of different aspects. Despite ICD is the only life-prolonging therapy in cardiomyopathies, eventually associated complications should be considered.

Modern technology, such as that utilized by NayaMed, has currently developed sophisticated algorithms allowing an accurate discrimination of supraventricular from ventricular arrhythmic episodes and properly guiding ICD therapies. A growing knowledge of those algorithms by the cardiologists would hopefully reduce the rate of inappropriately delivered shocks by ICDs.

Reliable RV lead alerts and RV lead integrity algorithms, also a constant automatic measurement of leads’ impedances and P, R Waves amplitude have also been implemented in the ICDs of NayaMed, preventing the problems caused by a lead failure. However, despite such algorithms, a complete abolition of ICD-related complications in cardiomyopathies is unreliable. Therefore, an accurate risk stratification appears necessary, as well as a careful weigh of the relative risks and benefits of ICD implantation in each individual.

Dr. Annamaria Martino
Dr. Leonardo Calo
Policlinico Casilino
Roma, Italy


1)      Gersh J, Maron BJ, Bonow RO et al. 2011 ACCF/AHA Guideline for the Diagnosis and Treatment of Hypertrophic Cardiomyopathy: A Report of the American College of Cardiology Foundation/ American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol 2011; 58:e212-260

2)      Maron BJ. Hypertrophic cardiomyopathy: a systematic review. JAMA 2002; 287:1308-1320

3)      Maron BJ, Spirito B, Shen WK et al. Implantable cardioverter defibrillators  and prevention of sudden cardiac death in hypertrophyc cardiomyopathy. JAMA 2007; 298: 405-412

4)      O’Mahony C, Lambiase PD, Quarta G et al. The long-term survival and the risk and benefits of implantable cardioverter defibrillators in patients with hypertrophic cardiomyopathy. Heart 2012;98:116-125

5)      Schinkel AF, Vriesendorp PA, Sijbrands EJ et al. Outcome and complications after implantable cardioverter defibrillator therapy in hypertrophic cardiomyopathy: systematic review and meta-analysis. Circ Heart Fail 2012;5:552-559

6)      Codd MB, Sugrue DD, Gersh BJ et al.  Epidemiology of idiopathic dilated and hypertrophic cardiomyopathy. A population based study in Olmsted County, Minnesota, 1975–1984. Circulation 1989;80:564–72

7)      Bardy GH, Lee KL, Mark DB, Poole JE et al. Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT) Investigators. Amiodarone or an implantable cardioverter-defibrillator for congestive heart failure. N Engl J Med 2005;352:225–237.

8)      Kadish A, Dyer A, Daubert JP et al; Defibrillators in non-ischemic Cardiomyopathy Treatment Evaluation (DEFINITE) Investigators. Prophylactic defibrillator implantation in patients with nonischemic dilated cardiomyopathy. N Engl J Med 2004;350:2151–2158.

9)      Desai AS, Fang JC, Maisel WH, Baughman KL. Implantable defibrillators for the prevention of mortality in patients with nonischemic cardiomyopathy: a meta-analysis of randomized controlled trial. JAMA 2004;292: 2874–287

10)  Zipes DP; Camm AJ, Borggrefe M et al. ACC/AHA/ESC 2006. Guidelines for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death. Europace 2006; 8:746-837

11)  Kadish A, Schaechter A, Subacius H et al. Patients with recently  diagnosed nonischemic cardiomyopathy benefit from implantable cardioverter defibrillators. J Am Coll Cardiol 2006;47:2477–2482

12)  Corrado D et al. Prophylactic Implantable Defibrillator in Patients With Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia and No Prior Ventricular Fibrillation or Sustained Ventricular Tachycardia. Circulation. 2010;122:1144-1152.

13)  Bhonsale A, James CA, Tichnell C  et al. Incidence and predictors of implantable cardioverter-defibrillator therapy in patients with arrhythmogenic right ventricular dysplasia/ cardiomyopathy undergoing implantable cardioverter-defibrillator implantation for primary prevention. J Am Coll Cardiol, 2011;58:1485-96

14)  Corrado D, Leoni L, Link MS et al. Implantable cardioverter-defibrillator therapy for prevention of sudden death in patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia. Circulation 2003;108:3084–91.

15)  Wichter T, Paul M,Wollmann C et al. Implantable cardioverter/defibrillator therapy in arrhythmogenic right ventricular cardiomyopathy. Single-center experience of long-term follow-up and complications in 60 patients. Circulation 2004;109:1503–8.

How NayaMed is revolutionizing the medical device industry


See how NayaMed is revolutionizing the medical device industry :

Click on the link below to read the “A Day With NayaMed” interactive eBook, and to meet many of the characters in this eBook

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This video was produced by Nayamed International Sàrl
Concept: Frederic Briguet Design: Edouard Ratiarson, MemeBoutique
Reviewers: Mary Soranno, Arnaud Martin.

“The content of this video is informative only. It does not contain nor replace any medical diagnosis. For medical diagnosis, you should always contact your healthcare professional. Always talk with your doctor about diagnosis and treatment information. Bear in mind that all products/therapies/procedures carry risks. This product/therapy/procedure is not right for everyone. Contact your doctor to see if it is right for you. A prescription is required.”

NayaMed Cool.Cast – Topic 1 – AT Management


At NayaMed, we realize that you have an endless number of choices of what to read on the internet, especially as they relate to medical devices. Therefore, I’d like to say thank you for landing here, on the NayaMed blog to learn more about the AT Management Cool.Cast series.

So, why did we launch the new Cool.Cast Series with AT Management? It’s simple; the incidence of Atrial Fibrillation (AF) is growing at an alarming rate. Our Technical Advisors can personally attest to, and have seen first-hand, that devices can be utilized by clinicians to detect subclinical and symptomatic AF, thus helping to address this growing problem. Before continuing, I believe it’s important to explain that our AT Management Cool.Cast Series will not teach you how to manage your AT device patients, you know this far better than we do. What our AT Management Cool.Cast Series will do, is to strangely entertain and uniquely train on the AT Management features in NayaMed devices.

The first delivery of the AT Management Cool.Cast Series is an infographic, ‘A look at the evolution of medical devices & equipment in the past century’. You may have already seen it and if so, we hope you enjoyed the ‘experience’. We encourage you to pin it, post it, print it, tweet it, blast it, read it again and again….there are no rules so why not have some fun.

The second delivery of the AT Management Cool.Cast Series is a Tech Tip called ‘Better Diagnosis of Atrial Flutter & Atrial Fibrillation in NayaMed Pacemakers’. I think you’ll find that our Tech Tips are a fast and simple way to learn about NayaMed devices. In fact, after reading our AT Management Tech Tip, we believe you’ll say to yourself, sure, this is something that I can keep in the back of my mind for my AT patients.

The final delivery of the AT Management Cool.Cast Series is a NayaCast titled ‘Blanked Flutter Search’. With this video simulation, we explain an AT feature that is, in our opinion, not wholly appreciated and maybe even sometimes misunderstood. We’re confident, though, that after experiencing the ‘Blanked flutter Search’ NayaCast you’ll see that the feature is actually quite smart and an important one to have in a device for your AT/AF patients.

Now that you know what to expect from our AT Management Cool.Cast Series, I don’t think I’d be doing a thorough job if I didn’t describe all of our AT Management features – AT is the topic after all.

So, without further ado, here are the AT Management features that can benefit patients with AT/AF:

  1. Mode switch which, when coupled with Blanked Flutter Search, allow patients with regular Atrial Flutter, or AF, to appropriately mode switch. Seems like a normal thing to have but not everyone has this!
  2. Conducted AF Response (CAFR) which regularizes the ventricular rhythm during an AT/AF episode and thus aims to minimize the symptoms of an irregular rhythm due to AT/AF. Again, a nice feature to have in your back pocket for those patients that are symptomatic from an irregular rhythm due to AT/AF.
  3. High Rate Episodes Collected Data to help identify true AT/AF as early as possible. Our Tech Tip talks about how to use and interpret the results in your AT patients.
  4. Atrial Arrhythmia Trend to help determine the time spent each day in an AT/AF and over time.
  5. VRate During AT/AF Histogram to help determine whether the ventricular rate is controlled while in AT/AF.
  6. Non-competitive atrial pacing (NCAP) to prevent pacing during the atrial vulnerable period, which could induce an AT/AF episode. Not a game changer but again, good to have.

So, with this blog post, we kick off our Cool.Cast Series with AT Management.

Mary Soranno

NayaMed Technical Advisor


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