Icds and prevention of sudden cardiac death

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Implantable Cardioverter-Defibrillators and Prevention Of Sudden Cardiac Death In
Hypertrophic Cardiomyopathy: Commentary from F1000
Melvin Cheitlin
F1000 Medicine. 2008; 2008 Medicine Reports Ltd.
Posted 05/16/2008 Maron BJ, Spirito P, Shen WK, Haas TS, Formisano F, Link MS, Epstein AE, Almquist AK, Daubert JP, Lawrenz T, Boriani G, Estes NA, Favale S, Piccininno M, Winters SL, Santini M, Betocchi S, Arribas F, Sherrid MV, Buja G, Semsarian C, Bruzzi PJAMA 2007 Jul 25 298(4):405-12 Commentary from Faculty Member Melvin Cheitlin
Changes Clinical Practice: Hypertrophic cardiomyopathy (HCM) patients at high risk of sudden death with a history of aborted sudden death or one or more
of the risk factors described below should be considered for implanted cardioverter-debrillator (ICD) implantation.
The most feared complication in patients with hypertrophic cardiomyopathy (HCM) is sudden death. Patients considered to be at high risk are those
who have had an episode of ventricular fibrillation or ventricular tachycardia and those with one or more of four other risk factors. This study is
definitive in proving that sudden death can be prevented in these high-risk patients by implantation of a cardioverter-defibrillator. This was true in
both secondary and primary prevention, occurred in 27% of patients taking amiodarone and was four times more common in those with alcohol ablation than in
those with surgical septal myectomy. Since the mean age of patients was 42 years and almost half the patients were NYHA class I or II, this intervention was cost
effective and prevented premature death in a large number of relatively young patients. The authors have been studying patients with HCM for many years and
report a multicentric registry study of implanted cardioverter-debrillators (ICDs) in 506 HCM patients considered to be at high risk and followed for over three and
a half years. High risk was defined as having had a documented episode of resuscitation from ventricular tachycardia (VT) or fibrillation (secondary prevention) or
one or more of four other risk factors: (1) History of HCM-related sudden death in a first degree relative or more distant relative under 50 years of age; (2) Severe
LVH -- maximum wall thickness 30mm; (3) Non-sustained VT with a rate of more than 120/min on 24-hour monitoring; (4) Unexplained syncope inconsistent with
a neurocardiogenic origin. One quarter of the patients had an appropriate discharge within five years of implantation and the likelihood of appropriate discharge
was the same in patients with only one risk factor as it was in those with two or more. They showed that sudden death could be prevented in these high-risk
patients and that patients on amiodarone had the same number of appropriate discharges as others. Most worrisome is the finding that appropriate discharges
occurred in 10.3%/year in patients who had had alcohol septal ablation and in only 2.6%/year in those with surgical septal myectomy. The authors are not
necessarily recommending ICD implantation in everyone with one risk factor and give examples of older patients who are at less risk of sudden death where ICD
implantation would not be appropriate. Although this is an observational study and there is no comparison group of patients with HCM not at high risk without ICD
implantation, this study is powerful evidence that in the high-risk group of HCM patients, sudden death can be eliminated. The patients who died during the
follow-up period died of heart failure with systolic dysfunction or from embolic stoke. If these can be avoided, it is likely that the patients may live a normal lifespan.
Further exploration of the possibility that alcohol septal ablation may predispose to a higher risk of sudden death than surgical septal myectomy is needed.
Faculty of 1000 Medicine Evaluations, Dissents and Author responses for: [Maron BJ et al. Implantable cardioverter-defibrillators and prevention of sudden cardiac death in hypertrophic cardiomyopathy. JAMA 2007 Jul 25 298 (4) :405-12]. 2008 Mar 28. The following article was selected and commented on by this Faculty Member of Faculty of 1000 Medicine:
Melvin Cheitlin, University of California at San Francisco, School of Medicine, United States of America
Competing interests: No potential interests relevant to this article were reported.

Source: http://www.hcmforum.de/hocm_hncm_hcm/ICDs_and_Prevention_of_Sudden_Cardiac_Death.pdf