Non-ischemic cardiomyopathy and ICD pacemakers have been evaluated in randomized controlled clinical trials.
The 2002 Cardiomyopathy Trial (CAT) authors stated:
The trial was terminated after the inclusion of 104 patients because the all-cause mortality rate at 1 year did not reach the expected 30% in the control group. In August 2000, the vital status of all patients was updated by contacting patients, relatives, or local registration offices. One hundred four patients were enrolled in the trial: Fifty were assigned to ICD therapy and 54 to the control group. Mean follow-up was 22.8}4.3 months, on the basis of investigatorsf follow-up. After 1 year, 6 patients were dead (4 in the ICD group and 2 in the control group). No sudden death occurred during the first and second years of follow-up. In August 2000, after a mean follow-up of 5.5±2.2 years, 30 deaths had occurred (13 in the ICD group and 17 in the control group). Cumulative survival was not significantly different between the two groups (93% and 80% in the control group versus 92% and 86% in the ICD group after 2 and 4 years, respectively).
The 2002 CAT trial authors concluded:
ICD therapy did not reveal any survival benefit in the setting of DCM [dilated cardiomyopathy] of recent onset and impaired LV function (EF ≤ 30%). This was most likely due to the low overall mortality rate in the control group. However, even in patients with a significantly increased mortality rate caused by a lower EF [ejection fraction] and nonsustained VTs [ventricular tachycardias], ICD therapy did not reveal any survival benefit. Therefore, the results of CAT do not favor prophylactic ICD implantation in patients with DCM of recent onset and impaired LVEF without any further risk stratification.
The 2003 AMIOVERT trial, the authors stated:
The Trial randomized 219 patients into an ICD pacemaker group and Amiodarone group. The study was stopped when the prospective stopping rule for futility was reached. The percent of patients surviving at one year (90% vs. 96%) and three years (88% vs. 87%) in the amiodarone and ICD groups, respectively, were not statistically different (p = 0.8). Quality of life was also similar with each therapy (p = NS).
The 2003 AMIOVERT trial authors concluded:
Not only was total mortality found not to be statistically different with amiodarone and ICD in patients with NIDCM [nonischemic dilated cardiomyopathy] and NSVT [nonsustained ventricular tachycardia], but there was also a trend towards amiodarone being more effective than the ICD in preventing symptomatic VT [ventricular tachycaradia]. The lack of statistically different survival rates and the trend towards a substantial cost savings with amiodarone provide an argument favoring amiodarone as the initial therapy to prevent death among patients with NIDCM [nonischemic dilated cardiomyopathy] and NSVT [nonsustained ventricular tachycardia].
The 2004 DEFINITE trial4, the authors stated:
We enrolled 458 patients with nonischemic dilated cardiomyopathy, a left ventricular
ejection fraction of less than 36 percent, and premature ventricular complexes or nonsustained ventricular tachycardia. A total of 229 patients were randomly assigned to receive standard medical therapy, and 229 to receive standard medical therapy plus a single-chamber ICD.
Patients were followed for a mean (}SD) of 29.0}14.4 months. The mean left ventricular
ejection fraction was 21 percent. The vast majority of patients were treated with angiotensin-converting.enzyme (ACE) inhibitors (86 percent) and beta-blockers (85 percent). There were 68 deaths: 28 in the ICD group, as compared with 40 in the standard-therapy group (hazard ratio, 0.65; 95 percent confidence interval, 0.40 to 1.06; P=0.08).
The 2004 DEFINITE trial authors concluded:
On the basis of our results, the routine implantation of a cardioverter.defibrillator cannot be recommended for all patients with nonischemic cardiomyopathy and severe left ventricular dysfunction.
The 2016 DANISH trial5, the authors stated:
In a randomized, controlled trial, 556 patients with symptomatic systolic heart
failure (left ventricular ejection fraction, ≤35%) not caused by coronary artery disease
were assigned to receive an ICD, and 560 patients were assigned to receive usual
clinical care (control group). In both groups, 58% of the patients received CRT. The
primary outcome of the trial was death from any cause. The secondary outcomes
were sudden cardiac death and cardiovascular death.
After a median follow-up period of 67.6 months, the primary outcome had occurred
in 120 patients (21.6%) in the ICD group and in 131 patients (23.4%) in the control group (hazard ratio, 0.87; 95% confidence interval [CI], 0.68 to 1.12; P = 0.28). Sudden cardiac death occurred in 24 patients (4.3%) in the ICD group and in 46 patients (8.2%) in the control group (hazard ratio, 0.50; 95% CI, 0.31 to 0.82; P = 0.005). Device infection occurred in 27 patients (4.9%) in the ICD group and in 20 patients (3.6%) in the control group (P = 0.29).
The 2016 DANISH trial authors concluded:
In conclusion, in our trial, prophylactic ICD implantation in patients with symptomatic systolic heart failure that was not caused by coronary artery disease was not found to reduce long-term mortality.
Based upon four (4) randomized controlled clinical trials, the routine use of ICD pacemaker implantation for non-ischemic cardiomyopathy for the primary prevention of sudden cardiac death is not associated with any survival benefit compared with optimal medical therapy. This conclusion indicates that criteria #7 or criteria #9 in the National Coverage Determination (NCD) for Implantable Automatic Defibrillators (20.4) (Publication Number 100-3; Version Number 3; Manual Section Number 20.4; Effective Date: January 27, 2005; Implementation Date: January 27, 2005) may no longer valid.
Thank you very much for your consideration.