Author + information
- A.M. Sinha,
- E. Martens and
- W. Hohenforst-Schmidt
Patients (pts) with cardiomyopathy (CM) and impaired ejection fraction (EF) have increased risk of ventricular tachycardia or fibrillation (VT/VF). The wearable cardioverter defibrillator (WCD) protects pts with VT/VF until their response to guideline directed medical therapy (GDMT) can be ascertained. Adherence to GDMT results in better pt outcomes, including improved EF and reduced risk of sudden cardiac death (SCD).
Understand the impact of GDMT combined with WCD use on the decision to implant an cardioverter defibrillator (ICD) after early diagnosis of heart failure.
A single centre registry of 118 WCD pts was conducted. All pts had EF recorded at baseline, and 92 pts had EF recorded at day 90. Pts were excluded if they had been previously implanted with an ICD (3) or had EF >35% at baseline (4). Thus, analysis was performed on 85 pts.
Pts were grouped by EF ≤35% (impaired) or >35% (improved) at follow up. The Table shows the percentage of pts receiving an ICD. Comparison of WCD use in the impaired and improved groups indicated that median days of wear (49 vs 45 d) and hours of daily use (22.9 vs 22.6 h) were independent of EF at follow up,(p>0.05). The distribution of gender (84% vs 70% male), median age (71 vs 64 y) and starting EF (26% vs 25%) was similar between groups (p>0.05). The percent pts with improvement in EF was similar in ischemic vs non-ischemic CM (p>0.05). Symptom based prescription of heart failure medication was similar when compared by EF at follow up. In the absence of VT/VF, the decision to implant an ICD correlated with EF at follow up (84% in EF impaired vs 7% EF in improved pts, p<0.001). There were 3 pts with non-ischemic CM that were shocked for sustained VT/VF. All episodes were converted by the first shock, and survival was documented at least 24 hours post shock. There were no deaths, and no pt was shocked inappropriately. There were 3 episodes of new atrial fibrillation detected as well.
|Total||EF ≤35%||EF >35%||p-value|
|ICD, N (%)||48 (57)||46 (84)||2 (7)||<0.001|
|No ICD, N (%)||32 (38)||4 (7)||28 (93)||----|
|Unknown, N (%)||5 (6)||5 (9)||0 (0)||----|
Overall, during WCD use, 35% of pts, both ischemic and non-ischemic CM, manifest improved EF by 90 days. The decision to implant an ICD was influenced by EF improvement and occurrence of spontaneous VT/VF. The WCD protects pts from SCD until a patient’s response to GDMT can be determined.