Clinical outcome of cardiac resynchronization therapy in dilated-phase hypertrophic cardiomyopathy
1Cardiac Arrhythmia Center, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
Insights
Patients with dilated-phase hypertrophic cardiomyopathy (DHCM) experience worse outcomes after cardiac resynchronization therapy (CRT) compared to those with idiopathic dilated cardiomyopathy (IDCM). DHCM outcomes were similar to or worse than ischemic cardiomyopathy (ICM) patients.
Area of Science:
- Cardiology
- Heart Failure Management
- Cardiac Electrophysiology
Background:
- Cardiac resynchronization therapy (CRT) is established for non-ischemic cardiomyopathy.
- Dilated-phase hypertrophic cardiomyopathy (DHCM) patients were excluded from prior CRT trials.
- Understanding CRT outcomes in DHCM is crucial for patient selection.
Purpose of the Study:
- To compare the clinical outcomes of CRT in DHCM versus idiopathic dilated cardiomyopathy (IDCM) and ischemic cardiomyopathy (ICM).
- To evaluate the effectiveness of CRT in a population with DHCM.
Main Methods:
- Retrospective study of 312 patients undergoing CRT.
- Patient groups included DHCM (n=16), IDCM (n=231), and ICM (n=65).
- CRT response defined as ≥15% reduction in left ventricular end-systolic volume at 6 months.
Main Results:
- DHCM patients had significantly higher total mortality, cardiac mortality, and heart failure hospitalizations compared to IDCM patients.
- Outcomes for DHCM patients were similar to or worse than ICM patients, though not statistically significant.
- CRT response rates were numerically lower in DHCM but did not reach statistical significance.
Conclusions:
- DHCM is associated with worse clinical outcomes following CRT compared to IDCM.
- DHCM patients demonstrate a distinct response to CRT, warranting further investigation.
- Current CRT guidelines may need re-evaluation for DHCM patient subgroups.
Backgrounds:
Clinical trials have demonstrated that cardiac resynchronization therapy (CRT) is effective in patients with "non-ischemic cardiomyopathy". However, patients with dilated-phase hypertrophic cardiomyopathy (DHCM) have been generally excluded from such trials. We aimed to compare the clinical outcome of CRT in patients with DHCM, idiopathic dilated cardiomyopathy (IDCM), or ischemic cardiomyopathy (ICM).
Methods:
A total of 312 consecutive patients (DHCM: n = 16; IDCM: n = 231; ICM: n = 65) undergoing CRT in Fuwai hospital were studied respectively. Response to CRT was defined as reduction in left ventricular end-systolic volume (LVESV) ≥ 15% at 6-month follow-up.
Results:
Compared with DHCM, IDCM was associated with a lower total mortality (HR: 0.35, 95% CI: 0.13-0.90), cardiac mortality (HR: 0.29; 95% CI: 0.11-0.77), and total mortality or heart failure (HF) hospitalizations (HR: 0.34, 95% CI: 0.17-0.69), independent of known confounders. Compared with DHCM, the total mortality, cardiac mortality and total mortality or HF hospitalizations favored ICM but were not statistically significant (HR: 0.59, 95% CI: 0.22-1.61; HR: 0.59, 95% CI: 0.21-1.63; HR: 0.54, 95% CI: 0.26-1.15; respectively). Response rate to CRT was lower in the DHCM group than the other two groups although the differences didn't reach statistical significance.
Conclusions:
Compared with IDCM, DHCM was associated with a worse outcome after CRT. The clinical outcome of DHCM patients receiving CRT was similar to or even worse than that of ICM patients. These indicate that DHCM behaves very differently after CRT.
Related Concept Videos
01:30Cardiomyopathy II: Dilated Cardiomyopathy
01:29Cardiomyopathy V: Interprofessional Care
01:29Cardiomyopathy III: Hypertrophic Cardiomyopathy
01:29Heart Failure II: Pathophysiology
01:29Cardiomyopathy IV: Restrictive Cardiomyopathy
01:30Heart Failure IV: Classification and Diagnostic Evaluation