| Authors |
| Moss AJ, Hall WJ, Cannom DS, et al. |
| Title |
| Cardiac-Resynchronization Therapy for the Prevention of Heart-Failure Events |
| References |
| N Engl J Med 2009;361:1329-38. |
| Background |
| At the time of initiation of this study, CRT has been shown to reduce mortality and hospitalization in patients with severe symptoms (NYHA III and IV), reduced LVEF and prolonged QRS duration. CRT has also been seen to reverse left ventricular modeling and improve cardiac function in patients with less advanced heart failure but the impact of hard clinical outcomes has not been assessed. |
| Purpose |
| To examine whether CRT, when added to an implantable cardioverter-defibrillator (ICD), positively affects clinical outcomes in patients with asymptomatic or mild heart failure (NYHA class I or II) and a wide QRS complex. |
| Design |
- Multicentre, randomized trial (3:2 ratio to receive CRT with an ICD or ICD only)
- 1820 patients, ≥21 years with ischemic cardiomyopathy (NYHA class I or II) or nonischemic cardiomyopathy (NYHA class II only), LVEF ≤30%, and QRS ≥130 msec
|
| Exclusion Criteria |
- clinical indication for CRT; existing implanted pacemaker, ICD, or resynchronization device; NYHA class III or IV; previous CABG, PCI or enzyme positive MI in the past 3 months; atrial fibrillation in the previous month
|
| Follow-Up |
| Average of 2.4 years (stopped prematurely, according to prespecified efficacy boundary) |
| Treatment Regimen |
- CRT with an ICD (CRT-ICD group) vs. ICD only (ICD group).
- clinical follow-up at month 1 and every 3 mos. until end of trial; 2D echo at baseline and at 1 year to assess for LVEDV, LVESV, LVEF;
- adjudication of endpoint events by independent mortality and heart failure committee; diagnosis of heart failure = signs/symptoms of heart failure responding to iv outpatient therapy or oral/parenteral in-hospital therapy
|
| Results |
Primary Endpoints CRT-ICD
n = 1089 | ICD
n =731 | Hazard Ratio | p |
|---|
| Composite of death from any cause or nonfatal HF (1st event) |
|---|
| 17.2% | 25.3% | 0.66 (0.52-0.84) | 0.001 | | Heart failure event |
|---|
| 13.9% | 22.8% | 0.59 (0.47-0.74) | <0.001 | | Death at anytime* |
|---|
| 6.8% | 7.3% | 1.00 (0.69-1.44) | 0.99 | *all deaths during study, including those that occurred after first heart failure event- Among patients with ischemic or nonischemic cardiomyopathy, the hazard ratio for the primary endpoint were similar and significantly lower with CRT-ICD (HR 0.64 [0.52-0.88], p=0.003 vs. HR 0.62 [0.44-0.89], p=0.01)
- Although statistically non-significant for death, CRT-ICD also significantly reduced HF events in ischemic or nonischemic cardiomyopathy patients (HR 0.58 [0.44-0.78], P<0.001 vs. HR 0.59 [0.41-0.87], p=0.01)
- From prespecified subgroup, CRT-ICD therapy greater benefit for QRS ≥150 msec [HR 0.48, (0.37-0.64)] vs. QRS <150 msec [HR 1.06, (0.74-1.52)], p=0.001
- LVEDV change (1yr) : 52 (CRT-ICD) vs. 15 mL (ICD) decrease from baseline; p <0.001
- LVDSV change (1yr): 57 (CRT-ICD) vs. 18 mL (ICD) decrease from baseline; p <0.001
- LVEF change (1yr): 0.11 (CRT-ICD) vs. 0.03 (ICD) increase from baseline; p <0.001
|
| Summary |
| When added to an ICD, CRT reduces the combination of death or nonfatal heart failure in patients with a low LVEF, NYHA class I or II symptoms and a wide QRS interval. This CRT-ICD benefit is primarily driven by a significant reduction in HF events, as survival rates were similar in both groups and not significantly different. |