Faculty Bibliography

BACKGROUND:End-stage (ES) hypertrophic cardiomyopathy (HCM) has been considered a particularly grim and unfavorable disease complication, associated with substantial morbidity and mortality, frequently requiring heart transplant. Previous reports have included small numbers of patients with relatively short follow-up, predominantly in prior treatment eras. OBJECTIVES:The purpose of this study was to re-evaluate clinical profile and prognosis for end-stage heart failure in a large HCM cohort with contemporary management strategies. METHODS:Patients at Tufts HCM Institute, from 2004 to 2017, were identified with ES and systolic dysfunction (ejection fraction [EF] <50%), followed for 5.8 ± 4.7 years (up to 18 years). RESULTS:Of the 2,447 patients, 118 (4.8%) had ES-HCM (EF 39 ± 9%; range 12% to 49%) at age 48 ± 15 years. Notably, over follow-up, 57 patients (48%) achieved clinical stability in New York Heart Association functional classes I/II with medical treatment (or cardiac resynchronization therapy), including 6 patients ≥10 years from ES diagnosis (up to 14 years). In total, 61 other patients (52%) developed refractory heart failure to disabling New York Heart Association functional classes III/IV (5.2%/year); 67% have survived, including 31 with heart transplant. Of the 118 ES patients, 21 had appropriate implantable cardioverter-defibrillator (ICD) therapy terminating potentially lethal tachyarrhythmias, with no difference in frequency of events in patients with EF 35% to 49% versus EF <35% (17% vs. 19%; p = 0.80). With all available treatment modalities, ES-related mortality was 1.9%/year, with 10-year survival of 85% (95% confidence interval: 77% to 94%). Mortality was 4-fold lower than previously reported for ES (8.0%/year), but exceeded 10-fold HCM with preserved EF (0.2%/year; p < 0.001). CONCLUSIONS:Although ES remains an important complication of HCM, contemporary treatment strategies, including ICDs and heart transplant, are associated with significantly lower mortality than previously considered. Primary prevention ICDs should be considered when EF is <50% in HCM. Rapid heart failure progression is not an inevitable consequence of ES, and some patients experience extended periods of clinical stability.

Background The relation of sex to clinical presentation and course in hypertrophic cardiomyopathy (HCM) remains incompletely resolved. We assessed differences in clinical outcomes between men and women within our large HCM cohort. Methods and Results Of 2123 consecutive patients, a minority (38%) were women who were diagnosed with HCM at older ages or referred for subspecialty evaluation later than men (50±19 versus 44±16 and 55±18 versus 49±16; P<0.001). Women more commonly developed advanced New York Heart Association class III/IV symptoms (53% versus 35% in men; P<0.001), predominantly secondary to outflow obstruction. While end-stage heart failure with systolic dysfunction (ejection fraction <50%) was similar in men (5% versus 4% in women; P=0.33), women were 3-fold more likely to develop heart failure with preserved systolic function (7.5% versus 2.6%; P=0.002). Sudden death events terminated by defibrillator therapy were similar in women (0.9%/year) versus men (1.0%/year; hazard ratio, 0.92; 95% CI, 0.6-1.5; P=0.73). HCM mortality was uncommon, with identical rates in both sexes (0.3%/year; hazard ratio, 1.5; 95% CI, 0.7-3.4;, P=0.25). Age-adjusted all-cause mortality also did not differ between women and men (1.7% versus 1.3%/year; hazard ratio, 1.32; 95% CI, 0.92-1.91; P=0.13). Conclusions Survival was not less favorable in women with HCM. Contemporary treatments including surgical myectomy to reverse heart failure and defibrillators to prevent sudden death, were effective in both sexes contributing to low mortality. However, despite more frequent outflow obstruction, women with HCM are underrecognized and referred to centers later than men, often with more advanced heart failure. Greater awareness of HCM in women should lead to earlier diagnosis and treatment, with implications for improved quality of life.

IMPORTANCE:Strategies for reliable selection of high-risk patients with hypertrophic cardiomyopathy (HCM) for prevention of sudden cardiac death (SCD) with implantable cardioverter/defibrillators (ICDs) are incompletely resolved. OBJECTIVE:To assess the reliability of SCD prediction methods leading to prophylactic ICD recommendations to reduce the number of SCDs occurring in patients with HCM. DESIGN, SETTING, AND PARTICIPANTS:In this observational longitudinal study, 2094 predominantly adult patients with HCM consecutively evaluated over 17 years in a large HCM clinical center were studied. All patients underwent prospective ICD decision making relying on individual major risk markers derived from the HCM literature and an enhanced American College of Cardiology/American Heart Association (ACC/AHA) guidelines-based risk factor algorithm with complete clinical outcome follow-up. Data were collected from June 2017 to February 2018, and data were analyzed from February to July 2018. MAIN OUTCOMES AND MEASURES:Arrhythmic SCD or appropriate ICD intervention for ventricular tachycardia or ventricular fibrillation. RESULTS:Of the 2094 study patients, 1313 (62.7%) were male, and the mean (SD) age was 51 (17) years. Of 527 patients with primary prevention ICDs implanted based on 1 or more major risk markers, 82 (15.6%) experienced device therapy-terminated ventricular tachycardia or ventricular fibrillation episodes, which exceeded the 5 HCM-related SCDs occurring among 1567 patients without ICDs (0.3%), including 2 who declined device therapy, by 49-fold (95% CI, 20-119; P = .001). Cumulative 5-year probability of an appropriate ICD intervention was 10.5% (95% CI, 8.0-13.5). The enhanced ACC/AHA clinical risk factor strategy was highly sensitive for predicting SCD events (range, 87%-95%) but less specific for identifying patients without SCD events (78%). The C statistic calculated for enhanced ACC/AHA guidelines was 0.81 (95% CI, 0.77-0.85), demonstrating good discrimination between patients who did or did not experience an SCD event. Compared with enhanced ACC/AHA risk factors, the European Society of Cardiology risk score retrospectively applied to the study patients was much less sensitive than the ACC/AHA criteria (34% [95% CI, 22-44] vs 95% [95% CI, 89-99]), consistent with recognizing fewer high-risk patients. CONCLUSIONS AND RELEVANCE:A systematic enhanced ACC/AHA guideline and practice-based risk factor strategy prospectively predicted SCD events in nearly all at-risk patients with HCM, resulting in prophylactically implanted ICDs that prevented many catastrophic arrhythmic events in this at-risk population.