Contemporary Natural History and Management of Nonobstructive Hypertrophic Cardiomyopathy

n/

Clinical Spectrum, Therapeutic Options, and Outcome of Advanced Heart Failure in Hypertrophic Cardiomyopathy

Background— The clinical course of patients with hypertrophic cardiomyopathy and advanced heart failure (HF) subtended by progressive left ventricular dysfunction has received limited attention. Our aim was to assess the outcome of HF and impact of treatment options including the implantable cardioverter-defibrillator and heart transplantation (HT) in patients with hypertrophic cardiomyopathy evaluated at 2 Italian referral centers >3 decades. Methods and Results— All-cause mortality and a combined end point including death, HT, or appropriate implantable cardioverter-defibrillator shock were assessed in 71 consecutive patients with HF not related to outflow obstruction (7% of the entire hypertrophic cardiomyopathy cohort) followed up for 6.1±6.9 years after development of New York Heart Association class III to IV symptoms. At enrollment, left ventricular ejection fraction was 50% in 16; all had restrictive left ventricular filling. During follow-up, 35 patients died (49%%; 5-year rate, 49%) and 53 met the combined end point (75%; 5-year rate, 62%). Most events occurred in the 3 years after HF onset (17% per year compared with only 3% per year subsequently). Appropriate implantable cardioverter-defibrillator shocks occurred in 11 of 34 implanted patients. Of 37 patients evaluated for HT, 14 were transplanted, 10 listed, and 13 excluded; 2 early post-HT deaths occurred in patients with elevated pulmonary vascular resistance. Eleven of the 14 HT patients were alive at 10±8 years. Conclusions— In hypertrophic cardiomyopathy, advanced HF not associated with outflow obstruction portends a severely unfavorable prognosis, particularly in the first 3 years after onset of symptoms, despite frequently preserved systolic function in about one quarter of the patients. Outcome of HT is favorable but requires early consideration, as the window of opportunity may be short

Long-term outcomes of pediatric-onset hypertrophic cardiomyopathy and age-specific risk factors for lethal arrhythmic events

IMPORTANCE Predictors of lethal arrhythmic events (LAEs) after a pediatric diagnosis of hypertrophic cardiomyopathy (HCM) are unresolved. Existing algorithms for risk stratification are limited to patients older than 16 years because of a lack of data on younger individuals. OBJECTIVE To describe the long-term outcome of pediatric-onset HCM and identify age-specific arrhythmic risk factors. DESIGN, SETTING, AND PARTICIPANTS This study assessed patients with pediatric-onset hypertrophic cardiomyopathy diagnosed from 1974 to 2016 in 2 national referral centers for cardiomyopathies in Florence, Italy. Patients with metabolic and syndromic disease were excluded. EXPOSURES Patients were assessed at 1-year intervals, or more often, if their clinical condition required. MAIN OUTCOMES AND MEASURES Lethal arrhythmic events (LAEs) and death related to heart failure. RESULTS Of 1644 patients with HCM, 100 (6.1%) were 1 to 16 years old at diagnosis (median [interquartile range], 12.2 [7.3-14.1] years). Of these, 63 (63.0%) were boys. Forty-two of the 100 patients (42.0%) were symptomatic (defined as an New York Heart Association classification higher than 1 or a Ross score greater than 2). The yield of sarcomere gene testing was 55 of 70 patients (79%). During a median of 9.2 years during which a mean of 1229 patients were treated per year, 24 of 100 patients (24.0%) experienced cardiac events (1.9%per year), including 19 LAEs and 5 heart failure-related events (3 deaths and 2 heart transplants). Lethal arrhythmic events occurred at a mean (SD) age of 23.1 (11.5) years. Two survivors of LAEs with symptoms of heart failure experienced recurrent cardiac arrest despite an implantable cardioverter defibrillator. Risk of LAE was associated with symptoms at onset (hazard ratio [HR], 8.2; 95%CI, 1.5-68.4; P = .02) and Troponin I or Troponin T gene mutations (HR, 4.1; 95%CI, 0.9-36.5; P = .06). Adult HCM risk predictors performed poorly in this population. Data analysis occurred from December 2016 to October 2017. CONCLUSIONS AND RELEVANCE Pediatric-onset HCM is rare and associated with adverse outcomes driven mainly by arrhythmic events. Risk extends well beyond adolescence, which calls for unchanged clinical surveillance into adulthood. In this study, predictors of adverse outcomes differ from those of adult populations with HCM. In secondary prevention, the implantable cardioverter defibrillator did not confer absolute protection in the presence of limiting symptoms of heart failure