Global longitudinal strain is associated with heart failure outcomes in hypertrophic cardiomyopathy.

OBJECTIVE: We hypothesised that abnormal global longitudinal strain (GLS) would predict outcome in hypertrophic cardiomyopathy (HCM) better than current echocardiographic measures. METHODS: Retrospective analysis of risk markers in relation to outcomes in 472 patients with HCM at a single tertiary institution (2006-2012). Exclusion criteria were left ventricular (LV) hypertrophy of other origin, patients in atrial fibrillation, lost to follow-up and insufficient image quality to perform strain analysis. Standardised echocardiogram recordings were reviewed and standard variables and LV GLS were measured. The primary end-point included all cardiac deaths, appropriate defibrillator shocks and heart failure (HF) admissions. The secondary end-point was death by HF and admissions related to HF. RESULTS: Mean age was 50.0±15.0 years; 322 (68%) were men. At a median of 4.3 years (IQR 0.1-7.8) follow-up, 21 (4.4%) patients experienced cardiovascular death: 6 (1.3%) died from HF, 13 (2.7%) had sudden cardiac death and 2 (0.4%) died secondary to stroke. Four (0.8%) patients experienced appropriate defibrillator shock, and 13 (2.7%) were admitted for HF. On multivariate Fine-Gray proportional hazard analyses, GLS was significantly associated with the primary end-point (HR=0.90, 95% CI 0.83 to 0.98, p=0.018) independently of age, maximal provoked LV outflow-tract gradient and LV end-systolic volume. Moreover, GLS was particularly associated with the secondary end-point (HR=0.82, 95% CI 0.75 to 0.90, p<0.0001) independently of age, previous atrial fibrillation, New York Heart Association (NYHA) class III-IV, LV end-systolic volume, E/E', and outflow-tract gradient. Survival curves confirmed that GLS was associated with HF events (GLS <15.6%, p=0.0035). CONCLUSIONS: In patients with HCM, reduced GLS is an independent factor associated with poor cardiac outcomes, and particularly HF outcomes.

A validation study of the 2003 American College of Cardiology/European Society of Cardiology and 2011 American College of Cardiology Foundation/American Heart Association risk stratification and treatment algorithms for sudden cardiac death in patients with hypertrophic cardiomyopathy.

AIMS: Sudden cardiac death (SCD) is a common mode of death in hypertrophic cardiomyopathy (HCM), but identification of patients who are at a high risk of SCD is challenging as current risk stratification guidelines have never been formally validated. The objective of this study was to assess the power of the 2003 American College of Cardiology (ACC)/European Society of Cardiology (ESC) and 2011 ACC Foundation (ACCF)/American Heart Association (AHA) SCD risk stratification algorithms to distinguish high risk patients who might be eligible for an implantable cardioverter defibrillator (ICD) from low risk individuals. METHODS AND RESULTS: We studied 1606 consecutively evaluated HCM patients in an observational, retrospective cohort study. Five risk factors (RF) for SCD were assessed: non-sustained ventricular tachycardia, severe left ventricular hypertrophy, family history of SCD, unexplained syncope and abnormal blood pressure response to exercise. During a follow-up period of 11 712 patient years (median 6.6 years), SCD/appropriate ICD shock occurred in 20 (3%) of 660 patients without RF (annual rate 0.45%), 31 (4.8%) of 636 patients with 1 RF (annual rate 0.65%), 27 (10.8%) of 249 patients with 2 RF (annual rate 1.3%), 7 (13.7%) of 51 patients with 3 RF (annual rate 1.9%) and 4 (40%) of 10 patients with ≥4 RF (annual rate 5.0%). The risk of SCD increased with multiple RF (2 RF: HR 2.87, p≤0.001; 3 RF: HR 4.32, p=0.001; ≥4 RF: HR 11.37, p<0.0001), but not with a single RF (HR 1.43 p=0.21). The area under time-dependent receiver operating characteristic curves (representing the probability of correctly identifying a patient at risk of SCD on the basis of RF profile) was 0.63 at 1 year and 0.64 at 5 years for the 2003 ACC/ESC algorithm and 0.61 at 1 year and 0.63 at 5 years for the 2011 ACCF/AHA algorithm. CONCLUSIONS: The risk of SCD increases with the aggregation of RF. The 2003 ACC/ESC and 2011 ACCF/AHA guidelines distinguish high from low risk individuals with limited power.

Multicenter study of the efficacy and safety of disopyramide in obstructive hypertrophic cardiomyopathy.

OBJECTIVES: In this study we assessed the long-term efficacy and safety of disopyramide for patients with obstructive hypertrophic cardiomyopathy (HCM). BACKGROUND: It has been reported that disopyramide may reduce left ventricular outflow gradient and improve symptoms in patients with HCM. However, long-term efficacy and safety of disopyramide has not been shown in a large cohort. METHODS: Clinical and echocardiographic data were evaluated in 118 obstructive HCM patients treated with disopyramide at 4 HCM treatment centers. Mortality in the disopyramide-treated patients was compared with 373 obstructive HCM patients not treated with disopyramide. RESULTS: Patients were followed with disopyramide for 3.1 +/- 2.6 years; dose 432 +/- 181 mg/day (97% also received beta-blockers). Seventy-eight patients (66%) were maintained with disopyramide without the necessity for major non-pharmacologic intervention with surgical myectomy, alcohol ablation, or pacing; outflow gradient at rest decreased from 75 +/- 33 to 40 +/- 32 mm Hg (p < 0.0001) and mean New York Heart Association functional class from 2.3 +/- 0.7 to 1.7 +/- 0.6 (p < 0.0001). Forty other patients (34%) could not be satisfactorily managed with disopyramide and required major invasive interventions because of inadequate symptom and gradient control or vagolytic side effects. All-cause annual cardiac death rate between disopyramide and non-disopyramide-treated patients did not differ significantly, 1.4% versus 2.6%/year (p = 0.07). There was also no difference in sudden death rate, 1.0%/year versus 1.8%/year (p = 0.08). CONCLUSIONS: Two-thirds of obstructed HCM patients treated with disopyramide could be managed medically with amelioration of symptoms and about 50% reduction in subaortic gradient over >/=3 years. Disopyramide therapy does not appear to be proarrhythmic in HCM and should be considered before proceeding to surgical myectomy or alternate strategies.