Sudden cardiac death: investigation of the classical risk factors in a community-based hypertrophic cardiomyopathy cohort.

INTRODUCTION: The identification of high-risk patients in hypertrophic cardiomyopathy (HCM) is still a challenge. The classical clinical risk factors for sudden death have been reported by studies coming from referral HCM cohorts. So far, other studies of community-based HCM populations have not managed to identify risk factors for sudden cardiac death. The aim of the present study was to determine the clinical course of the disease in a community-based HCM population, as well as to identify the clinical factors of sudden death in such a population. METHODS: Three hundred four (304) consecutive HCM patients (202 males, age 48 ± 18.5 years) from 280 different families were assessed. Referral was based on disease diagnosis, irrespective of clinical status or treatment needs. All patients were examined clinically, echocardiographically, by 24h ambulatory electrocardiographic monitoring, and by cardiopulmonary exercise testing at regular intervals, for a period of 56.4 ± 29.9 months. RESULTS: Most patients (n=264/304, 87.2%) were in New York Heart Association functional class I or II. The disease was familial in 60.5%. At initial examination, maximum left ventricular wall thickness was 19 ± 4.4 mm and a left ventricular outflow gradient >30 mmHg was present in 30.9% patients. The annual sudden death mortality was 1.2%. Familial sudden death, non-sustained ventricular tachycardia, severe left ventricular hypertrophy >30 mm, and young age were predictors of sudden cardiac death. CONCLUSIONS: In this community-based HCM population, the risk factors for sudden death were similar to those found in referral cohorts.

ST segment "hump" during exercise testing and the risk of sudden cardiac death in patients with hypertrophic cardiomyopathy.

BACKGROUND: The appearance of a discrete upward deflection of the ST segment termed "the ST hump sign" (STHS) during exercise testing has been associated with resting hypertension and exaggerated blood pressure response to exercise. OBJECTIVE: We investigated the prevalence and clinical significance of this sign in a population of patients with hypertrophic cardiomyopathy. METHODS: Eighty-one patients with hypertrophic cardiomyopathy (HCM) who underwent cardiopulmonary exercise testing were followed in a retrospective cohort study for a mean period of 5.3 years. RESULTS: The appearance of the STHS at the peak of exercise testing was observed in 42 patients (52%), particularly in the inferior and the lateral leads. Patients with the STHS had higher fractional shortening and maximum left ventricular wall thickness and exhibited more frequently outflow tract gradient >30 mmHg at rest. Furthermore, the presence of STHS was a strong independent predictor of the risk of sudden cardiac death (SCD), as the latter occurred in eight of the patients with this sign (8/42, 19%) and in none of the patients without it (0/39, 0%) (P < 0.001). CONCLUSION: The appearance of a "hump" at the ST segment during exercise testing appears to be a risk factor for SCD in patients with HCM. However, further studies are necessary to validate this finding in larger populations and to elucidate the mechanism of the appearance of the "hump."

The effect of a high carbohydrate meal on endurance running capacity.

This study examined the effects of a pre-exercise meal and a carbohydrate-electrolyte solution on endurance running capacity. Ten men performed 3 treadmill runs at 70% VO2max to exhaustion after consuming (a) a carbohydrate meal 3 h before exercise and a carbohydrate-electrolyte solution during exercise (M + C); or (b) the carbohydrate meal 3 h before exercise and water during exercise (M + W); or (c) a liquid placebo 3 h before exercise and water during exercise (P + W). Exercise time was longer in M + C (125.1 +/- 5.3 min; mean +/- SE) and M + W (111.9 +/- 5.6 min) compared with P + W (102.9 +/- 7.9 min; p < .01 and p < .05, respectively), and longer in M + C compared with M + W (p < .05). Serum insulin concentration at the start of exercise and carbohydrate oxidation rates during the first hour of exercise were higher, whereas plasma FFA concentrations throughout exercise were lower in M + W and M + C than in P + W (p < .01). A carbohydrate meal before exercise at 70% VO2max improved endurance running capacity; however, the combination of the meal and a carbohydrate-electrolyte solution during exercise further improved endurance running capacity.