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Little is known if heart rate responses during and after exercise test may be associated with the risk of sudden cardiac death (SCD). Our aim was to determine if exercise heart rate reserve and recovery, providing non-invasive indices, may predict SCD risk in general male population.We evaluated the impact of delayed heart rate reserve and slow heart rate recovery and the risk of SCD in the Kuopio Ischemic Heart Disease prospective cohort study of randomly selected 1967 men aged 42-61 years at recruitment. Heart rate reserve was calculated as the difference between the maximal attained heart rate and resting heart rate, whereas heart rate recovery was defined as maximal heart rate minus the heart rate measured at 2 min of recovery, on a symptom-limited cardiopulmonary exercise testing.During a median follow-up interval of 25 years, 209 events of SCD occurred. The age and examination adjusted relative hazards of SCD were in the lowest third of heart rate reserve 3.86 (95% confidence interval (CI) 2.56-5.80, p 0.001) and the lowest third of heart rate recovery 2.86 (95% CI 1.95-4.20, p 0.001) as compared to men in the highest third of heart rate reserve and heart rate recovery, respectively. After adjusting for potential confounders, the respective relative hazards were 1.96 (95% CI 1.24-3.12) and 1.75 (95% CI 1.16-2.64). Each unit increment (1 beat/min) in heart rate reserve and heart rate recovery decreased the incidence of SCD by 1-2%.Delayed exercise heart rate reserve and slow heart rate recovery predicted the risk of SCD, suggesting that heart rate responses may be associated with an increased risk for SCD in general population.

Little is known about exercise cardiac power (ECP), defined as the ratio of directly measured maximal oxygen uptake with peak systolic blood pressure during exercise, on heart failure (HF) risk. We examined the association of ECP and the risk of HF.This was a population-based cohort study of 2351 men from eastern Finland. The average time to follow-up was 25 years. Participants participated at baseline in an exercise stress test. A total of 313 cases of HF occurred.Men with low ECP (9.84 mL/mmHg, the lowest quartile) had a 2.37-fold (95% confidence interval (95%CI): 1.68-3.35, p0.0001) hazards ratio of HF as compared with men with high ECP (13.92 mL/mmHg, the highest quartile), after adjusting for age. Low ECP was associated with a 1.96-fold risk (95%CI: 1.38-2.78, p0.001) of HF after additional adjustment for conventional risk factors. After further adjustment for left ventricular hypertrophy, the results hardly changed (hazards ratio = 1.87, 95%CI: 1.31-2.66, p0.001). One SD increase in ECP (3.16 mL/mmHg) was associated with a decreased risk of HF by 28% (95%CI: 17%-37%).ECP provides a noninvasive and easily available measure from cardiopulmonary exercise tests in predicting HF. However, ECP did not provide additional value over maximal oxygen uptake

The aim of this study was to investigate whether information on both cardiorespiratory fitness (CRF) and exercise-induced ST segment depression improves the prediction of sudden cardiac death (SCD) in men.The study was based on a population sample of 2328 men aged 42-60 years, who were followed up for on average 19 years. CRF was assessed with maximal exercise test using respiratory gas analysis, expressed in metabolic equivalents (METs) and dichotomised at eight METs. Exercise-induced ST segment depression was defined as 1 mm ST segment depression in ECG.Altogether 165 SCDs occurred during the follow-up. Men with low CRF (8 METs) and exercise-induced ST segment depression had 4.8-fold (95% CI 2.9 to 7.9) higher risk of SCD than men with high CRF and without exercise-induced ST segment depression (p=0.013 for interaction) after adjustment for other cardiovascular risk factors. Men with high CRF and exercise-induced ST segment depression did not have a statistically significantly higher risk of SCD (HR 1.9, 95% CI 0.9 to 3.8) than men with high CRF and without exercise-induced ST segment depression.The combination of low CRF and exercise-induced ST segment depression was associated with a markedly increased risk of SCD in men.

Background We studied the independent and joint associations of leisure-time physical activity (LTPA) and cardiorespiratory fitness (CRF) with the risk of sudden cardiac death (SCD) among middle-aged men. Methods The participants were 2656 randomly selected men aged 42-60 years at baseline who were followed for 19 years. LTPA was assessed using a questionnaire modified from the Minnesota LTPA Questionnaire and CRF using a respiratory gas exchange analyzer during maximal exercise test. The participants were divided into 4 groups according to the level of LTPA and CRF dichotomized at the lowest tertiles. Results Men with low CRF had a 1.6 (95% confidence interval [CI], 1.1-2.3; P = 0.011) times higher risk of SCD than men with high CRF after adjustment for conventional risk factors. Men with low LTPA had a 1.4 (95% CI, 1.0-2.0; P = 0.032) times higher SCD risk than men with high LTPA after these adjustments. Men with low CRF and low LTPA had a 2.2 (95% CI, 1.4-3.3) times higher SCD risk than men with high CRF and high LTPA adjusting for conventional risk factors ( P = 0.044 for interaction). Conclusions It seems that low LTPA increases the risk of SCD particularly among men with low CRF but the level of LTPA does not modify the incidence of SCD among men with high CRF.