Abstract 12853: Predicting Sudden Cardiac Death with Exercise-Stress Test - Combining Cardiorespiratory Fitness with Myocardial Ischemia - A Prospective Population-Based Cohort Study
Objective: To investigate how exercise-stress test can be used to assess more accurately the risk of sudden cardiac death (SCD). Low cardiorespiratory fitness (CRF) and exercise-induced myocardial ischemia in electrocardiogram have previously been shown to increase the risk of SCD. More information is needed in how these risk factors when combined can be used to assess the risk of SCD.
Methods: A total of 2328 randomly selected men aged 42-60 in Kuopio, Finland, participated in this population based follow-up study. At baseline (1984-89) exercise stress test was performed and a large amount of risk factors where collected. The population was divided into four groups according to CRF (Metabolic equivalent (MET) 8 as cut-off point) and the presence of exercise-induced myocardial ischemia in electrocardiogram (defined as atleast 1.0mm ST depression). Cox Regression analysis was used to calculate the risk ratio. SCD was defined as cardiac death within 24 hours after onset of symptoms.
Results: During the mean follow-up time of 19 years 165 SCDs occurred. The risk of SCD was considerably higher in the men who had low CRF together with the presence of exercise-induced myocardial ischemia. The risk ratio was 4.8 (95% CI 2.9 - 7.9), after adjusting for conventional risk factors. As a continuous variable 1 MET increase in CRF was related to a decreased risk of SCD by 19% (p<0.001). The results remained when SCD was defined as 1h after onset of symptoms. Figure 1 is a Kaplan-Meier plot of the cumulative incidence of SCD divided into risk groups 1. High CRF and no ischemia 2. Low CRF and no ischemia 3. High CRF and ischemia 4. Low CRF and ischemia.
Conclusion: By combining these risk factors derived from exercise-stress test, more accurate risk assessment can be made. On basis of these findings this high risk combination of low CRF and exercise-induced myocardial ischemia should be taken into account when considering treatment for patients in risk of SCD.
- © 2011 by American Heart Association, Inc.