Prognostic Value of Heart Rate Increase at Onset of Exercise Testing

Abstract

Background-The initial response of heart rate to dynamic exercise has been proposed as having prognostic value in limited studies that have used modalities other than the treadmill. Our aim was to evaluate the prognostic value of early heart rate parameters in patients referred for routine clinical treadmill testing. Methods and Results-The heart rate rise at the onset of exercise was measured in 1959 patients referred for clinical treadmill testing at the Palo Alto (Calif) Veterans Affairs Medical Center from 1997 to 2004. Multivariable Cox survival analysis was performed for 197 all-cause and 74 cardiovascular deaths that accrued during a mean follow-up of 5.4Ϯ2.1 years. Decreased heart rate changes at all initial relative exercise workloads were associated with significantly increased all-cause mortality. The heart rate rise at one-third total exercise capacity, however, was the only early heart rate variable that significantly predicted both all-cause and cardiovascular risk after adjustment for confounders. Failing to reach 1 SD in the heart rate rise at one-third total exercise capacity was associated with a 28% increased all-cause mortality rate (hazard ratio, 0.72; 95% CI, 0.61 to 0.85; PϽ0.001) and a 35% cardiovascular mortality rate (hazard ratio, 0.65; 95% CI, 0.49 to 0.86; Pϭ0.003). Of all heart rate measurements considered (initial and recovery), the heart rate increase at peak exercise was the most powerful predictor of cardiovascular prognosis after adjustment for potential confounders. The Duke treadmill score, however, was superior to all heart rate measurements in the prediction of cardiovascular mortality. Conclusions-In the present study population, a rapid initial heart rate rise was associated with improved survival, but the heart rate increase at peak exercise and other conventional measurements such as exercise capacity and the Duke treadmill score were more powerful predictors of prognosis.

Associação entre transientes inicial e final de frequência cardíaca no teste de exercício

“…The interpretation of this positive association shows that individuals with higher ΔHR tend to have a higher CVA as measured by CVI. Within this perspective, our findings corroborated, at least in part, those described by Leeper et al 14 , who recently demonstrated a better prognosis in individuals with ΔHR ≥12 bpm undergoing symptom-limited treadmill ET. The modest association found in our study may be explained by these authors' argument that the HR response in the 1st minute of exercise may reflect not only exercise-induced vagal withdrawal, but also the magnitude of the adrenergic response to exercise.…”

Low Heart Rates Predict Incident Atrial Fibrillation in Healthy Middle-Aged Men

“…18 The balance between parasympathetic and sympathetic activity is considered to be involved in both the initiation and the maintenance of AF. 19 The present main results-an increased AF risk associated with low HR at moderate exercise in healthy men-might suggest involvement of an inappropriate HR response to exercise with prolonged parasympathetic activation.…”

Decline in Serum Cholinesterase Activities Predicts 2-Year Major Adverse Cardiac Events

“…Supporting this notion, indirect measures of cardiac parasympathetic dysfunction such as elevated resting heart rate, delayed heart rate recovery after exercise and attenuated heart rate increase during exercise have all been shown to be independent predictors for adverse cardiovascular outcome (1)(2)(3). Abnormalities in these parameters (4) have been shown in diverse study populations to be associated with sudden cardiac death (1,5) as well as all-cause mortality (2,3,6,7), but clinically validated biomarkers to assess the parasympathetic system are not yet available. Of note, the parasympathetic neurotransmitter, acetylcholine (ACh), is extremely labile and difficult to use for clinical measurements (8).…”