The utility of heart rate recovery to predict right ventricular systolic dysfunction in patients with obesity.

Objective: Obesity is a nutritional disorder, which is associated with impaired left and right ventricular function. Impaired heart rate recovery (HRR) following a treadmill exercise test is an indicator of cardiovascular mortality. We investigated the utility of impaired HRR on the tissue Doppler imaging (TDI) echocardiographic estimates of left and right ventricular function in an obese/overweight cohort.

Methods: Eighty consecutive patients with body mass index >27 kg/m(2) were evaluated for their post exercise HRR in this cross-sectional study. The results were compared with the tissue Doppler and conventional echocardiographic findings of the same cohort. Tricuspid annular TDI peak systolic velocities (RVs) were evaluated with receiver operating characteristic (ROC) analysis to predict the insufficient heart rate recovery (18/min or less). Logistic regression analysis was used to identify the independent predictors of significant right ventricular systolic dysfunction (RVs <10 cm/sec) among the clinical and echocardiographic parameters.

Results: There was a positive correlation between HRR and tricuspid annulus peak systolic velocity, exercise distance, and METs. The patients with impaired HRR at post-exercise first minute had lower exercise distance (p<0.0001), METs (p=0.001), RVs (p=0.037), and basal septal peak systolic velocity (p=0.041) than the patients with normal HRR. A tricuspid annulus TDI peak systolic velocity of 10 cm/sec predicted post-exercise preserved HRR with 70% sensitivity and 55% specificity with ROC analysis (AUC=0.638, 95% CI- 0.509-0.767, p=0.037). The subjects with tricuspid annulus peak systolic velocity (RVs) <10cm/sec were found to have larger body mass indices, impaired post-exercise first minute HRR, shorter total exercise distance, and lower total METs than the subjects with tricuspid annulus peak systolic velocity >10cm/sec. Impaired HRR and septum TDI late diastolic velocity were found as the independent predictors of right ventricular systolic function (RVs<10cm/sec) by logistic regression analysis.

Conclusion: Post-exercise first minute impaired HRR is associated with right ventricular systolic dysfunction in obese patients. Both HRR and right ventricular systolic function correlate well with the exercise distance and METs. Obese patients with impaired HRR should be evaluated with echocardiography to assess their right ventricular systolic function.