611 Relations of Left Ventricular Hypertrophy and Impaired Heart Rate Recovery After Treadmill Test

Background: Heart rate recovery (HRR) after exercise is known as a predictor of cardiac death in patients with heart disease. The mechanism is not fully understood, although a parasympathetic mechanism has been reported. An attenuated HRR may be considered to be due to sympathetic activation. Sympathetic activation has been suggested to contribute to left ventricular hypertrophy (LVH). This study aimed at assessing relation with between LVH and impaired HRR. Methods: 693 consecutive patients without a history of heart failure or valvular disease were enrolled. The patients were undergoing symptom-limited exercise testing, echocardiography. Abnormal HRR was defined as the difference in heat rate between peak exercise and 1, 2 minutes later (1 minute: a value < 18 beats/min, 2 minutes: a value < 42 beats/min were considered abnormal). LVH defined left ventricular mass index (LVMI) values of >104 g/m2 in women and >116 g/m2 in men. Results: Abnormal HRR at 2 minutes were more common in the LVH group as compared to the non-LVH group (47.8% versus 25.6%, p=0.001). However, there were no differences between the groups in the percentage of patients with abnormal HRR at 1 minute (10.1% versus 8.2 %, p=0.54). LVMI was significantly correlated with HRR at 1 minute (r = - 0.116, P = .0002), HRR at 2 minutes (r = - 0.156, P<.0001), but with a weak association. Conclusion: Abnormal HRR at 2 minutes was associated with the presence of LVH. LVMI might be related to the impaired HRR after exercise test.