Valsalva maneuver in chagasic patients with documented past medical history of acute chagasic myocarditis

Background: We studied the heart rate responses to the Valsalva maneuver in eight patients with documented past medical history of acute Chagas’ disease. Methods: Four patients were studied 8–21 months after the acute episode and four, 58–68 months thereafter (age 25±8.65 years M±S.D.). Seventeen healthy subjects of similar age were included as controls (age 27±7.5 years, P=NS). Results: Baseline heart rate was higher in chagasic patients (88±15 beats/min) compared to controls (69.8±9.8, P=0.001). Maximum heart rate at phase II of the maneuver was also higher (114±16.3 vs. 101.5±9.9, P=0.02). Minimum heart rate at phase IV was, however, not different (57.4±10.4 vs. 63.3±7.3 P=NS). The magnitude of the absolute negative change at phase IV was larger in the chagasic patients, although, not different (−50.8±13.8 vs. −44±13.8, P=NS). The Valsalva index was 1.81±0.26 in the chagasic patients and 1.82±0.42 in the controls (P=NS). Minimum heart rate at phase IV correlated neither with the baseline heart rate (r=−0.28, P=NS) nor with the Valsalva index (r=−0.40, P=NS). The magnitude of the absolute negative change during phase IV correlated with, both, the baseline heart rate (r=−0.80, P<0.01) and the Valsalva index (r=−0.95, P<0.0001). The higher baseline high rate influenced the magnitude of the negative heart rate change, but not the minimum heart rate reached at phase IV. Conclusions: Chagasic patients with proven past medical history of acute Chagas’ disease had unimpaired heart responses to the Valsalva maneuver.