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.