Degeneration of the Cardiac Nerves

The Valsalva maneuver was performed by a series of eight patients with chronic Chagas' heart disease who had no current evidence nor past history of heart failure. The fact that all the patients showed recovery of arterial pressure during the latter portion of the period of increased airway pressure and exhibited significant overshoot in pressure in the post-straining period of the Valsalva maneuver strongly suggests that reflex activity of arteriolar tone was present. However, slowing of the heart rate was not found in association with the blood pressure overshoot in half of the patients. This abnormal response was observed only in patients in whom atropine sulfate failed to cause an increase in heart rate. These results are interpreted as a further indication of degeneration of autonomic nervous system controlling heart rate in chronic Chagas' heart disease.