MORPHOLOGIC AND FUNCTIONAL CHARACTERIZATION OF CHAGASIC HEART DISEASE IN NON-HUMAN PRIMATES

Chagasic heart disease has been documented in non-human primates, but noninvasive characterization of systolic and diastolic function has not been previously reported. Seventeen seropositive (12 females; mean age, 20) and 13 age- and gender-matched seronegative baboons underwent Doppler echocardiography. Systolic function indices included left ventricular (LV) fractional shortening (FS %), velocity of circumferential fiber shortening (VCF, circ/sec), LV mass index, and left and right ventricular ejection fractions (RVEF %). Diastolic function indices included trans- mitral E-wave, A-wave, E/A ratio, E-deceleration time, and isovolumic relaxation time. Twelve-lead electrocardio- graphic (ECG) recordings were obtained. There were no significant differences between groups for body size or blood pressure. Seropositive and seronegative groups revealed diffuse non-specific T wave changes precluding differentiation; however, tall "P" waves were seen in four seropositive and two seronegative baboons. Four of the 17 (24%) seropositive baboons had decreased FS (25 ± 8% versus 40 ± 5%, P < 0.005) and VCF (1.05 ± 0.36 circ/sec versus 1.84 ± 0.23 circ/sec, P < 0.0001), prolonged isovolumic relaxation time (71 ± 16 msec versus 5 5±9m sec, P < 0.02), and reduced RVEF (44 ± 9% versus 54 ± 4%, P < 0.05), as compared with the other seropositive baboons. We conclude that chagasic heart disease is present in 24% of the naturally infected baboons in this study. ECG evidence of right atrial enlargement was more common in the seropositive animals. There were systolic and diastolic abnormalities of both ventricles. The LV systolic dysfunction may be segmental or diffuse.