Effect of citric acid on electrocardiographic parameters of broiler chickens with pulmonary hypertension.

To clarify the effect of orally administered citric acid on the electrocardiographic parameters of pulmonary hypertensive broilers, chicks were reared at high altitude and treated with citric acid for 45 days. Increase of cardiac indices such as right ventricle/total ventricles (RV/TV), RV/body weight and TV/body weight ratio was not observed in the treated groups as compared to the control groups. Decrease of S amplitude in the treated groups (leads II, III, aVF) was only significant (P < 0.05) at 45 days of age (leads II, aVF; 1.5 g/l of citric acid). There were significant reductions of T amplitude at 28 (lead aVR) and 36 days (lead aVL) and significant reductions of R wave at 28 (lead aVL, all doses of citric acid) and 45 days of age (lead aVR, 1 and 1.5 g/l citric acid) in the treated groups. The QRS interval was significantly higher at 28 (leads III and aVF), 36 (leads II, III and aVF, 1 g/l citric acid) and 45 days of age (leads II and aVF) in the treated groups. The QT interval was significantly (P < 0.05) increased at 28 and 45 days of age (lead aVL) and the RR interval also showed an increase at 28 (leads aVR and aVL) and 45 (lead aVL) days of age as compared to the controls. Our data indicate that citric acid modulates the induction of pulmonary hypertension at high altitude and this effect is detectable in the electrocardiographic parameters.