Pulmonary to Systemic Flow Ratio (Qp/Qs) in Dilated Cardiomyopathy, Mitral Valve Disease and Patent Ductus Arteriosus Affected Dogs

Abstract

The study was designed to determine pulmonary to systemic flow ratio (Qp/Qs) by Doppler echocardiography in Dilated cardiomyopathy (DCM), Mitral valve disease (MVD) and Patent ductus arteriosus (PDA) affected dogs.  Dilated cardiomyopathy, mitral valve disease and Patent ductus arteriosus were diagnosed by Doppler echocardiography and in these affected dogs pulmonary artery diameter, peak pulmonary artery velocity, pulmonary velocity time interval, aortic diameter, peak aortic flow, aortic velocity time interval were recorded.  The mean values of Qp/Qs ratio in DCM and MVD were 1.16±0.21 and 0.72±0.31 respectively. The mean values of Qp, Qs and Qp/Qs ratio was 25.62±4.47, 14.99±5.02 and 1.2±0.16 respectively in PDA affected dogs. Increase in Qp may be observed due to pulmonary over circulation, these leading to an increase in Qp/Qs ratio.  Left to right shunting associated with intracardiac shunts in PDA leads to above mentioned condition. The combination of pulmonary to systemic flow ratio (Qp/Qs) with Doppler parameters, offers a striking approach for the assessment of intra cardiac shunt severity in dogs.  Further, the present method is rapid, easy and non-invasive and aids in early diagnosis.