RIGHT-VENTRICULAR DYSFUNCTION DURING CORONARY-ARTERY OCCLUSION - PRESSURE-VOLUME ANALYSIS USING CONDUCTANCE CATHETERS DURING CORONARY ANGIOPLASTY

Objective-To study the effects of coronary artery occlusion on the pre ssure-volume relations of the right ventricle. Design-Right ventricula r pressure-volume cycles were studied using conductance catheters and micromanometers in 19 subjects undergoing coronary angioplasty in a te rtiary referral cardiac centre. Results-Catheter occlusions of either the left: anterior descending coronary artery or the right coronary ar tery were associated with a decline in stroke work (mean change (SD): left -13.3(15.8)%, p = 0.008; right -13.5(16.5)%, p = 0.04). Two patte rns of change were evident: an upward shift usually associated with oc clusion in the left coronary artery, and a rightward shift in the righ t coronary artery. In the former there was an increase in maximum vent ricular volume (mean change: 3.0(2.7)%, p = 0.004) and in minimum vent ricular volume (mean change: 2.3(2.7)%, p = 0.01) and a fall in peak p ressure (mean change: -4.8(5.1)%, p = 0.04). In the latter there was a n increase in peak pressure (mean change 9.9(16.3)%, p = 0.04) and an increase in minimum ventricular volume (mean change 3.7(5.0)%, p = 0.0 2) leading to a fall in stroke volume (mean change -13.3(15.8)%, p = 0 .008). Conclusions-Occlusion of the left anterior descending coronary artery or the right coronary artery is associated with a decline in ri ght ventricular work. However, different patterns of change in indices of preload and afterload lead to different effects on overall right v entricular pump function.