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 pressure-volume relations of the right ventricle. DESIGN: Right ventricular pressure-volume cycles were studied using conductance catheters and micromanometers in 19 subjects undergoing coronary angioplasty in a tertiary referral cardiac centre. RESULTS: Catheter occlusions of either the left anterior descending coronary artery or the right coronary artery 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 patterns of change were evident: an upward shift usually associated with occlusion in the left coronary artery, and a rightward shift in the right coronary artery. In the former there was an increase in maximum ventricular volume (mean change: 3.0(2.7)%, p = 0.004) and in minimum ventricular volume (mean change: 2.3(2.7)%, p = 0.01) and a fall in peak pressure (mean change: -4.8 (5.1)%, p = 0.04). In the latter there was an 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 = 0.02) 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 right ventricular work. However, different patterns of change in indices of preload and afterload lead to different effects on overall right ventricular pump function.