Related Experiment Videos
Impaired left ventricular filling dynamics during percutaneous transluminal angioplasty for coronary artery disease
Insights
Brief coronary artery occlusion during angioplasty significantly reduces global left ventricular filling rates. This occlusion also causes significant asynchrony in regional filling and contraction, impacting overall heart function.
Area of Science:
- Cardiology
- Cardiovascular Physiology
Background:
- Left ventricular (LV) filling dynamics are crucial for cardiac function.
- Understanding the immediate effects of coronary occlusion is vital for managing acute ischemic events.
Purpose of the Study:
- To investigate the impact of brief coronary artery occlusion on global and regional LV filling rates.
- To assess the development of contractile and filling asynchrony during acute ischemia.
Main Methods:
- Studied 10 patients undergoing angioplasty without prior myocardial infarction.
- Measured high-fidelity LV pressure and volume using angiography.
- Analyzed segmental wall motion and peak filling rates at various time points during coronary occlusion.
Main Results:
- Global peak LV filling rate significantly decreased after 20 and 50 seconds of occlusion.
- Significant increases in filling asynchrony (sigma delta t1) and contraction asynchrony (sigma delta t2) were observed.
- Negative correlations found between global peak filling rate and both asynchrony measures.
Conclusions:
- Brief coronary occlusion markedly impairs LV diastolic function.
- Acute ischemia induces significant mechanical dyssynchrony in both filling and contraction.
- These findings highlight the rapid detrimental effects of ischemia on LV mechanics.
Abstract:
The effects of brief periods of major coronary artery occlusion on global and regional peak left ventricular (LV) filling rates were studied during angioplasty in 10 patients. No patient had had a previous myocardial infarction. High-fidelity LV pressure and volume were determined by angiography before and 20 and 50 seconds after the onset of transluminal coronary occlusion and soon after the last balloon inflation. Segmental wall motion was analyzed frame by frame along 20 hemiaxes. Global peak filling rate decreased significantly both after 20 (29%, p less than 0.05) and 50 seconds (27%, p less than 0.05) from the onset of the occlusion. The term sigma delta t1 was defined as the sum of the absolute values of the time differences from the occurrence of global peak filling rate and the segmental peak filling rate in 20 segments. This variable increased significantly during both periods of transluminal occlusion (by 73% and by 72% [both p less than 0.005], respectively), indicating asynchrony in the occurrence of regional peak filling rate. Simultaneously, the sum of intervals between aortic valve closure (end systole) and occurrence of peak segmental shortening, sigma delta t2, measured in the 20 segments, increased by 63% after 20 seconds and by 87% after 50 seconds (both p less than 0.005), showing major asynchrony in segmental contraction. A significant negative correlation was found between global peak filling rate and both sigma delta t1 and sigma delta t2 (r = 0.64, p less than 0.001 and r = 0.70, p less than 0.0001, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)