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Early changes in wall motion and wall thickness during percutaneous transluminal coronary angioplasty in man
Insights
Percutaneous transluminal coronary angioplasty (PTCA) induced ischemia causes characteristic biphasic wall motion changes, termed the "W" phenomenon. This early indicator aids in understanding myocardial response during coronary interventions.
Area of Science:
- Cardiology
- Medical Imaging
- Physiology
Background:
- Percutaneous transluminal coronary angioplasty (PTCA) involves temporary coronary artery occlusion, mimicking experimental models.
- Understanding myocardial response to ischemia during PTCA is crucial for patient outcomes.
Purpose of the Study:
- To investigate epicardial and segmental wall motion and myocardial thickness during PTCA.
- To identify characteristic changes in cardiac motion and thickness during induced ischemia.
Main Methods:
- Biplane cineradiography with epicardial markers to assess epicardial wall motion.
- Continuous M-mode echocardiography to evaluate septal motion and thickness.
- Left ventricular angiography to analyze segmental wall motion during ischemia.
Main Results:
- Bypass graft occlusion caused biphasic epicardial motion (late systolic lengthening, early diastolic shortening).
- Echocardiography revealed decreased septal systolic thickening and early diastolic notching during occlusion.
- Left ventricular angiography demonstrated a biphasic segmental wall motion pattern ('W' phenomenon) during ischemia.
Conclusions:
- The 'W' phenomenon (biphasic wall motion) is an early and characteristic change during PTCA-induced ischemia.
- These findings enhance understanding of myocardial mechanics during coronary interventions.
- The study highlights the utility of various imaging modalities in assessing cardiac function during PTCA.
Abstract:
Epicardial wall motion, myocardial wall thickness and segmental wall motion during percutaneous transluminal coronary angioplasty, a situation which resembles the experimental abrupt occlusion of a major coronary artery in the animal laboratory, have been studied in patients undergoing the procedure. Epicardial wall motion was analyzed using biplane cineradiography with frame to frame measurements of distances between pairs of radiopaque epicardial markers, placed at the time of previous cardiac surgery in a patient with a stenosis of a coronary artery bypass graft. Bypass graft occlusion led to early onset of biphasic epicardial late systolic lengthening and early diastolic shortening similar to the regional wall motion abnormality preceding the procedure. Continuous M-mode echocardiogram throughout coronary luminal occlusion, showed a decreased systolic thickening in the septum with a concomitant, prominent notch in early diastole occurring after the seventh beat following occlusion. At the 28th beat, septal systolic motion was absent while only an early diastolic septal motion was observed. Contemporaneously the end-diastolic septal thickness results decreased. Segmental wall motion analysis during ischemia was carried out performing a left ventricular angiogram before, 20 and 50 seconds after the onset of balloon inflation, 5 minutes after completion of the procedure. During the early phase of ischemia, in the ischemic segments, a late systolic lengthening with an early diastolic shortening was observed. We refer to this biphasic motion as the "W" phenomenon which appears to be the early and characteristic change in wall motion and thickness during coronary angioplasty in man.