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Asymmetric distribution of left ventricular asynergy in coronary artery disease and its relation to coronary stenoses
Insights
Coronary artery disease causes asymmetric left ventricular wall motion abnormalities. This study links this pattern to the coronary artery
Area of Science:
- Cardiology
- Cardiovascular Imaging
- Cardiac Physiology
Background:
- Coronary artery disease (CAD) frequently leads to impaired left ventricular (LV) function.
- Asynergy, or abnormal wall motion, in the LV can be a marker of myocardial ischemia.
- Understanding the distribution of LV asynergy is crucial for assessing disease severity and prognosis.
Purpose of the Study:
- To investigate the prevalence and severity of asynergy across different left ventricular segments in patients with CAD.
- To determine if the distribution of asynergy is uniform or asymmetric.
- To explore potential explanations for any observed asymmetric patterns of LV asynergy.
Main Methods:
- Evaluated 100 patients with coronary artery disease (CAD).
- Assessed asynergy in 9 left ventricular (LV) segments using radionuclide and contrast angiography.
- Correlated asynergy patterns with coronary artery anatomy, including occlusions and stenoses.
Main Results:
- Asynergy was significantly more prevalent and severe in medial segments compared to basal segments for anterior, septal, and lateral LV walls.
- The inferior LV wall showed equally severe asynergy in both medial and basal segments.
- Asynergy distribution did not correlate with uniform distribution of coronary artery stenoses, suggesting a vascular supply pattern influence.
Conclusions:
- The asymmetric distribution of LV asynergy in CAD patients is likely due to the asymmetric nature of the coronary arterial supply tree.
- Vascular distance from coronary ostia appears to be a key factor in the prevalence of asynergy in specific LV segments.
- The longer, more tortuous path of the right or dominant circumflex artery to the basal inferior wall increases its vulnerability to proximal stenoses and pressure attenuation.
Abstract:
In 100 patients with coronary artery disease (CAD), the prevalence and severity of asynergy was determined for 9 left ventricular (LV) segments by both radionuclide and contrast angiography. The anterior, septal and lateral LV walls had significantly more prevalent and more severe asynergy in the medial segments than in the basal segments. In contrast, the inferior LV wall exhibited equally severe asynergy in both the medial and basal segments. In general, asynergy was most severe in the apical, medial septal, medial inferior and basal inferior LV segments. This asymmetric distribution of LV asynergy could not be explained by the distribution of occlusions or significant stenoses in the arterial tree, which were relatively uniformly distributed among the left anterior descending (32%), left circumflex (29%) and right (26%) coronary arteries. It is postulated instead that the asymmetric distribution of LV asynergy results from asymmetry of the coronary arterial tree supplying the left ventricle and that the prevalence of asynergy in an LV segment is directly related to its vascular distance from the coronary ostia. Unlike the relatively direct supply of the left anterior descending and circumflex arteries to the basal segments of the anterior, septal and lateral LV walls, the arterial supply to the basal inferior wall begins only after the right or dominant circumflex artery has traversed the length of the atrioventricular groove, significantly increasing its susceptibility to the pressure attenuation and occlusive jeopardy of more proximal stenoses.