[Influence of wall thickness on asynergy during exercise two-dimensional echocardiography in patients with old...

The relationship between left ventricular wall motion worsening (new asynergy; newly developed or worsened asynergy) in the affected part of old myocardial infarction during exercise two-dimensional echocardiography and the wall thickness at diastole was evaluated in 20 patients with more than 51% diameter stenosis in only the infarcted related artery using symptom-limited graded supine bicycle exercise test and two-dimensional echocardiography. End-diastolic wall thickness at normal part of the wall (WtdN) and infarcted parts (WtdI) on the parasternal short-axis view at the papillary muscle level at rest were measured and the wall thickness ratio, WtdI/WtdN x 100(%), was calculated. The rate pressure product at the time when new asynergy appeared and the appearance time of new asynergy after starting exercise were measured in seconds. Mean values for the 20 patients were wall thickness ratio of 75.7 +/- 10.0% (mean +/- SD), new asynergy appearance time of 219 +/- 116 sec after exercise and rate pressure product of 14,209 +/- 2,997 mmHg. beat/min. Smaller wall thickness ratio was associated with lower rate pressure product levels (r = 0.696, p < 0.01) and shorter appearance time of new asynergy (r = 0.772, p < 0.01). There was no significant correlation between the percentage diameter stenosis of the infarct-related artery and appearance time of new asynergy or rate pressure product. New asynergy appeared at a specific infarcted part of the wall, and thinner walls were associated with shorter appearance time of new asynergy with lower rate pressure product levels, regardless of the severity of stenosis of the infarct-related artery.