Power motion imaging can improve image quality in stress conditions with tachycardia

Background: Stress echocardiographic studies are useful, but the evaluation of wall motion is sometimes suboptimal. The recently developed technique of power motion imaging can enhance mobile tissue definition. Hypothesis: The study was undertaken to determine whether power motion imaging improves endocardial definition during tachycardia compared with conventional two-dimensional (2-D) imaging. Methods: Twenty pigs were studied during pacing rates of 100, 120, and 150 beats/min. We compared power motion imaging with standard 2-D imaging using systolic thickening visualization (STV) scores (3 = excellent definition of systolic thickening ∼ 0 = total lack of visualization of systolic thickening) at each heart rate. We calculated the sum of the scores of 22 left ventricular segments as the overall STV score, and also calculated the sum of the scores in 10 parasternal segments and 12 apical segments separately. Results: The overall STV scores in both imaging methods were similar at 100 beats/min, but scores for power motion imaging were significantly higher than those of usual 2-D imaging at 120 and 150 beats/min. Using power motion imaging, the overall STV scores were similar as heart rate was increased; however, while using standard 2-D imaging STV scores were significantly decreased as heart rate was increased. Findings were analyzed separately by parasternal and apical images. Especially in the parasternal images, the scores were significantly increased as heart rate was increased using power motion imaging. Conclusions: We conclude that power motion imaging improves the detection of endocardial border in stress condition with tachycardia, and thus this modality is useful for stress echocardiography.