The Effect of Continuous Wave Ultrasonic Therapy on Myocardial Infarction in the Dog
Previous studies have indicated that ultrasonic therapy has some beneficial effects on wound healing specifically with increased vascularity and decreased fibrosis formation. To investigate potential benefits in myocardial healing after ischemic and infarcted events, 24 dogs were studied after coronary artery ligation. Mongrel dogs weighing from 20 to 30 kg. were anesthetized with sodium pentobarbital (30 mg/kg) and a left thoracotomy was performed at the fifth intercostal space. A portion of the fifth rib was removed and the pericardium incised. The heart was suspended by suturing the pericardium to the thoracic wall at five or six points to form a cradle. The pericardium so attached retained the lung from the anterior surface of the heart and thus provided a very good window for the post-operative ultrasonic treatment. The left anterior descending coronary artery or one or two of its anterior branches were ligated depending on the distribution pattern. The dogs were divided into three groups of eight animals each. Group A was studied for four weeks post-operatively, Group B for three weeks and Group C for two weeks. Each group contained four dogs that were treated with the ultrasound and four control dogs that received placebo massage with no ultrasound therapy.