Misaki T

On-line assessment of regional ventricular wall motion by transesophageal echocardiography with color kinesis during minimally invasive coronary artery bypass grafting

OBJECTIVE Our objective was to determine the changes in regional ventricular wall motion during minimally invasive direct coronary artery bypass grafting by color kinesis using transesophageal echocardiography. METHODS Minimally invasive coronary artery bypass grafting was performed in 34 patients, during which transesophageal echocardiography was used. Thirteen patients had isolated disease of the left anterior descending artery. Regional ventricular wall motion was analyzed by color kinesis with the SONOS 2500 transesophageal echocardiograph (Hewlett-Packard Co, Andover, Mass). On-line assessment of regional wall motion was continued during the operation. RESULTS Wall motion abnormalities during ischemia were present in 4 cases, left ventricular mid-anterior hypokinesis in 3 cases, and left ventricular apical-lateral hypokinesis in 1 case. In all cases, wall motion was maintained after bypass. In patients with total coronary occlusion, changes in wall motion did not occur during anastomosis. CONCLUSIONS Color kinesis allowed us to evaluate the change in regional ventricular wall motion induced by myocardial ischemia during minimally invasive coronary artery bypass grafting both objectively and quantitatively.

Long-term results of surgery for non-ischemic ventricular tachycardia.

Drug resistant, non-ischemic ventricular tachycardia (VT) was treated in 43 patients by direct surgery based on electrophysiological data. Two main surgical techniques were employed: myocardium was resected followed by cryocoagulation with a special probe in 23 patients with VT originating from the right ventricle. The myocardium was incised followed by cryocoagulation in 10 patients with VT from the left ventricle. The follow-up period ranged from 1 week to 10 years, 4 weeks (mean 3 years, 8 months). After operation, 36 patients (83%) showed complete disappearance of VT without antiarrhythmic therapy. Of these 2 patients died of congestive heart failure not related to VT in the postoperative period at 1 year 4 months, and 2 years 4 months, respectively. In 7 patients, VT remained. In 2, VT disappeared after catheter ablation. In 3 patients, VT became controllable with antiarrhythmic therapy. Operation was not successful in 2 patients (5%); 1 with a giant left ventricular aneurysm died of low cardiac output syndrome due to VT 1 week after operation; the other with arrhythmogenic right ventricular dysplasia originating from both ventricles died suddenly 5 months after operation. The 10-year survival is 89%, and the 10-year freedom from recurrent VT is 83%. These results indicate that surgical management for non-ischemic VT is safe and effective with a high chance of cure.

Ventricular assistance by right free wall dynamic cardiomyoplasty following acute right heart failure in canines

The efficacy of right ventricular assistance provided by electrically conditioned skeletal muscle was studied in 17 canines. The right ventricular free wall was made ischemic and akinetic by ligating all coronary branches supplying it. The latter procedure led to deterioration of hemodynamic parameters. After that, 14 canines were divided into two groups: group 1 (n = 8) was observed without cardiomyoplasty for 2 hours; group 2 (n = 6) underwent right ventricular dynamic cardlomyoplasty with the conditioned left latissimus dorsi. The deterioration in hemodynamic parameters in group 1 showed no further significant change during the period of observation. In group 2, right ventricular function was augmented by cardiomyoplasty, as shown by a significant increase in right ventricular and pulmonary artery pressures. In addition, decreased CVP suggested improved right ventricle (RV) filling. Right ventricular function curves obtained by volume loading In a further group of three canines, group 3, also demonstrated improved right ventricular function. Thus right ventricular dynamic cardiomyoplasty appears to contribute significantly to right ventricular function in a model of acute right heart failure.

Surgical therapy for Wolff-Parkinson-White syndrome in patients with bronchial asthma

The surgical therapy for Wolff-Parkinson-White syndrome in patients with bronchial asthma was studied. Between 1974 and 1992, 447 patients with Wolff-Parkinson-White syndrome were treated, seven of whom had associated severe bronchial asthma. Supraventricular tachyarrhythmias were induced on occasion by bronchodilating agents such as beta-receptor agonists or theophylline preparations. High-dose steroids were required for acute bronchospasm in three patients, despite possibly leading to cardiac dysfunction. Beta-blockers therapy for Wolff-Parkinson-White syndrome can induce bronchospasm; in patients with Wolff-Parkinson-White syndrome and bronchial asthma, pharmacological agents used to treat one condition may exacerbate the other. Therefore, a non-pharmacological therapy was performed, namely surgical division of the accessory conduction pathway via an endocardial approach, in all seven asthmatic patients with Wolff-Parkinson- White syndrome. In all cases, division of the accessory conduction pathway resulted in disappearance of the delta wave, and there were no further tachyarrhythmias either at rest or after administration of bronchodilators. Since surgery, bronchial asthma has been effectively controlled with standard drug therapy in all patients. Non-pharmacological therapy is recommended for patients with Wolff-Parkinson-White syndrome and bronchial asthma.

Evaluation of regional aortic distensibility using color kinesis.

Regional aortic stiffness cannot be evaluated by conventional methods. Regional aortic wall velocity during systole in the descending aorta was evaluated by using transesophageal echocardiography with color kinesis. The authors defined regional aortic distensibility (RAD) by considering pulse pressure, with RAD (μm/s/mm Hg) = (regional aortic wall velocity)/(pulse pressure). RAD was evaluated in 38 patients who had coronary artery disease (CAD) and 10 who did not. RAD decreased depending on aging (partial regression coefficient was -5.39 x 10-1, p < 0.001), and RAD was lower in the CAD group than that in the no-CAD group (p < 0.05). In the CAD group, 19 patients had a single fixed plaque (4 calcified and 15 noncalcified plaques). RAD in the calcified plaque was lower than that in the noncalcified plaque (p<0.01), and RAD was lower in the noncalcified plaque than that in the no-plaque region (p < 0.05). In noncalcified plaques, the relation between RAD and maximum intimal thickness had a signifi cant correlation, r = 0.7, p<0.001. The residual of RAD from the regression line was signifi cantly larger in the calcified plaque than that in the noncalcified plaque (p< 0.001). In conclu sion, RAD can express increasing regional aortic wall stiffness brought about by arteriosclerosis quantitatively. Color kinesis provides information on characteristic difference between calcified and noncalcified plaque.