OBJECTIVES

Recently the plication of the left ventricular free wall (PLVFW) was described in healthy dogs, reducing the left ventricular cavity. Based on La Place's law this reduction could decrease the tension on the left ventricular wall and improve the ventricular contractility.

The goal of this study was to evaluate the safety and efficacy of this technique in dogs with doxorubicin-induced cardiomyopathy and normal ones in a period of six months.

MATERIALS

Five normal mongrel dogs (control group) and three dogs with cardiomyopathy induced by doxorubicin were submitted to PLVFW. After induction with propofol (10 mg/kg) and administration of sevoflurane (3,5 V%)in a oxygen mixture, in a semi-closed circuit system, left thoracotomy on the 6th space, pericardiotomy and PLVPW were performed. The dogs were evaluated 1 day before and 1,2,7,15,21,30,60,90,120,150 and 180 days after the surgery by physical examination, measurement of arterial blood pressure, electrocardiography(ECG), echocardiography, blood count and serum chemistry. Continuous ECG (Holter) was performed for 24 hrs after surgery and cardiac output were measured by thermodilution immediately before and after the plication. Statistical analyses was achieved by analysis of variance, and means were compared by Tukey's test (a value of p<0.05 was considered significant)

RESULTS

The ECG showed sinus rhythm with ventricular prematures complexes and short periods of ventricular tachycardia, until 48h after surgery in both groups. The same findings were seen in Holter ECG. In control group the mean of cardiac output (CO) was 2.038 L/min before the surgery and 2.23 L/min after it. In doxorubicin group CO came from 1.61 L/min (before surgery) to 2.21 L/min after surgery. Arterial blood pressure maintained stable along the study in both groups. Ventricular area and volume decreased after surgery in both groups. In doxorubicin group, the mean of fractional shortening (FS) was 17% before surgery, being increased to 24% 2 days after and 36,66% at six months follow-up(p<0.05) demonstrating an improvement of left ventricular function.

CONCLUSION

In this study, the plication of the left ventricular free wall caused an improvement of the left ventricular function in dogs with cardiomyopathy induced by doxorubicin. The left ventricular function was even better at six months after surgery.

Based on this result, the authors consider this procedure as an alternative for treatment of dogs with dilated cardiomyopathy.