A nonsurgical canine model of chronic left ventricular myocardial dysfunction

A simple technique of producing left ventricular myocardial damage accompanied by chronic complete heart block in dogs is described. The method is accomplished by repetitive transmyocardial DC shock with a guide wire introduced percutaneously and positioned in the left ventricle along the intraventricular septum and an external paddle at the left ventricular apex. Twelve weeks after the procedure significant hemodynamic changes included a fall in heart rate from a control of 76 +/- 19 (SD) to 43 +/- 9 beats/min (P less than 0.001), a rise in left ventricular filling pressure from 9 +/- 4 to 28 +/- 10 mmHg (P less than 0.001), and a fall in cardiac output from 3.1 +/- 1 to 2.3 +/- 0.6 l/min (P less than 0.05). Weekly echocardiography revealed a progressive increase in left ventricular end-diastolic diameter from 3.56 +/- 0.72 to 4.84 +/- 0.47 cm (P less than 0.01). Survival rate was 70%. Therefore, this relatively noninvasive technique is an effective means of producing chronic left ventricular myocardial dysfunction in the dog.