Total disconnection of the right ventricular free wall: physiological consequences in the dog.

We recently described a new surgical procedure involving total disconnection and subsequent reattachment of the right ventricular free wall ( RVFW ) to confine electrically induced arrhythmic activity to the diffusely diseased RVFW of patients with arrhythmogenic right ventricular (RV) dysplasia. Although no major adverse effects were noted in patients with previously akinetic right ventricles, the consequences of this procedure are unknown in patients with a normally contractile RVFW . This study examined the physiologic consequences of RVFW disconnection in 15 mongrel dogs. Measurements were obtained before surgery, at 30 minutes following surgery, and following a 15-day recovery period. After surgery, the RVFW was electrically isolated from sinus rhythm. At follow-up, left ventricular (LV) pressure, dP/dt, and cardiac output were reduced to 52 mm Hg, 704 mm Hg/sec, and 1.18 L/min, respectively, during sinus rhythm. These values were increased to 76.2 mm Hg, 890 mm Hg/sec, and 1.69 L/min, respectively, when the RVFW was paced in synchrony with sinus rhythm. These studies show that the loss of RVFW contraction depressed hemodynamic function of the normal heart, which is partially compensated by contraction of the left ventricle. Electrical stimulation of the RVFW synchronously with the left ventricle returned cardiac performance toward normal. Finally, this preparation provides a model for independent assessment of the contribution of the RVFW to cardiac function.