Haemodynamic (A) and electrocardiographic (B) changes induced by biventricular epicardial and endocardial pacing in six pigs with induced cardiomyopathy. Columns represent mean values. Bars represent SEM. ABF, aortic blood flow; LVP, left ventricular pressure; QRS, QRS complex width; QT, QT interval duration; RVP, right ventricular pressure.