A multi-modal electrotherapy apparatus including circuitry for administering defibrillation therapy and for administering medium voltage therapy (MVT) adapted to reduce the side effects of MVT. The electrotherapy apparatus is configured to selectively deliver MVT to vectors not involving the ventricles and defibrillation therapy to vectors involving the ventricles. The apparatus can use biphasic waveforms configured to avoid capture of cardiac cells during MVT. The electrotherapy apparatus can minimize the risk of applying MVT at inappropriate times, such as during atrial fibrillation or where conventional ventricular tachycardia or ventricular fibrillation therapy is more appropriate.
