Changes in Left Ventricular Hemodynamics of Hypertrophic Obstructive Cardiomyopathy (HOCM) Patients Treated with VAT Sequential Pacing

The functional behavior of the left ventricular (LV) outflow obstruction, and its accessibility by artificial pacing in patients suffering from hypertrophic obstructive cardiomyopathy (HOCM) is known from the literature [1, 3, 7, 8]. The basic principle of this attempt, described by Hassenstein et al. [2] and by Johnson and Daily [3] in 1975, is to stimulate the LV in a P-wave-triggered (VAT) mode, but with a much shorter conduction time than the patient’s atrioventricular (AV) conduction. Thus, foreign excitation of the ventricles from the right ventricular apex delays the contraction of the obstructive segment of the septum and diminishes the pressure gradient of the outflow tract.