[Hemodynamic significance of atrio-ventricular sequence in the example of an observed case]

A case of a 62 year old man with chronic complete atrio-ventricular block but persistent electrical and mechanical atrial activity is presented. The patient was treated by ventricular pacing of the VVI type. During cardiac catheterization right atrium, right ventricle and pulmonary pressure were recorded at basal conditions; right ventricle contractility index and cardiac output were also estimated. An elevation of right atrial pressure simultaneously with a fall of right ventricle and pulmonary pressure were repeatedly observed. These changes were a consequence of atrio-ventricular sequence disorders resulting in un-coordination of atrial and ventricular contractions. Hemodynamic parameters were restored to the physiological range only during the chance appearance of normal atrio-ventricular sequence. The presented observations support the known fact that ventricular pacing in patients with complete atrio-ventricular block may lead to serious hemodynamic disturbances.