title: Using devices with a variable postventricular atrial refractory period for cardiac resynchronization.
abstract: Automatic postventricular atrial refractory period (Auto-PVARP) is a dynamic interval designed to provide a longer PVARP at slower rates to enhance protection against pacemaker tachycardia (PMT) and a shorter PVARP to enhance atrial sensing at high rates. Auto-PVARP is often programmed in Medtronic devices for cardiac resynchronization therapy (CRT) with little knowledge of its intricate manifestations and disadvantages. The use of Auto-PVARP is contradictory to the universal teaching that CRT devices should be programmed with a short PVARP. We present the sequential ECGs of a patient with a CRT device programmed with Auto-PVARP in whom the atrial rate was increased with isoproterenol to simulate exercise. The recordings demonstrated that Auto-PVARP produced a substantial delay in the restoration of AV synchrony from the time the spontaneous atrial rate dropped below the programmed upper tracking rate. Auto-PVARP makes little sense (especially in the presence of first-degree AV block) in CRT patients considering that PMT is rare in this situation. In CRT patients, one should program a short and fixed PVARP of ≤ 250 ms.
authors.affiliation: Florida Heart Rhythm Institute, Tampa General Circle, 33606, Tampa, FL, USA. ssbarold@aol.com
authors.forename: S S
authors.initials: SS
authors.lastname: Barold
authors.forename: R X
authors.initials: RX
authors.lastname: Stroobandt
mesh_terms: D000328:Adult; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D004562:Electrocardiography / Q000379:methods*; D006333:Heart Failure / Q000175:diagnosis* / Q000517:prevention & control*; D006801:Humans