Using devices with a variable postventricular atrial refractory period for cardiac resynchronization.
Summary of "Using devices with a variable postventricular atrial refractory period for cardiac resynchronization."
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.
-, Florida Heart Rhythm Institute, Tampa General Circle, 33606, Tampa, FL, U.S.A., firstname.lastname@example.org.
This article was published in the following journal.
Name: Herzschrittmachertherapie & Elektrophysiologie
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/22349662
- DOI: http://dx.doi.org/10.1007/s00399-012-0167-0
Medical and Biotech [MESH] Definitions
Refractory Period, Electrophysiological
The period of time following the triggering of an ACTION POTENTIAL when the CELL MEMBRANE has changed to an unexcitable state and is gradually restored to the resting (excitable) state. During the absolute refractory period no other stimulus can trigger a response. This is followed by the relative refractory period during which the cell gradually becomes more excitable and the stronger impulse that is required to illicit a response gradually lessens to that required during the resting state.
Rapid, irregular atrial contractions caused by a block of electrical impulse conduction in the right atrium and a reentrant wave front traveling up the inter-atrial septum and down the right atrial free wall or vice versa. Unlike ATRIAL FIBRILLATION which is caused by abnormal impulse generation, typical atrial flutter is caused by abnormal impulse conduction. As in atrial fibrillation, patients with atrial flutter cannot effectively pump blood into the lower chambers of the heart (HEART VENTRICLES).
Refractory Period, Psychological
A delayed response interval occurring when two stimuli are presented in close succession.
N-Butyl-N-(2-(diethylamino)ethyl)-1-naphthamide. A proposed antiarrhythmic that prolongs myocardial refractory period and stabilizes cell membranes.
Computer Storage Devices
Devices capable of receiving data, retaining data for an indefinite or finite period of time, and supplying data upon demand.
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