Bradycardia-induced Torsade de Pointes - An arrhythmia Less Understood.
Year: 2010
Type: article
Abstract: Torsade de pointes (TdP) denotes a polymorphic ventricular tachycardia that is associated with prolonged QT interval at baseline, and is potentially life-threatening. Though it is well established that the genesis of TdP is closely linked to the transmural dispersion of repolarisation (TDR), the cellular and electrophysiological milieu predisposing to torsadogenesis in many conditions is not completely understood [1]. Significantly increased TDR at contiguous myocardial sites functions as a re-entrant substrate to initiate and maintain a TdP episode. Increased TDR in myocardium is represented by the electrocardiographic finding of prolonged QT interval. More specifically, the descending limb of the T wave represents TDR and this phase is considered to be a vulnerable period for torsadogenesis [2]. When a premature beat occurs in this period, the arrhythmia is initiated and perpetuated due to phase 2 re-entry or phase 2 early after depolarization. Bradycardia is known to be one of the major factors predisposing to TdP. The inverse relationship between heart rate and repolarization time primarily accounts for bradycardia-induced QT prolongation. In addition, bradycardia increases the torsadogenicity of drugs that block I Kr
Source: PubMed Central
Author: Narayanan Namboodiri
Language: English
Subfield: Cardiology and Cardiovascular Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W2114512476