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Cardiac Resynchronization Therapy: A Review of Proarrhythmic and Antiarrhythmic Mechanisms
Author(s) -
TURITTO GIOIA,
ELSHERIF NABIL
Publication year - 2007
Publication title -
pacing and clinical electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.686
H-Index - 101
eISSN - 1540-8159
pISSN - 0147-8389
DOI - 10.1111/j.1540-8159.2007.00585.x
Subject(s) - medicine , cardiology , cardiac resynchronization therapy , repolarization , ventricular remodeling , heart failure , sudden cardiac death , population , ejection fraction , electrophysiology , environmental health
Available evidence supports the hypothesis that cardiac resynchronization therapy (CRT) results in favorable structural as well as electrical remodeling. Electrical remodeling seems to be related, to a large extent, to structural remodeling, usually referred to as reverse remodeling of left ventricular (LV) dysfunction. This can lead to amelioration of the arrhythmogenic substrate associated with depressed LV systolic function and heart failure. However, a direct electrophysiological effect due to favorable remodeling of repolarization with reduction of the dispersion of repolarization cannot be ruled out. On the other hand, in a small subgroup of patients, CRT could increase the dispersion of repolarization and induce malignant ventricular tachyarrhythmias. Clinical trials have consistently shown improved outcome with CRT‐defibrillators (CRT‐D) and more trials have demonstrated the benefits of the defibrillator in the population with depressed LV function. However, some physicians argue that implanting the less expensive and less complicated CRT‐pacemaker (CRT‐P) may be appropriate in certain groups of patients. Before this position is accepted, it is imperative that criteria for the selection of this group of patients with presumably low risk for sudden arrhythmic death as well as the proarrhythmic effect of CRT be clearly defined.