Analysis during sinus rhythm of critical sites in reentry circuits of postinfarction ventricular tachycardia.

Background: Critical sites within reentry circuits of postinfarction ventricular tachycardia (VT) were identified during sinus rhythm (SR) and VT to determine whether electrogram characteristics during SR may be helpful in identifying successful ablation sites.

Methods: In 33 patients (mean age 67 +/- 11 yrs) with prior infarction, mapping and radiofrequency (RF) catheter ablation of 57 hemodynamically-tolerated VT's (cycle length 478 +/- 96) were performed. The morphologies of electrograms (EGM) at sites of concealed entrainment (CE) were compared during SR and VT.

Mechanism of ventricular tachycardia termination by pacing at left ventricular sites in patients with coronary artery disease.

Objective: The mechanism by which pacing terminates ventricular tachycardia (VT) may depend on the location of the pacing site relative to the reentry circuit. The purpose of this study was to compare the mechanisms by which pacing terminates VT at left ventricular (LV) sites with and without concealed entrainment (CE) in patients with prior myocardial infarction.

Methods And Results: LV mapping was performed in 29 patients (26 men, 3 women, mean age 67 +/- 11 years, ejection fraction 0.