Localization of Ventricular Tachycardia Exit Site and Subsequent Contraction Sequence and Functional Effects With Bedside Radionuclide Angiography

Objectives In an effort to better understand the clinical effects of ventricular tachycardia (VT), we sought to characterize function and conduction during VT in patients. Background The image evaluation of VT has been limited by the lack of technical tools and its often-dramatic hemodynamic effect. Objective bedside imaging of VT-induced changes in contraction pattern, synchrony, and volumes has never been performed but could aid in the understanding of rhythm tolerance. Methods Equilibrium radionuclide angiography (ERNA) with phase analysis was performed during the course of 32 VT rhythms. Left ventricular ejection fraction, wall motion, synchrony, relative volumes, and exit sites were compared in 13 patients tolerant to VT (Group I) and 9 intolerant to VT (Group II). Results The ERNA VT exit site agreed with the results of electrocardiogram in 26 of 32 (81%) cases and with electrophysiologic study in 16 of 19 (84%) cases (both p < 0.05). A greater rate (157 vs. 130, p < 0.0001) accompanied VT intolerance, but the exit site in 4 patients with multiple VT patterns also appeared important to tolerance. Left ventricular ejection fraction, similar in both groups in sinus rhythm, decreased with VT in Groups I (28 to 19) and II (31 to 15), both p