Recurrent sustained ventricular tachycardia. 2. Endocardial mapping.

Abstract

Endocardial ventricular mapping of 21 ventricular tachyardias (VT) in 17 patients was performed using electrode catheters. Activation at multiple left and right ventricular sites was utilized to determine the site of origin of the VT. Eleven VT had a left bundle branch block pattern (VT-LBBB) and 10 VT had right bundle branch block pattern (VT-RBBB). In all VT-RBBB the earliest site of activation was in the LV or septum. In VT-LBBB the earliest site was RV (4/11), LV (5/11) and septum (2/11). All ventricular tachycardias with QRS less than 140 msec arose in the septum. In patients with an aneurysm, the site of origin of ventricular tachycardia was always in the aneursm. All VT-LBBB arising from the left ventricle originated in an aneurysm involving the septum. QRS changes during ventricular tachycardia were associated with alterations in the patterm of ventricular activation without alteration of the site of origin. In three patients the site of origin predicted by endocardial ventricular mapping was confirmed intraoperatively by epi- and/or endocardial mapping. We conclude that endocardial ventricular mapping demonstrates the limitations of the surface electrocardiogram in localizing the site of origin of ventricular tachycardia. The method may provide important data upon which the surgical therapy of ventricular tachycardia is based.

Characterization of Endocardial Electrophysiological Substrate in Patients With Nonischemic Cardiomyopathy and Monomorphic Ventricular Tachycardia

“…[1][2][3] Results of prior mapping studies indicated that reentrant VT in this setting often originate from the subendocardial surface of infarcted myocardium, adjacent to dense scar or aneurysm. [3][4][5] Nonischemic cardiomyopathy is characterized by myocardial dysfunction in the absence of significant coronary artery disease. In contrast to ischemic heart disease, little is known about the electrophysiological substrate for uniform VT in patients with nonischemic left ventricular (LV) cardiomyopathy.…”

Ventricular Arrhythmias and Myocardial Revascularization

“…Early surgical treatments were performed in cases of major scars, so called ventricular aneurysms, which were resected (2,3) and within the same procedure, deep encircling incisions of different extent should isolate the electrically instable boarder zone from the remaining ventricle (4,5). With the introduction of electrophysiological investigations, the origin of such reentry circuits along the border zone was localized and an endocardial resection of this focus performed (6,7,8,9,10,11). However recurrent Vt´s were observed frequently after these procedures, oftentimes different from the primary clinical and also electrophysiological presentation.…”

Relation Between Body Surface Mapping and Endocardial Spread of Ventricular Activation in Postinfarction Heart

“…The endocardial VT exit site was de ned as the site where the earliest endocardial breakthrough occurred relative to the onset of the QRS complex on the simultaneously recorded surface ECG. 19 An epicardial breakthrough was de ned as the absence of endocardial activity before or within 10 msec after the onset of the body surface QRS complex. If activation times of signals recorded at contiguous sites (7 to 9 mm apart) differed by 50 msec, conduction block was considered present.…”