No abstract

Endocardial catheter mapping was performed in 18 patients with left bundle branch block (LBBB). Four patients had no organic heart disease (group I), six had cardiomyopathy (group LI), and eight had coronary artery disease and previous infarction (group III). Twelve patients had one septal site of left ventricular endocardial breakthrough, while six had two left ventricular endocardial breakthrough sites, with one site always being septal. There was no significant difference among the groups with respect to time of left ventricular breakthrough (group I, 44 msec after the onset of the QRS complex; group II, 58 msec; and group III, 51 msec). Total left ventricular endocardial activation time was significantly longer in group 111 (1 19 msec) than group 1 (81 msec; p < .05) and group 11 (61 msec; p < .001). Duration of total right ventricular endocardial activation was 36 msec (seven patients). The final site of right ventricular activation was at 44 msec after the onset of the QRS complex. We conclude that (1) right ventricular activation occurs before initiation of left ventricular activation in patients with LBBB, (2) left ventricular endocardial activation in patients with LBBB most likely occurs as a result of right-to-left transseptal activation, (3) left ventricular endocardial activation sequence in patients with LBBB is heterogenous, and (4) patients with coronary artery disease and LBBB have significantly longer total left ventricular endocardial activation times than patients with no organic heart disease or those with cardiomyopathies. Circulation 69, No. 5, 914-923, 1984. OUR PRESENT UNDERSTANDING of ventricular activation in man is based on data derived from studies involving preparations in vitro and canine preparations and from intraoperative epicardial mapping of the human heart in a small number of patients. standing of ventricular activation in the human heart with left bundle branch block (LBBB) in vivo is therefore limited by several factors. These include differences between the anatomic and functional properties

Catheter mapping during sinus rhythm was performed in 132 patients with coronary artery disease and 26 patients with congestive noncoronary cardiomyopathy. Each of the patients had a clinical history of one of the following: no ventricular arrhythmia, nonsustained ventricular tachycardia, cardiac arrest, or sustained ventricular tachycardia. The characteristics of the endocardial electrogram and other measured indexes of slow endocardial conduction were compared between patients with different types of disease and in different arrhythmia groups to determine if differences existed. The cardiomyopathic group had a higher percent of normal endocardial electrograms than the coronary artery disease group, with no evidence of slow endocardial conduction. The sustained ventricular tachycardia group exhibited a greater percent of abnormal endocardial electrograms and more evidence of slow endocardial conduction, distinguishing this group from the three other arrhythmia groups. We conclude the following: (1) No. 4, 645452, 1986. LEFT VENTRICULAR mapping in individuals in sinus rhythm has been performed in a variety of patient groups, including those with a normal left ventricle,'-' conduction defects,8-14 coronary artery disease with or without ventricular tachycardia,'2-22 and hypertrophic cardiomyopathy.23 These studies primarily described activation patterns only, although a few attempted to quantitatively and qualitatively characterize local elec-

Previous studies in patients with sustained ventricular tachycardia (VT) have demonstrated the efficacy of surgical and catheter-mediated ablative procedures based on activation mapping during VT. Since extensive preoperative or intraoperative mapping may be impractical due to time constraints or patient intolerance, we sought to define characteristics of the 12-lead electrocardiogram (ECG)

The purpose of this study was to determine left ventricular activation, dispersion of refractoriness, and total recovery time in patients with coronary artery disease and ventricular tachycardia and in patients with the long QT syndrome and to compare these patients with a group of normal patients. Left Patients and Methods Patient PopulationThe study population consisted of 18 patients. The mean age was 46 years with a range from 17 to 72 years. There were 10 men and eight women.