Diagnostic Methods Arrhythmia

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) duringVT that could suggest a particular endocardial region of origin and thus facilitate mapping studies. Endocardial mapping was performed during 182 VTs in 108 patients with prior myocardial infarction of either the anterior or inferior wall. Endocardial sites of origin (sites from which > 40 msec of presystolic electrical activity was consistently recorded) were identified with use of catheter (154 VTs) or intraoperative (85 VTs) activation mapping (both methods used in 57 VTs). Twelve-lead ECGs obtained during these VTs were characterized by four features: location of infarction, bundle branch block type configuration, quadrant of QRS axis, and precordial R wave progression pattern. A specific combination of these four features was associated with a particular endocardial region containing the mapped site of origin in 87 VTs (48% of total). An association (> 70% positive predictive accuracy) was more likely to be found in the presence of left, as opposed to right, bundle branch block type patterns (53/73 [73%] vs 34/109 [31%]; p < .001) and in the presence of VT related to inferior, as opposed to anterior, infarction (40/54 [74%] vs 47/128 [37%]; p < .001). An algorithm developed with the above criteria was then applied prospectively to 110 VTs (all mapped) in an additional 63 patients. Each author, blinded to mapping data, used the algorithm to correctly predict endocardial region of origin for a mean of 60 of 65 (93%) VTs to which the algorithm could be applied. These data indicate that the 12-lead ECG during VT can be used to suggest an endocardial region of origin in approximately one-half of VTs in patients with a single site of myocardial infarction. Although this information should not be a substitute for careful mapping when such studies are possible, the findings of this study may be used to facilitate placement of recording electrodes in areas likely to contain sites of origin and thus expedite mapping. Circulation 77, No. 4, 759-766, 1988. IN THE LAST DECADE, a variety of surgical and catheter-mediated means of ablating ventricular tissue have been developed to treat sustained ventricular tachycardia (VT) associated with prior myocardial infarction.1-5 Precise knowledge of the location of areas from which tachycardias arise is imperative to From the Clinical Electrophysiology Laboratory, Hospital of the University of Pennsylvania, Cardiovascular Section, and Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia. Supported in part by grant HL24278 from the National Heart, Lung, and Blood Institute, Bethesda. Address for correspondence: John M. Miller, M.D., Cardiovascular Section, Hospital of the University of Pennsylvania, 3400 Spruce St., Room 654 Ravdin, Philadelphia, PA 19104. Received Sept. 14, 1987; revision accepted Jan. 7, 1988. Dr. Josephson is the Robinette Foundation Professor of Medicine (Cardiovascular Diseases). Vol. 77, No. 4, April 1988 destroy the arrhythmogenic tissue without causing significant damage to more normally functioning ventricular myocardium. Currently, the most reliable method for acquiring information concerning the location(s) of arrhythmogenic areas is activation mapping of the heart during VT6; prior studies have shown that eradication of endocardial tissue from which presystolic electrical activity during VT is recorded can result in cure of VT.3' 7 Detailed activation mapping during VT is not always possible due to hemodynamic intolerance ofVT or changes in QRS morphology of VT.8 Alternative methods for obtaining information regarding "sites of origin" of VT have been applied, including pacemapping9 and noninvasive means of detecting areas of earliest wall motion (gated nuclear scans, echocardiography).1O 13 A previous study from this 759 by gest on A ril 1, 2017 http://ciajournals.org/ D ow nladed from