Session S35.5

QRS Configuration of AIVR Occurring during the Reperfusion Phase of Acute Myocardial Infarction Suggests an Origin from the Reperfused Area

MHAM van Helden*, L Smolders, APM Gorgels

Maastricht University
Maastricht, Netherlands

During the reperfusion phase of acute myocardial infarctions ventricular arrhythmias occur, especially accelerated idioventricular rhythms (AIVR). The characteristics of these AIVR’s are not well known. For this purpose the configurational characteristics of AIVR were studied. It was hypothesized that AIVR’s originate from the reperfused area. Three channel (lead III, V1, V5) 24-hour Holter registrations from patients with acute anterior myocardial infarctions (AAMI) treated with PCI, were analyzed. The site of occlusion was determined by the ST vector in the frontal leads in the 12 lead ECG, classified as proximal (ST vector 0 – minus 180º), mid (0 -30º) and distal (30 - 180º). The total number of different morphologies and configurational characteristics of AIVR, based on QRS width and spatial vector, was assessed. The QRS width was divided in 100-120, 121-140 and >140 ms. Eight sites of origin of the AIVR were defined, based on the polarity in leads III, V1 and V5. Included were 65 patients of whom 28 (43.1%) had a proximal LAD, 15 (23.1%) had a mid LAD and 5 (7.7%) had a distal LAD occlusion. No AIVR was found in 17 patients (26.2%). An average of 3.8 different morphologies per infarct was found in a proximal, 3.0 in a mid and 1.2 in distal LAD occlusion. A QRS width of 100-120 ms was found in 8 (80%) proximal, 2(20%)mid and 0 distal LAD occlusions. In proximal LAD occlusion all 8 configurations occurred, in a mid LAD 7 out of 8 and in a distal LAD 2 out of 8 different morphologies occur. Five out of 6 of the AIVR’s occurring in distal LAD infarcts had a configuration suggesting an antero-apicolateral origin (QRS negative in leads III, V1 and V5). Our results suggest that AIVR’s occurring after recanalization in acute anterior wall infarction originate from the reperfused area: A proximal LAD occlusion provides a larger ischemic area which, during the reperfusion phase, can generate more AIVR, and more different morphologies than more distal LAD occlusions. The finding of more frequent narrow QRS AIVR’s, as seen in proximal and mid LAD reperfusion, is consistent with an origin within the septum, whereas the configuration as seen in distal LAD infarcts fits with an origin from the distal LAD perfusion territory.

(Abstract Control Number: 69)