TY - JOUR
T1 - R-wave amplitude variations during acute experimental myocardial ischemia
T2 - An inadequate index for changes in intracardiac volume
AU - David, D.
AU - Naito, M.
AU - Chen, C. C.
AU - Michelson, E. L.
AU - Morganroth, J.
AU - Schaffenburg, M.
PY - 1981
Y1 - 1981
N2 - The role of intracardiac volume in controlling electrocardiographic R-wave amplitude changes during acute myocardial ischemia was studied in 24 open-chest dogs. The R-wave amplitude in surface ECG leads 2, V5 and Frank X, Y and Z leads were correlated with hemodynamic, echocardiographic and angiographic changes in 5-minute circumflex coronary artery ligation and reperfusion model. After coronary ligation, left ventricular end-diastolic diameter and volume increased progressively above control, reached a peak and plateau at 120-130 seconds after ligation and did not return to control levels until more than 5 min after release of the occlusion. In contrast, the R-wave amplitude showed a biphasic response to acute ischemia, reaching a nadir (ΣR = 18.2% below control) at 30 seconds after coronary ligation and only subsequently increased to reach a peak (ΣR = 52% above control) at 150 seconds after ligation. In addition, R-wave amplitude returned immediately to control levels within 10 seconds after reperfusion. In six other dogs, both venae cavae were occluded for a 30-second period, beginning 180 seconds after coronary ligation. Although intracardiac volume decreased markedly, R-wave amplitudes increased even more. Thus, the demonstration of discordance between alterations in intracardiac volume and R-wave amplitude in these studies suggests that factors other than intracardiac volume determine R-wave amplitude changes in the course of acute myocardial ischemia.
AB - The role of intracardiac volume in controlling electrocardiographic R-wave amplitude changes during acute myocardial ischemia was studied in 24 open-chest dogs. The R-wave amplitude in surface ECG leads 2, V5 and Frank X, Y and Z leads were correlated with hemodynamic, echocardiographic and angiographic changes in 5-minute circumflex coronary artery ligation and reperfusion model. After coronary ligation, left ventricular end-diastolic diameter and volume increased progressively above control, reached a peak and plateau at 120-130 seconds after ligation and did not return to control levels until more than 5 min after release of the occlusion. In contrast, the R-wave amplitude showed a biphasic response to acute ischemia, reaching a nadir (ΣR = 18.2% below control) at 30 seconds after coronary ligation and only subsequently increased to reach a peak (ΣR = 52% above control) at 150 seconds after ligation. In addition, R-wave amplitude returned immediately to control levels within 10 seconds after reperfusion. In six other dogs, both venae cavae were occluded for a 30-second period, beginning 180 seconds after coronary ligation. Although intracardiac volume decreased markedly, R-wave amplitudes increased even more. Thus, the demonstration of discordance between alterations in intracardiac volume and R-wave amplitude in these studies suggests that factors other than intracardiac volume determine R-wave amplitude changes in the course of acute myocardial ischemia.
UR - http://www.scopus.com/inward/record.url?scp=0019497848&partnerID=8YFLogxK
U2 - 10.1161/01.CIR.63.6.1364
DO - 10.1161/01.CIR.63.6.1364
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AN - SCOPUS:0019497848
VL - 63
SP - 1364
EP - 1371
JO - Unknown Journal
JF - Unknown Journal
IS - 6 I
ER -