Smith, Ralph E.

Simultaneously recorded standard electrocardiograms (ECG) and Frank vectorcardiograms (VCG) were correlated with the coronary arteriograms and the left ventriculograms of 210 patients. Quantitative criteria were applied to ECG measurements made by manual technics and to VCG measurements obtained by computer technics. As the extent of significant arteriographic disease increased, the frequency of ECG and VCG evidence of "definite" myocardial infarction (MI) increased. The VCG was diagnostic of MI in a greater number of patients than the ECG (50 versus 39, P < 0.01) and excelled in the detection of multiple areas of infarction in a greater number of patients (13 versus six, P < 0.05). This increased sensitivity was gained in anterior, inferior, and true posterior infarcts. Excluding patients with myocardiopathy, all MIs diagnosed from the VCG and all but one from the ECG were associated with significant arteriographic disease in the distribution of the predicted nutrient artery. Quantitative VCG analysis appears superior to the usual ECG analysis in the accurate detection of MI. When MI is diagnosed by either technic, significant associated coronary artery disease can be anticipated in a predictable anatomic distribution.

Ten patients with the electrocardiographic diagnosis of atrial flutter were investigated by exploration with electrodes within the esophagus and the right atrium. The records obtained were studied in regard to the timing of the intrinsic deflection and the contour of the atrial waves, as recorded at various sites. In four patients, atrial activation progressed in sequence cephalad in the left atrial wall and caudad in the right atrium. This process continued through two thirds of the total atrial cycle, favoring "circus movement" as the underlying mechanism. In six other patients, activation was believed to originate low in the left atrium, with simultaneous spread of excitation of both atrial walls in a general cephalad direction and terminating within the first half (usually the first third) of the atrial cycle. This pattern is compatible with, but not conclusive of, an ectopic focal mechanism. Serial records in one patient are presented in which transformation of one type into a second type of atrial flutter is suggested. It is likely that at least two mechanisms are present in human atrial flutter.