Frequency and Significance of Left and Right Ventricular Late Potentials after Myocardial Infarction in Man

Left and right heart catheterization was conducted on 45 patients with a history of myocardial infarction in order to detect so-called ventricular late potentials by means of endocardiac mapping. The endocardiac signals were amplified 100 to 10,000 times at a low noise level using bipolar electrode catheters. The signals were stored unfiltered and visualized directly on an oscilloscope. Consistently recurring late potentials were recorded after QRS complexes in 32 patients (71%). They ranged in amplitude from 50 to 780 microV, while the coupling intervals were measured in the range of 80 to 620 ms from the beginning of the QRS complex to the beginning of the late potential. In some patients, the intracardially registered and/or Holter-monitored ventricular ectopic beats occurred with a delay, corresponding to the delayed occurrence of the ventricular late potentials.