NON-INVASIVE RECORDING OF LATE VENTRICULAR POTENTIALS - METHODOLOGY AND FIRST CLINICAL-EXPERIENCES

  • 1 January 1981
    • journal article
    • research article
    • Vol. 70  (1) , 1-7
Abstract
Late potentials occurring after the QRS complex were searched for from the body surface using high-gain amplification and signal-averaging techniques with filter settings between 100 and 300 Hz at a sampling rate of 10 kHz. The number of repetitions of the averaging process ranged between 150 and 300; 52 patients were studied. In 11 control subjects, no late potentials were detected within the ST segment. Late potentials were observed in 3/27 patients without previously documented ventricular tachycardia, all having left ventricular aneurysms. All 3 patients had evidence of increased ventricular vulnerability (1 dying from ventricular tachycardia, 1 with stimulus-inducible ventricular tachycardia, 1 with multiple episodes of ventricular fibrillation after surgery). In patients with previously documented ventricular tachycardia and/or fibrillation, late potentials occurred in 7/14 cases (50%), mainly in those with aneurysms (6/8 pts = 75%). Mean onset of late potentials after the QRS complex was 38 .+-. 20.1 ms, mean amplitude was 3.9 .+-. 2.0 uV and mean duration was 17.1 .+-. 5.4 ms. Late potentials, which represent late depolarization of a mass of ventricular tissue after slow conduction, herald increased susceptibility to ventricular tachycardia mainly in patients with ventricular aneurysms.