[Correlation between parameters measured by high amplification ECG and results of programmed ventricular stimulation after myocardial infarct]

The presence of late ventricular potentials and the induction of sustained ventricular tachycardia (SVT) by programmed ventricular stimulation (PVS) after myocardial infarction are markers of the risk of serious ventricular arrhythmias. The authors studied the value of signal averaged electrocardiography (SAECG) compared with induction of SVT by PVS in 118 consecutive patients 4 to 8 weeks after myocardial infarction. In addition to this study population, a control group of 22 patients with spontaneous SVT after myocardial infarction was also considered. Three parameters were measured after averaging 200 QRS complexes: the duration of the filtered QRS complex (QRSd), the duration of signals not exceeding 40 microV (LAS) and the root mean square of the voltage of the last 40 milliseconds (RMS). Abnormal values were defined as: QRSdor = 120 ms, LASor = 39 ms, RMSor = 20 microV. Patients in the study population were subdivided into 3 groups: Group I (n = 17) inducible SVT; Group II (n = 72) no inducible arrhythmias; Group III (n = 29) induction of sustained ventricular flutter or primary ventricular fibrillation requiring immediate cardioversion. The results showed a good correlation between SAECG and induction of SVT. The sensitivity (Se), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV) were as follows: 1) QRSd120 ms: Se = 82%, Sp = 80%, PPV = 41%, NPV = 96%; 2) LAS39 ms: Se = 59%, Sp = 85%, PPV = 38%, NPV = 92%; 3) RMS20 V: Se = 59%, Sp = 88%, PPV = 43%, NPV = 93%.(ABSTRACT TRUNCATED AT 250 WORDS)