Τόμος 10 (1992) – Τεύχος 4 – Άρθρο 4 – Επιθεώρηση Κλινικής Φαρμακολογίας και Φαρμακοκινητικής-Ελληνική Έκδοση – Volume 10 (1992) – Issue 4 – Article 4 – Epitheorese Klinikes Farmakologias και Farmakokinetikes-Greek Edition

10: 222-230 (1992)

PHARMAKON-Press: Epitheorese Klin. Farmakol. Farmakokinet.

10: 222-230 (1992)

Ventricular tachyarrhythmias, late potentials

Most patients (pts) who develop sustained ventricular tachycardia (VT) have a history of an extensive myocardial infarction. The anatomic substrate responsible for VT is fixed early after infraction. Factors responsible for trig­gering sustained VT after the substrate was created following the infraction are poorly under­stood. Evidence to date supports a reentrant mechanism as the basis for sustained VT in the setting of coronary artery disease (CAD). Despite major efforts, a specific electrophysiologic sub-state that characterizes the site of origin of VT in man has not yet been identified. So, for the evaluation of ventricular electrical instability, there are currently three approaches: 1) The categori­zation and stratification of spontaneous ventricular arrhythmias 2) The programmed electrical stimu­lation and 3) the direct recording of delayed depolization potential known as Late Potentials (LP). The clinical significance of LP consists of the fact that they frequently represent electrical activity which is generated from arrhythmοgenic substrate responsible for the initiation and per­petuation of life threatening arrhythmias particularly after myocardial infarction. In recent year LP were able to be recorded from the surface of the body with the technique known as Signal Averaging (SAECG). Various studies in the last decade showed that LP were present in 73-92% of the patients who had suffered sustained VT or VF and only 0-6 of the normal persons. The clinical application of SAECG has been used in recent years in pts with syncope, in risk stratification of post myocardial infarction pts and in cases with potentially lethal arrhythmias like, non-sustained VT in a variety of heart disease. There are other possible application which are in the process of investigation. The SAECG can identify a high risk subset of patients following acute myocardial infarction for whom more intensive diagnostic and/or therapeutic measures are indicated. On the other hand the combined use of SAECG with other tests, such as ventricular ejection fraction or Holter monitoring can lead to increased pre­dictive accuracy of the method.

1. Marchlinski, F.E., et al.: Sustained ventricular tachyarrhythmias during the early postinfarction period: Elec­trophysiologic findings and prognosis for survival. J. Am. Coll. Cardiol. 2: 240 (1983).
2. Spielman, S.R., et al.: Chronic recurrent sustained ventricular tachycardia: anatomic, hemodynamic and electrophysiοlogic substrates. In: Ventricular Tachycardias: Mechanism and Management. Edited by M.Ε. Josephson. Mt. Kiaco, N.Y., Futura Publishing, 1982.
3. Roy, D., at al.: Long-term reproducibility and significance of provocable ventricular arrhythmias after myocardial infarction. J. Am. Coll. Cardiol. 5: 1095 (1985).
4. Garan, H, Ruskin, J.N., McGovern, B., and Grant, G.: Serial analysis of electrically induced ventricular arrhythmias in a canine model of myocardial infarction. J. Am, Coll. Cardiol. 5: 1095 (1985).
5. Mason, J.W., et al.: Surgery for ventricular tachycardia: efficacy of left ventricular aneurysm resection compared with operation guided by electrical activation mapping. Circulation 68: 1148, (1982).