13th International Congress
THE "NEW FRONTIERS"
OF ARRHYTHMIAS 1998

January 24-31, 1998
Marilleva, Trento, Italy

RT-46

Ventricular repolarization abnormalities during and after paroxysmal supraventricular tachycardia

Nelly Paparella, Giuseppe Fuca, Riccardo Cappato*, Feifan Ouyang*, Paolo Alboni.
Division of Cardiology, Ospedale Civile, Cento, Italy,
* II Med ABT - AK St. George, Hamburg, Germany

Methods

We prospectively investigated 102 patients with spontaneous reentrant supraventricular tachycardia. The inclusion criteria were the following: 1) paroxysmal supraventricular tachycardia with narrow QRS complex related to AV nodal or AV reentry; 2) hospital stay for at least 12 hours; 3) documentation of a previous standard ECG performed during sinus rhythm. We excluded 1) patients with concomitant affections known to modify ventricular repolarization (known ischemic heart disease, electrolyte abnormalities, etc); 2) patients taking digitalis or psychotrophic drugs; 3) patients with persistent or intermittent bundle branch block; 4) patients with Wolff Parkinson White syndrome. During tachycardia the type of reentry was defined on the base of common used criteria^4,5. We analyzed the cycle lenght, the amount and the localization of ST segment depression when > 1 mm and the tachycardia duration. We enrolled 102 patients; the age was 52 ± 18 yrs (range 8-84), 68 were female; 87 patients had no history or clinical evidence of heart disease and 15 showed organic heart disease. The supraventricular tachycardia involved an AV nodal reentry in 74 patients and a concealed AV by-pass tract in 28. The tachycardia duration was 136 ± 190 minutes (range 1 min-16 hours), and the heart rate was 176 ± 28 bpm (range 100-300 bpm).

A ST segment depression > 1 mm in one or more leads was present in 67 patients (66%); the mean maximum ST segment depression was 2 ± 1 mm (range 1-7 mm). With regard to ventricular repolarization localization in these 67 patients, the ST segment was depressed in one or more of the inferior leads (II, III, aVF) in 47 patients (70%), in the later leads (I, aVL, V₅,V₆) in 48 patients (72%), in one or more of the anteroseptal leads (V₁,-V₄) in 55 patients (82%).

Comparing the patients with ST segment depression with those without this abnormality, no statistically significant differences were present between the two groups with regard to age, sex, distribution, presence of organic heart disease, type of reentrant tachycardia, heart rate or duration of the arrhythmias (Tab. I). The correlation between the ST segment depression and age, tachycardia rate and tachycardia duration was investigate. The only significant correlation, even if slight was observed between the ST segment depression and the tachycardia rate (r = +0.26, p = 0.03).

Among the patients with ST segment depression, comparing patients with organic hear disease with those without heart disease, the former were older (65 ± 16 vs 50 ± 18 yrs, p = 0.002) and showed a more marked ST segment depression (2.6 ± 1 vs 2 ± 1 mm, p = 0.02) (Tab. II).

TABLE I - Comparison of clinical and electrocardiographic variables between patients without and with ST segment depression (> 1 mm) during tachycardia

T = tachycardia.

TABLE II - Comparison of clinical and electrocardiographic variables in the patients with ST depression during tachycardia, with and without heart disease