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Titolo:
IS DISPERSION OF VENTRICULAR REPOLARIZATION RATE-DEPENDENT
Autore:
ZABEL M; WOOSLEY RL; FRANZ MR;
Indirizzi:
VET ADM MED CTR,DIV CARDIOL,50 IRVING ST NW WASHINGTON DC 20422 VET ADM MED CTR,DIV CARDIOL WASHINGTON DC 20422 GEORGETOWN UNIV WASHINGTON DC 00000
Titolo Testata:
PACE-PACING AND CLINICAL ELECTROPHYSIOLOGY
fascicolo: 10, volume: 20, anno: 1997,
parte:, 1
pagine: 2405 - 2411
SICI:
0147-8389(1997)20:10<2405:IDOVRR>2.0.ZU;2-K
Fonte:
ISI
Lingua:
ENG
Soggetto:
ACTION-POTENTIAL DURATION; LONG QT SYNDROME; HEART-RATE; MYOCARDIAL-INFARCTION; CYCLE LENGTH; INTERVAL; RECOVERY; SOTALOL; ELECTROCARDIOGRAMS; ARRHYTHMIAS;
Keywords:
DISPERSION OF REPOLARIZATION; RATE DEPENDENCE; QT DISPERSION;
Tipo documento:
Article
Natura:
Periodico
Citazioni:
28
Recensione:
Indirizzi per estratti:
Citazione:
M. Zabel et al., "IS DISPERSION OF VENTRICULAR REPOLARIZATION RATE-DEPENDENT", PACE, 20(10), 1997, pp. 2405-2411

Abstract

QT dispersion has been adopted as a new index for the noninvasive assessment of the inhomogeneity of repolarization and has been evaluated in several clinical studies as an index of arrhythmia propensity. in most of these studies, indices of dispersion of repolarization were rate corrected by the Bazett formula calculating QT dispersion as QT(c)max-QT(c)min or JT dispersion as JT(c)max-JT(c)min, implying that dispersion of repolarization also changes with heart rate. This study aimed to determine in the electrically paced isolated heart whether dispersion of ventricular repolarization is rate dependent. Multiple (5-7) monophasic action potentials (MAPs) were recorded simultaneously from theepicardium and endocardium of both Ventricles in 18 isolated Langendorff-perfused rabbit hearts. Hearts were paced from a right ventricularsite at basic cycle lengths (CL) between 1,200 and 300 ms in 100-ms decrements. Action potential duration was measured at 90% repolarization (APD(90)), and recovery time (RT) was defined as the sum of APD(90) and activation time in each of the simultaneous MAP recordings. The dispersion of APD(90) and RT, respectively, were calculated as the maximal difference among all recordings. APD(90) and RT shortened continuously throughout the range of paced steady-state CLs from 1,200 to 300 ms. APD(90) was 197.6 +/- 6.1 ms at a CL of 1,200 ms and decreased to 148.5 +/- 2.5 ms at a CL of 300 ms (P < 0.0001). RT was 228.2 +/- 6.2 ms at a CL of 1,000 ms and decreased to 175.9 +/- 2.9 at a CL of 300 ms(P < 0.0001). In contrast, dispersion of APD(90) and RT did not change significantly. Dispersion of APD(90) was 24.8 +/- 2.3 ms at a CL of 1,200 ms, 26.1 +/- 1.9 msec at a CL of 1,000 ms, and 21.6 +/- 2.1 at aCL of 300 ms (NS). Dispersion of RT was 29.7 +/- 3.4 ms at a CL of 1,200 ms, 29.0 +/- 3.0 ms at a CL of 1,000 ms, and 32.7 +/- 3.2 ms at a CL of 300 ms (NS). in contrast to the duration of the QT interval, dispersion of ventricular repolarization does not change significantly with pacing induced changes in CL. Assuming that the rate-dependent behavior of action potential duration is similar between the rabbit and human heart, a rate correction of parameters of dispersion of repolarization is probably unnecessary.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 30/03/20 alle ore 12:49:44