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Titolo:
EFFECT OF SUSTAINED LOAD ON DISPERSION OF VENTRICULAR REPOLARIZATION AND CONDUCTION TIME IN THE ISOLATED INTACT RABBIT HEART
Autore:
ZABEL M; PORTNOY S; 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,DIV CLIN PHARMACOL WASHINGTON DC 00000 GEORGETOWN UNIV,DIV CARDIOL WASHINGTON DC 00000
Titolo Testata:
Journal of cardiovascular electrophysiology
fascicolo: 1, volume: 7, anno: 1996,
pagine: 9 - 16
SICI:
1045-3873(1996)7:1<9:EOSLOD>2.0.ZU;2-Z
Fonte:
ISI
Lingua:
ENG
Soggetto:
ACTION-POTENTIAL DURATION; SUDDEN CARDIAC DEATH; MECHANOELECTRICAL FEEDBACK; CANINE HEARTS; CATHETER TECHNIQUE; QT-DISPERSION; VOLUME LOAD; PIG-HEART; ARRHYTHMIAS; REFRACTORINESS;
Keywords:
MONOPHASIC ACTION POTENTIALS; MECHANICAL LOAD; EXPERIMENTAL STUDIES; ELECTROPHYSIOLOGY;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
43
Recensione:
Indirizzi per estratti:
Citazione:
M. Zabel et al., "EFFECT OF SUSTAINED LOAD ON DISPERSION OF VENTRICULAR REPOLARIZATION AND CONDUCTION TIME IN THE ISOLATED INTACT RABBIT HEART", Journal of cardiovascular electrophysiology, 7(1), 1996, pp. 9-16

Abstract

Introduction: It is well known that myocardial stretch can elicit ventricular arrhythmias in experimental models. However, previous reportshave predominantly documented stretch-induced arrhythmias during short, pulsatile stretch. The arrhythmogenic mechanism of sustained staticstretch is incompletely understood. Methods and Results: To examine the influence of sustained load on several electrophysiologic parameters, a latex balloon was placed into the left ventricle of ten isolated Langendorff-perfused rabbit hearts and filled with a neutral volume offluid. The heart was paced from a catheter inside the right ventricle(apicoseptal endocardial position), and the following parameters werestudied during steady-state pacing with a cycle length of 500 msec (S1) and during extrastimulation (S2, base drive of 8 beats): monophasicaction potential (MAP) durations at 90% repolarization (APD(90)) from5 to 6 epicardial electrodes located on both ventricles and one rightventricular endocardial contact electrode; dispersion of APD(90) (range of MAP durations from all electrodes); effective refractory period (ERP) and longest activation time (pacing stimulus to MAP upstroke). After baseline recordings, the balloon inside the left ventricle was filled with a volume of 1.0 mt of fluid by means of a servo-controlled pump. The ERP was significantly shortened from 198 +/- 9 msec at baseline to 183 +/- 8 msec during sustained load (P < 0.03). Similarly, the average APD(90) was shortened from 180 +/- 5 msec at baseline to 175 +/- 6 msec during sustained load (P < 0.006) with steady-state pacing and from 178 +/- 6 msec to 170 +/- 8 msec during premature extrastimulation (P < 0.03). At the same time, dispersion of APD(90) was increasedfrom 27 +/- 5 msec to 38 +/- 6 msec (P < 0.002) during steady-state pacing and from 28 +/- 4 msec to 38 +/- 6 msec (P = 0.013) during premature extrastimulation. The longest activation time among all MAP recordings was increased from 39 +/- 2 msec to 43 +/- 3 msec (P = 0.003) during steady-state pacing and from 56 +/- 6 msec to 69 +/- 6 msec during premature extrastimulation (P < 0.003). Conclusions: Sustained load shortens the ERP and the mean APD(90), and at the same time increases dispersion of APD(90) and prolongs activation times, These findings provide additional insight into the arrhythmogenic mechanisms of sustained mechanical load.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 24/11/20 alle ore 10:41:51