Determination of the vectorelectrogram in isolated rat atria : application to the study of arrhythmias
Nivaldo Zafalon, José W. M. Bassani, Rosana A. Bassani
ARTIGO
Inglês
Agradecimentos: We are indebted to Ms Elizângela S Oliveira and Mr Sergio P Moura for the technical support. This study was supported by CNPq (Proc nos 300632/2005-3 and 141175/2002-8)
Abstract: Atrial tachyarrhythmias, the most frequent type of cardiac arrhythmia, are associated with increased stroke risk. Reentry and focal activity are considered as the main mechanisms underlying this dysfunction. In this study, we describe determination of the vectorelectrogram in isolated rat...
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Abstract: Atrial tachyarrhythmias, the most frequent type of cardiac arrhythmia, are associated with increased stroke risk. Reentry and focal activity are considered as the main mechanisms underlying this dysfunction. In this study, we describe determination of the vectorelectrogram in isolated rat atria as a means to distinguish different patterns of electrical propagation. In all studied right atria beating at sinus rhythm, the mean electric vector (MEV) trajectory was clockwise, and each cycle was preceded by electric diastole (null MEV), either in the absence or presence of muscarinic cholinergic or ß-adrenergic receptor stimulation. During cholinergic tachyarrhythmia (induced by high-rate electric stimulation in both atria, plus exposure to carbachol in left atria), vector loops were ellipsoidal and stable, with variable direction, and did not cross the origin, which is consistent with reentrant activation and with findings obtained in vivo by other authors. In contrast, during spontaneous activity induced by rapid pacing in isoproterenol-exposed left atria, vector loops were similar to those in right atria at sinus rhythm, thus suggestive of focal activity. It is concluded that the vectorelectrogram approach allows discrimination of different patterns of propagation during arrhythmia in isolated atria and may be useful for high-output tests of pro- and anti-arrhythmic compounds
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CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ
300632/2005-3 ; 141175/2002-8
Fechado
Determination of the vectorelectrogram in isolated rat atria : application to the study of arrhythmias
Nivaldo Zafalon, José W. M. Bassani, Rosana A. Bassani
Determination of the vectorelectrogram in isolated rat atria : application to the study of arrhythmias
Nivaldo Zafalon, José W. M. Bassani, Rosana A. Bassani
Fontes
Physiological measurement (Fonte avulsa) |