Atrial gradient as a potential predictor of atrial fibrillation

Intermittent Atrial Tachycardia Promotes Repolarization Alternans and Conduction Slowing During Rapid Rates, and Increases Susceptibility to Atrial Fibrillation in a Free‐Behaving Sheep Model

“…Weeks of intermittent AT in our model shortened ARI across a wide range of PCLs and blunted its rate adaptation. The “dose‐response” relationship of intermittent AT on remodeling showed that ARI alterations were similar between 3 and 7 weeks of intermittent AT, which agrees with the rapid time course of electrical remodeling from burst pacing …”

“…Several models of atrial fibrillation (AF) have been developed in the last 2 decades based on a phenotype of atrial electrical remodeling by burst pacing or on a phenotype of heart failure induced by rapid ventricular stimulation or slow ventricular rate following atrioventricular block . Atrial burst pacing consistently causes electrical remodeling, although interspecies differences exist in the development of fibrosis .…”

“…Atrial burst pacing consistently causes electrical remodeling, although interspecies differences exist in the development of fibrosis . Atrial burst pacing alters repolarization that includes shortening of effective refractory period (ERP), blunting of ERP rate adaptation and increased dispersion of ERP . Assessment of atrial repolarization, however, has been limited to the measurement of ERP and monophasic action potential recordings, and their rate adaptation …”

Cardiac memory … new insights into molecular mechanisms

“…In addition, the T wave changes of memory can mimic those of ischaemic heart disease (Rosenbaum et al 1982; Katz, 1992; Shvilkin et al 2004) and can impact on and either mask or augment the effects on ECG of anti‐arrhythmic drugs and of other drugs that alter K + channel function (Plotnikov et al 2001). More controversially, and therefore still speculative, cardiac memory may modulate the type of cardiac rhythm expressed, may be arrhythmogenic (although this holds largely for atrium, see Chandra et al 2003, 2005) and may be an early portent of hypertrophy to come (Rosen et al 1998).…”