The atrial activation sequences during 15 episodes of sustained atrial flutters were determined in the isolated hearts of four dogs with surgically induced right atrial enlargement (TI/PS dogs). These sequences were compared with the activation sequences of six episodes of nonsustained atrial tachyarrhythmias induced in three control hearts. Total endocardial activation of both atria during nor...

• The existence of brouchopulmonary anastomoses has led to the general belief that the blood from the aorta and bronchial arteries can reach the pulmonary vessels and left atrium. There is reasonable evidence to suggest that the reverse can occur. Three observations pertain to the flow of blood from the pulmonary artery to the bronchial veins and right atrium: (a) In 1931 Berry and Daly perfuse...

•Almost all previous attempts to study the bronchial circulation have been limited to measurements of blood flow in the bronchial arteries and bronchopulmonary anastomoses. There have been two studies devoted to estimations of blood flow in the bronchial veins of the normal dog. In 1931, Berry and Daly perfused in dogs either the posterior bronchial artery of one lung or the entire aortic segme...

We evaluated the effects of slow-rate atrial pacing on impulse formation of the sinus node in 13 isolated rabbit right atria using the microelectrode technique. After the spread of activation was mapped to determine true sinoatrial conduction time (SACT) (38 ± 16 msec [± SD]), the atrium was paced for eight beats at constant intervals slightly shorter than spontaneous cycle length in steps of 1...

Detailed electrophysiologic evaluation of the sinus node and atrium was undertaken in 26 patients. Half had bior trifascicular conduction disease (BTD) and the others had a narrow QRS (non-BTD). BTD and non-BTD groups were comparable with respect to age, sex and incidence of coronary artery disease (CAD). One or more electrophysiologic abnormalities of the sinus node or atrium were found in nin...

Ventricular inward rectifier K(+) current (I(K1)) is substantially larger than atrial, producing functionally important action potential differences. To evaluate possible molecular mechanisms, we recorded I(K1) with patch-clamp techniques and studied Kir2.1 and Kir2.3 subunit expression. I(K1) density was >10-fold larger in the canine ventricle than atrium. Kir2.1 protein expression (Western bl...

Atrial fibrillation (AF) may result from stationary reentry in the left atrium (LA), with fibrillatory conduction toward the right atrium (RA). We hypothesize that periodic input to the RA at an exceedingly high frequency results in disorganized wave propagation, compatible with fibrillatory conduction. Simultaneous endocardial and epicardial optical mapping (di-4-ANEPPS) was performed in isola...