Avtor/Urednik		Zupan, Igor
Naslov		Vpliv električnih in mehaničnih dejavnikov pri nastanku s tahikardijo povzročene disfunkcije preddvorov
Tip		monografija
Kraj izdaje		Ljubljana
Založnik		Medicinska fakulteta
Leto izdaje		2001
Obseg		str. 69
Jezik		slo
Abstrakt		Introduction. Rapid atrial activation causes alectrical remodeling that promotes the occurrence and the maintenance of atrial fibrillation. Rapid regular atrial pacing produces changes similar to those caused by atrial fibrillation in animal models. The mechanisms of atrial tachycardia-induced remodeling have been extensively explored and involve changes in atrial electrophysiology associated with altered ion channel function. The most important ionic change is reduction in L-type Ca2+ current, which reduces action potential duration and action potential duration adaptation to rate. The aim of this research was to compare the relationship between mechanical remodeling and atrial electrophysiology. Methods. 8 dogs (beagles) were subjected to rapid atrial pacing (AP) at 400 beats/min for 16 days. After complete recovery of electrical variables and left ventricular function evaluated by echocardiography they underwent high rate ventricular pacing (VP) at 240 beats/min for equal duration. In half of them the study was started by AP and in the other half by VP. Left atrial systolic function was assessed by transesophageal echocardiography. Atrial effective refractory period (AERP) was measured at 2 pacing cycle lengths (300 and 400 ms) in one right atrial site and sinus node recovery time (SNRT) was obtained at three pacing rates. Results. AERP at a basic cycle length 400 ms shortened significantly after either type of pacing (AP:115+-17 ms, VP:136 +-22 ms) compared with baseline values (153+-23 ms), the difference between tachycardias was also significant (p<0.02). SNRT was prolonged after both types of pacing, the differences between two groups were not significant. (Abstract trunacted at 2000 characters).
Deskriptorji		TACHYCARDIA ATRIAL FIBRILLATION CARDIAC PACING, ARTIFICIAL ECHOCARDIOGRAPHY, TRANSESOPHAGEAL REFRACTORY PERIOD, NEUROLOGIC DOGS ELECTRIC STIMULATION HEART RATE