Avtor/Urednik		Zupan, Igor
Naslov		Eksperimentalna kardiologija: električni, mehanični in nevrohumoralni učinki hitrega spodbujanja preddvorov pri raziskovalnem modelu na psih
Tip		članek
Vir		Slov Kardiol
Vol. in št.		Letnik 1, št. 2
Leto izdaje		2004
Obseg		str. 4-14
Jezik		slo
Abstrakt		Introduction. The objectives of the present study were to evaluate the effects of high-rate pacing on sinus node function and intra-atrial conduction; to compare the relationship between mechanical remodeling and atrial electrophysiology and to compare the influence of mechanical remodeling on the increase of plasma renin activity (PRA) and atrial natriuretic peptide secretion (ANP).Methods. Eight dogs were subjected to rapid atrial pacing (AP) at a rate of 400 beats/min for 16 days. After a complete recovery of left ventricular function, they underwent rapid ventricular pacing (VP) of 240 beats/min of equal duration. Sinus node recovery time (SNRT) was obtained in right atrial site at three pacing rates. Atrial effective refractory period (AERP) was measured at cycle lengths 300 and 400 ms, respecively. Left atrial systolic maximal dimension (LAmax) was assessed by echocardiography. Blood samples were taken from the right atrium and from the peripheral vein. Measurements were performed at baseline, immediately after AP or VP, and four weeks after termination of AP or VP.Results. SNRT immediately after AP and VP was significantly prolonged at all three pacing rates (p<0.03). P-wave duration increased significantly after either type of pacing compared with baseline values. AERP at a basic cycle length of 400 ms decreased significantly after either type of pacing compared with baseline values; the difference between tachycardias was significant too (p<0.02). Significant increases (p<0.05) in left atrial dimensions (LA-A) indicated atrial dilatation after either type of pacing, the differences between two groups being insignificant. Atrial reversal pulmonary venous flow (AR velocity) decreased in AP and VP. The difference was highly significant as compared to basal values and also with respect to both tachycardias (p<0.01). In both groups, atrial remodeling occurred in a relatively short period of time. (Abstract truncated at 2000 characters).
Izvleček		Uvod. Namen raziskave je bil preveriti ali obstaja razlika v okvari sinusnega vozla in intraatrijski prevodnosti pri hitri atrijski in hitri prekatni stimulaciji, ugotoviti povezanost mehaničnega remodeliranja atrijev in elektrofizioloških sprememb ter primerjati učinek mehaničnega remodeliranja atrijev na spremembe v plazemski aktivnosti renina (PRA) in na koncentracijo atrijskega natriuretičnega hormona (ANP). Metode. V raziskavo smo vključili 8 psov pasme beagle. Izvajali smo hitro atrijsko stimulacijo (AP) s frekvenco 40o utripov/min v trajanju 16 dni. Po popolni normalizaciji povzročenih elektrofizioloških sprememb in okrevanju funkcije levega prekata smo izvajali hitro prekatno stimulacijo (VP) s frekvenco 240 utripov/min v enakem časovnem obdobju. Pri polovici živali smo raziskavo pričeli z AP, pri drugi polovici pa z VP. Sistolično funkcijo levega atrija smo ocenjevali s pomočjo ehokardiografije. Atrijsko efektivno refraktarno periodo (AERP) smo merili pri intervalih stimulacije 300 in 400 ms, čas okrevanja sinusnega vozla (SNRT) smo izmerili pri treh frekvencah stimulacije. Vensko kri smo odvzeli iz desnega atrija in iz periferne vene. Rezultati. AERP se je pri osnovnem ciklusu stimulacije 40o ms po obeh načinih stimulacije signifikantno skrajšala v primerjavi z bazalnimi vrednostmi, prav tako je bila signifikantna tudi razlika med obema tahikardijama (p<o.o2). SNRT se je podaljšal tako po AP kot po VP. Po obeh načinih stimulacije smo glede na signifikantno povečanje dimenzij (p<o.o5) ugotovili dilatacijo levega atrija v primerjavi z bazalnimi vrednostmi, medtem ko med skupinama ni bilo pomembnih razlik. Velikost vala A v pljučnih venah (retrogradni val AR) se je znižala po AP in VP. Razlika je bila signifikantna tako glede na bazalne vrednosti kot tudi med obema tahikardijama (p<0.01). (Izvleček skrajšan pri 2000 znakih).
Deskriptorji		ATRIAL FIBRILLATION CARDIAC PACING, ARTIFICIAL ATRIAL NATRIURETIC FACTOR RENIN HEART ATRIUM HEART VENTRICLE DISEASE MODELS, ANIMAL DOGS ELECTROCARDIOGRAPHY ELECTRODES, IMPLANTED ECHOCARDIOGRAPHY, TRANSESOPHAGEAL