title: Time course of structural adaptations in chronic AV block dogs: evidence for differential ventricular remodeling.
abstract: To determine the nature and time course of biventricular hypertrophy and concomitant electrical and mechanical changes after creation of complete atrioventricular block (CAVB), six adult dogs (22-30 kg) were subjected to serial magnetic resonance imaging (MRI) and electrocardiography. After 6 days of CAVB, left ventricular (LV) mass, ejection fraction (EF), and Q-T time at a paced rhythm of 60 beats/min were already significantly increased. Maximal values were reached within 14-21 days of CAVB: LV mass, from 116 +/- 11 to 143 +/- 12 g; right ventricular (RV) mass, from 40 +/- 3 to 55 +/- 6 g; EF, from 68 +/- 6% to 86 +/- 5%; and Q-T time, from 285 +/- 25 to 330 +/- 35 ms, all P < 0.05. Cardiac output returned to baseline at day 14. End-diastolic wall thickness increased only in the RV, in which angiotensin type 1 (AT1) receptor mRNA expression was significantly greater. The autopsy correlated well with the MRI results (r = 0.98, P< or = 0.01). In conclusion, electrophysiological, mechanical, and structural adaptation processes after bradycardia-induced volume overload develop rapidly and are completed within 3 wk. The degree of hypertrophy was greater in the RV, which was associated with an increase in AT1 receptor mRNA.
authors.affiliation: Department of Cardiology, Academic Hospital Maastricht, Cardiovascular Research Institute Maastricht, 6202 AZ Maastricht, The Netherlands.
authors.forename: S C
authors.initials: SC
authors.lastname: Verduyn
authors.forename: C
authors.initials: C
authors.lastname: Ramakers
authors.forename: G
authors.initials: G
authors.lastname: Snoep
authors.forename: J D
authors.initials: JD
authors.lastname: Leunissen
authors.forename: H J
authors.initials: HJ
authors.lastname: Wellens
authors.forename: M A
authors.initials: MA
authors.lastname: Vos
mesh_terms: D000818:Animals; D001835:Body Weight; D002302:Cardiac Output; D002908:Chronic Disease; D004195:Disease Models, Animal; D018450:Disease Progression; D004285:Dogs; D004562:Electrocardiography; D005260:Female; D006327:Heart Block / Q000150:complications / Q000473:pathology* / Q000503:physiopathology; D006352:Heart Ventricles / Q000378:metabolism / Q000473:pathology; D017379:Hypertrophy, Left Ventricular / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology; D017380:Hypertrophy, Right Ventricular / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology; D008279:Magnetic Resonance Imaging; D008297:Male; D009206:Myocardium / Q000378:metabolism / Q000473:pathology; D009929:Organ Size; D012333:RNA, Messenger / Q000378:metabolism; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D011945:Receptors, Angiotensin / Q000235:genetics / Q000378:metabolism; D015203:Reproducibility of Results; D013318:Stroke Volume; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis / Q000503:physiopathology; D020257:Ventricular Remodeling
chemical_list: D012333:RNA, Messenger; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D011945:Receptors, Angiotensin