| Modulation of the arterial coronary blood flow by asynchronous activation with ventricular pacing. | |
| | |
MedLine Citation:
|
PMID: 7596853 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
This study aims to test the assumptions that: (1) coronary arterial flow is attenuated in an early activated region by ventricular pacing; (2) asynchronous mechanical activation caused by ventricular pacing under controlled perfusion pressure and intact coronary tone is associated with reduced coronary flow compared to atrial pacing; and (3) abolishment of vascular tone under controlled perfusion pressure diminishes the expected difference in blood flow between atrial and ventricular pacing. Blood flow velocity (BFV) in the left anterior descending (LAD) and the left circumflex arteries (CFX) and a wall thickening index were measured in 14 open-chest dogs under normal conditions, and constant perfusion pressure. Four pacing sites were used: right atrium (RAp), mid-right ventricle (RVp), mid-left ventricle (LVp), and left ventricular apex (Apexp). Pacing modes were either sequential ventriculoatrial (VA) (protocol A, n = 7), or sequential atrioventricular (AV) (protocol B, n = 7), with a shorter AV difference (30 msec) than normal. Results: BFV was decreased in the LAD during RVp and Apexp pacing by 9.7%-12.9% versus RAp and by 11.6%-14.6% versus LVp (P < 0.05). No BFV variations were observed in the CFX. Flow velocity conductance (FVC = mean blood flow velocity divided by the mean aortic pressure) was higher by 16%-28% in the CFX for the three ventricular pacing sites versus the atrial pacing, and higher by 14.1% +/- 6.1% only in LVp versus RAp pacing in the LAD (P < 0.05). Wall thickening index reduced during ventricular pacing in all three ventricular sites by 50%-64% (P < 0.05) compared to atrial pacing. Under constant perfusion pressure, LAD blood flow decreased with ventricular pacing as compared to right atrial pacing; this was particularly pronounced during the diastolic phase (16.6%-45.5%, P < 0.02). Normalized oscillatory flow amplitude (OFAn) was reduced in RVp pacing compared to RAp and LVp pacing (16.2 +/- 3.5 and 21.7% +/- 4.1%, respectively, P < 0.03). The variations in blood flow and OFAn disappeared with adenosine-mediated maximum vasodilatation. Summary: (1) Mean and phasic flows are reduced in the early activated LAD region by ventricular pacing (RVp, Apexp). (2) Under controlled perfusion pressure and intact vascular tone, ventricular pacing compromises blood flow compared with atrial pacing. (3) This effect disappears when vascular tone is eliminated by intracoronary injection of adenosine, suggesting that the coronary autoregulation is responsible for some of the effects. |
| | |
Authors:
|
G Amitzur; D Manor; A Pressman; D Adam; H Hammerman; R Shofti; R Beyar; S Sideman |
Related Documents
:
|
7211673 - Dependence of ventricular fibrillation propensity on coronary blood flow without myocar... 7074793 - Effects of digitalis on subendocardial and subepicardial dysfunction during acute ische... 12650413 - Pathophysiology of headache associated with cough in patients with chiari i malformation. |
Publication Detail:
|
Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
|
Title: Pacing and clinical electrophysiology : PACE Volume: 18 ISSN: 0147-8389 ISO Abbreviation: Pacing Clin Electrophysiol Publication Date: 1995 Apr |
Date Detail:
|
Created Date: 1995-07-28 Completed Date: 1995-07-28 Revised Date: 2006-11-15 |
Medline Journal Info:
|
Nlm Unique ID: 7803944 Medline TA: Pacing Clin Electrophysiol Country: UNITED STATES |
Other Details:
|
Languages: eng Pagination: 697-710 Citation Subset: IM |
Affiliation:
|
Neufeld Cardiac Research Institute, Sheba Medical Center, Tel Hashomer, Israel. |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Animals Cardiac Pacing, Artificial* / methods Coronary Circulation / physiology* Dogs Electrocardiography Female Heart Atria Heart Ventricles Male |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Echocardiographic assessment of epicardial defibrillator patch electrodes.
Next Document: Transvenous cardioverter defibrillators: cost implications of a less invasive approach.