The Effects of Ventricular Tachycardia on Carotid Artery Blood Flow Velocity

Benchimol, Alberto; Baldi, Jose; Desser, Kenneth B.

doi:10.1161/01.str.5.1.60

Cited by 9 publications

(2 citation statements)

References 19 publications

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“…Among these, PAF may reduce cardiac output and hence perfusion pressure to levels that compromise the cerebral circulation with consequent signs of hemodynarnic ischemia [5,9,15]. This phenomenon, known as autoregulation, prevents the onset of cerebral ischemia even when there are wide variations in perfusion pressure.…”

Section: Discussionmentioning

confidence: 99%

Transcranial Doppler evaluation of cerebral blood flow in patients with paroxysmal atrial fibrillation

et al. 1993

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Cerebral blood flow was measured by transcranial Doppler sonography (TCD) in 15 patients during and after an attack of paroxysmal atrial fibrillation. During the attack the mean flow velocity (MFV) was reduced significantly in the middle cerebral artery (p < 0.05) and nonsignificantly in the other arteries. The pulsatility index (PI) was reduced in all the arteries but not significantly. During the fibrillation phase the MFV and PI tended to decrease as the heart rate increased. None of the patients showed clinical signs of cerebral ischemia during the attacks. The absence of such signs despite the reduced cerebral blood flow in atrial fibrillation is probably due to the activation of mechanisms of autoregulation.

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Section: Discussionmentioning

confidence: 99%

Transcranial Doppler evaluation of cerebral blood flow in patients with paroxysmal atrial fibrillation

et al. 1993

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“…A chronic reduction of brain blood flow due to repetitive arrhythmias probably produces neuronal damage in poststenotic tissue regions [31]. Because cerebral blood flow (CBF) measurements are difficult and seldom ethically justified during acute ventricular arrhythmias in patients [2,3,6], an experimental rat model was established to quantify the hemodynamic effects of hypotensive tachycardias on regional CBF in the presence of common carotid artery occlusion.…”

Section: Abstract: Cerebral Blood Flow -Carotid Stenosis -Microsphermentioning

confidence: 99%

Carotid artery stenosis and tachyarrhythmias: regional cerebral blood flow during high-rate ventricular pacing after one vessel occlusion in rats

et al. 1994

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The aim of the present study was to investigate the effect of hypotensive tachycardias on cerebral blood flow (CBF) in the presence of significant carotid stenosis. The experiments were performed in 57 spontaneously breathing rats during arterial normoxia and normocapnia anesthetized with thiobarbital. CBF was determined with radiolabeled microspheres during control conditions (normofrequent sinus rhythm, normotension; group A; n = 15), during high-rate left ventricular pacing (660-840 ppm) at normotension (group B1; n = 13), borderline hypotension (group B2; n = 15) and severe hypotension (group B3; n = 7). In addition, CBF measurements were performed during borderline hypotension induced by hemorrhage (group C; n = 7). Global CBF was 1.09 +/- 0.29 ml g-1 min-1 in group A, 0.93 +/- 0.40 in group B1, 0.68 +/- 0.31 in group B2 (P < 0.05 vs. A), 0.42 +/- 0.16 in group B3 (P < 0.05 vs. A) and 0.83 +/- 0.2 in group C. The highest CBF values were found in the cerebellum (A; 1.43 +/- 0.5 ml g-1 min-1) and the lowest in the postocclusive tissue of the ipsilateral hemisphere (A; 0.74 +/- 0.2 ml g-1 min-1). In all groups a 15% mean CBF reduction in the right hemispherical cerebrum in comparison to the left hemisphere was observed (P < 0.01). In contrast, hemispherical CBF of the cerebellum did not differ. The CBF blood pressure relationship shifted to lower CBF values, the threshold of CBF regulation shifted to higher blood pressure values in the tissue regions distal to the occluded vessel during hypotensive tachycardias.(ABSTRACT TRUNCATED AT 250 WORDS)

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