Flow disturbances in carotid and vertebral arteries in symptomatic patients referred for pacemaker implantation

Electrocardiographic abnormalities and clinical symptoms are used as indications for cardiac pacing. Syncope, faints and other neurological symptoms are of multi-factorial origin and are due to reduced brain perfusion.

To examine the carotid and vertebral artery blood flow and to assess whether stenosis of these arteries is associated with symptoms of cerebral hypoperfusion in patients undergoing pacemaker implantation.

In 152 consecutive patients (84 men, age 70.6+/-10 years), admitted for pacemaker implantation from January 2003 to June 2004, ultrasonographic and colour Doppler examinations of the carotid and vertebral arteries were performed. The patient's medical history and symptoms, conduction disturbances, and modes of pacing were evaluated using a uniform questionnaire. Clinical manifestations of atherosclerosis were present in 21% (remote myocardial infarction) and 8% (stroke) of patients. Patients were divided into 2 groups: asymptomatic subjects (25%) and those with symptoms of cerebral hypoperfusion (75%).

There were no significant differences in indications and modes of pacing between the groups; only second degree atrioventricular block was significantly more frequent in patients without symptoms (p=0.0163). Prevalence of either common or internal carotid artery stenosis>50% was higher in symptomatic than asymptomatic patients (32 vs. 16, p<0.05). Multivariate analysis revealed a 3.5 times higher probability of Stokes-Adams attacks and syncope in patients with confirmed atherosclerotic lesions (OR 3.5, 95% CI 1.2-13.4; p=0.0351). Blood flow disturbances in vertebral arteries were more frequent in symptomatic patients: 26 vs. 11%, p=0.0438. The lowest risk of loss of consciousness was observed in patients with second degree atrioventricular block, with no atherosclerotic lesions: (OR 0.2; 95% CI 0.03-0.06; p=0.0102).

Prevalence of atherosclerotic lesions in carotid and vertebral arteries is higher in symptomatic patients referred for pacemaker implantation. The lowest risk of symptoms was found in patients with a second degree atrioventricular block and no atherosclerotic lesions. Ultrasonographic examination of carotid and vertebral arteries should be considered in all symptomatic patients with indications for pacemaker implantation.