The pacemaker syndrome occurs when there is a loss of atrio-ventricular synchrony in a patient with a pacemaker. This results in contraction of the atria against closed mitral and tricuspid valves, resulting in hypotension, decreased cardiac output and activation of cardiopulmonary reflexes.


The usual mechanism is single-chamber ventricular pacing with retrograde ventricular-atrial conduction, with contraction of the atria against closed mitral and tricuspid valves.


Signs and symptoms (Hayes, page 935):

(1) weakness, fatigue or lassitude

(2) near syncope or syncope

(3) cough

(4) apprehension

(5) chest pain or precordial distress

(6) hypotension

(7) congestive heart failure

(8) dyspnea

(9) jugular vein pulsations (with cannon A waves)

(10) pounding or fullness in neck or chest

(11) ventricular arrhythmias


Brain natriuretic peptide (BNP) levels may be increased in patients with congestive failure.


Imaging studies show contraction of the atria with closed tricuspid and mitral valves.


If the pacemaker syndrome occurs in a patient with a VVI or VVIR pacemaker, the only definitive treatment is converting to a dual-chamber system.


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