Pseudopacemaker syndrome and marked first-degree atrioventricular block: Case report

Abstract

Introduction. Pacemaker syndrome consists of the symptoms and signs present in the single chamber (VVI) pacemaker patient with electrode placed in the right ventricular apex. It is caused by inadequate timing of atrial and ventricular contractions. Pacemaker syndrome without a pacemaker (or pseudopacemaker syndrome) refers to occurrence of symptoms in the presence of marked first-degree atrioventricular (AV) block, when P wave is too close to the preceding QRS complex producing the same haemodynamic disturbance as artificial pacemaker cardiac stimulation with retrograde VA conduction. Case Outline. We present the patient with acute inferior myocardial infarction due to late bare metal stent thrombosis, treated with primary pectutaneous coronary intervention. Hospital course was complicated by complete heart block which was treated with temporary pacing. During the stand-by mode of temporary pacing, sinus rhythm with marked first-degree AV block (PQ interval 480 ms) was observed while the patients re-experienced the symptoms that were present prior to pacemaker implantation. Temporary pacing was continued for the next 24 hours when spontaneous shorteninig of PQ interval (250-270 ms) was noticed; since the patient was asymptomatic during the stand-by mode, the pacemaker electrodes were removed and the patient discharged 11 days after admission. Conclusion. Conduction disturbances, such as the varying degrees of AV blocks, are relatively common in acute inferior myocardial infarction. The first degree AV blok is usually asymptomatic and does not require treatment, unless when it is associated with pseudopacemaker syndrome. In that case, temporary pacing provides haemodynamic stability until conduction system recovers.

Keywords

• pseudopacemaker syndrome
• atrioventricular block
• acute myocardial infarction