Unexpected Cause of Syncope

Introduction Sinus node dysfunction (SND) is a common and multifaceted disorder that most commonly occurs in older adults, but can also occur at younger ages due to genetic or other causes. In those aged 45 and older, its prevalence is approximately 1%. Sinus bradycardia is the most common manifestation, but SND may also present with sinus block and prolonged asystole, causing syncope [1,2]. Case Presentation A 52-year-old woman was hospitalized at the LSMU KK Cardiology Clinic due to frequent syncope, mainly occurring while lying down and occasionally sitting. Prodromal symptoms included weakness, cold sweats, nausea, an urge to urinate, and an unpleasant smell in her surroundings. Witnesses reported a 30-second loss of consciousness. Syncope episodes had persisted for two years but recently increased to daily or several times weekly. An outpatient tilt table test with nitroglycerin provocation revealed a drop in blood pressure to 40/20 mmHg at the 5th minute. Atrioventricular rhythm was observed: HR 34 bpm with a pause of up to 5 seconds. This was assessed as cardioinhibitory syncope, type 2A. However, indications for a pacemaker were insufficient due to the predominance of the vasodepressor mechanism. Echocardiographic examination, Holter monitoring, brain MRI, EEG, BKT, laboratory tests - without significant changes ECG: SR, HR 81 bpm. T (-) III, aVF. PR 146 ms, QRS 94 ms. QT/QTc 354/391 ms.. Family History: sudden cardiac deaths occurred in close family members around the age of 50. During hospitalization, telemetry recorded a few 17–19 second asystole episodes with prodromal symptoms and syncope. A dual-chamber pacemaker was implanted. Due to the possibility of familial progressive cardiac conduction disease genetic testing was recommended. 17 sec. asystole Discussion SND symptoms vary from asymptomatic ECG changes to severe manifestations like syncope. Genetic mutations in SCN5A, HCN4, CASQ2, and RYR2 may contribute to SND, often linked to rhythm and conduction issues and sudden cardiac death risk. Genetic testing is crucial for identifying affected families [2]. Conclusions SND is a significant and potentially dangerous cardiac cause of syncope, especially in cases with documented episodes of asystole or prolonged pauses in the medical history. Timely diagnosis and pacemaker implantation can prevent sudden cardiac death.