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[Diagnosis of syncopes in suspected arrhythmias]
Insights
Sudden loss of consciousness, often caused by arrhythmias, can be diagnosed using long-term ECG, carotid sinus massage, and exercise stress tests. Electrophysiological investigations help identify ventricular arrhythmias as a cause of syncope.
Area of Science:
- Cardiology
- Electrophysiology
Context:
- Sudden, intermittent loss of consciousness (syncope) can stem from various mechanisms, with arrhythmias being a primary cause.
- Diagnosing the underlying cause of syncope is challenging due to the transient nature of events, often missed by standard ECGs.
Purpose:
- To evaluate the diagnostic utility of various methods, including long-term ECG (LT-ECG), carotid sinus massage, exercise stress testing, and electrophysiological investigations, in identifying arrhythmias as the cause of syncope.
- To highlight the importance of specific electrophysiological parameters and stimulation techniques in diagnosing arrhythmogenic syncope.
Summary:
- Arrhythmias are a major cause of syncope. While routine ECGs are often insufficient, LT-ECG can capture asymptomatic arrhythmias preceding syncope. Carotid sinus massage and exercise stress tests aid in detecting specific types of arrhythmias.
- Electrophysiological investigations, particularly ventricular stimulation techniques, are crucial for inducing and identifying ventricular arrhythmias that may cause syncope. These methods complement traditional diagnostic tools.
Impact:
- This study underscores the necessity of employing a comprehensive diagnostic approach, including LT-ECG, carotid sinus massage, exercise stress testing, and selective electrophysiological studies, to accurately diagnose or exclude arrhythmias in patients experiencing syncope.
- Improved diagnostic accuracy for syncope can lead to timely and appropriate treatment, potentially preventing serious adverse events and improving patient outcomes.
Abstract:
Several mechanisms lead to attacks with unsuspected sudden and intermittent loss of consciousness. A major cause for such syncopes are arrhythmias. Only in rare cases it is possible to register an ECG during a typical attack despite many newer methods as long-term ECG (LT-ECG), exercise stress test and electrophysiologic investigations. LT-ECG does not record the ECG only during symptomatic periods (syncopes, dizziness, palpitations etc), but also registers asymptomatic AR, which can be precursors of SY. Carotid sinus massage is a valuable tool for the detection of a cardio-inhibitory Carotid-Sinus-Syndrome, which can be treated with PM-implantation. Exercise stress testing induces ventricular arrhythmias, which also indicates AR as underlying cause for SY. Using the invasive electrophysiologic investigation methods the importance measuring supraventricular parameters (SNRT, SA-, AH-interval) or parameters of the AV-nodal conduction (AH-, HV-interval) decreased in contrast to the ventricular stimulation techniques. With these invasive procedures ventricular tachycardias, ventricular flutter or fibrillation can be induced in selected patients, which indicates also a possible arrhythmogenic substrate for SY. In a suspected arrhythmogenic genesis of SY it has to be recommended to perform LT-ECG, carotid sinus massage, exercise stress testing and -- in selected patients -- electrophysiological investigations in addition to the routine-ECG to exclude or confirm arrhythmias as possible substrate for SY.