Paroxysmal atrioventricular block: Electrophysiological mechanism of phase 4 conduction block in the His-Purkinje system: A comparison with phase 3 block
| Autor: | Mark E. Josephson, Andrew L. Wit, Mohammad Shenasa |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Male
Bundle of His medicine.medical_specialty 030204 cardiovascular system & hematology Asymptomatic System a Diagnosis Differential Purkinje Fibers Electrocardiography 03 medical and health sciences 0302 clinical medicine Internal medicine Block (telecommunications) medicine Humans 030212 general & internal medicine Atrioventricular Block business.industry Paroxysmal Atrioventricular Block General Medicine Middle Aged Diastolic depolarization Electrophysiology Cardiology medicine.symptom Permanent pacemaker Differential diagnosis Cardiology and Cardiovascular Medicine business |
| Zdroj: | Pacing and Clinical Electrophysiology. 40:1234-1241 |
| ISSN: | 0147-8389 |
| Popis: | BACKGROUND Paroxysmal atrioventricular (A-V) block is relatively rare, and due to its transient nature, it is often under recognized. It is often triggered by atrial, junctional, or ventricular premature beats, and occurs in the presence of a diseased His-Purkinje system (HPS). Here, we present a 45-year-old white male who was admitted for observation due to recurrent syncope and near-syncope, who had paroxysmal A-V block. The likely cellular electrophysiological mechanisms(s) of paroxysmal A-V block and its differential diagnosis and management are discussed. METHODS Continuous electrocardiographic monitoring was done while the patient was in the cardiac unit. RESULTS Multiple episodes of paroxysmal A-V block were documented in this case. All episodes were initiated and terminated with atrial/junctional premature beats. The patient underwent permanent pacemaker implantation and has remained asymptomatic since then. CONCLUSIONS Paroxysmal A-V block is rare and often causes syncope or near-syncope. Permanent pacemaker implantation is indicated according to the current guidelines. Paroxysmal A-V block occurs in the setting of diseased HPS and is bradycardia-dependent. The detailed electrophysiological mechanisms, which involve phase 4 diastolic depolarization, and differential diagnosis are discussed. |
| Databáze: | OpenAIRE |
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