# The Subtle Pattern of Sinoatrial Wenckebach

## TL;DR

This paper presents a case of rare SA Wenckebach arrhythmia, highlighting its ECG pattern and clinical management.

## Contribution

The case emphasizes the importance of distinguishing SA Wenckebach from other arrhythmias for accurate diagnosis.

## Key findings

- SA Wenckebach showed grouped beating on ECG with noncompensatory pauses.
- Discontinuing nodal blockers resolved the arrhythmia without pacemaker implantation.
- The case highlights the need for careful ECG interpretation to avoid misdiagnosis.

## Abstract

Second-degree sinoatrial (SA) exit block type I, or SA Wenckebach, is a rare arrhythmia marked by progressively shortening P–P intervals followed by a dropped P wave and a noncompensatory pause, producing a grouped beating pattern on electrocardiogram (ECG).

A 64-year-old male with multiple comorbidities presented after a mechanical fall with bradycardia. ECG revealed a new SA exit block type I. Echocardiography showed preserved ejection fraction and grade II diastolic dysfunction.

Nodal blockers were discontinued, and pacemaker implantation was deemed unnecessary. Recognizing SA exit block is important, as it can mimic atrioventricular block or sinus arrhythmia on ECG.