The ECG Blog

Sinus Arrest With Atrial Escape

July 1, 2009

Patient: Woman, 55 y/o, using metoprolol. Diabetes Mellitus II, angina pectoris, adipositas. Admitted with general weakness and fatigue, dehydration and dyspnea. Blood pressure is 100/55. No signs of infection.

ECG description:

• Sinus rhythm with sinus arrest
• Axis within the normal quadrant, at ca. 0 degrees
• Poor R wave progression
• Low amplitude in limb leads
• Baseline artefact from patient movement
• T wave flat/inverted in I, aVL

Discussion: After two sinus beats, a two second atrioventricular asystole occurs, which is then terminated by atrial escape. By comparing the escape P wave with the P waves of the three sinus cycles (the two first and the very last on the ecg), we can see that both P wave morphology, axis and PR interval varies slightly. The PR interval in the sinus cycles is 170 ms, while the escape PR interval is 150 ms. This could indicate that the escape pacemaker is atrial ectopic, but is located in the near vicinity of the sinoatrial node. The sinus pause is longer than, but not a multiple of the normal interval, so this is most likely no SA block. There are also no signs of blocked atrial impulses or reciprocating impulses causing the pause. These observations are important to make, as sinus arrest is often confused with SA block and other mechanisms.

Filed under: Bradyarrhythmia, Sinus Node Disorders, T flat/negative, sinus arrest, sinus rhythm

Tags: atrial escape, atrial standstill, av asystole, escape pacemaker, sinus arrest, sinus arrhythmia, sinus pause