What is the term for the ECG event that occurs after a sinus pause, where there is an absence of the P wave followed by a very narrow QRS?

The term that describes the ECG event that occurs after a sinus pause, particularly characterized by the absence of the P wave followed by a very narrow QRS complex, is indeed junctional escape beat. This event reflects a scenario where the heart's natural pacemaker (the sinoatrial node) fails to generate an impulse for a brief period, resulting in a pause in normal sinus rhythm.

When the primary pacemaker activity is temporarily absent, the junctional tissue can take over to maintain cardiac rhythm. A junctional escape beat arises from the AV node or the junction between the atria and ventricles. As a result, the characteristic narrow QRS complex reflects that the beat is originating from a higher pacemaker location, and the absence of the P wave indicates that the impulse is not coming from the atria, thus producing a QRS complex without a preceding P wave.

Understanding the specific nature of junctional escape beats helps differentiate them from other arrhythmias. For example, in sinus rhythm, one would expect regular P waves with each QRS complex, which is not the case here. Ventricular escape beats would typically show a wider QRS complex, arising from the ventricles rather than the junctional area. Atrial fibrillation is