sinuspause

Sinuspause, also called sinus pause, is a temporary cessation of impulse generation by the heart’s sinoatrial (SA) node, resulting in a brief pause in heart rhythm. On an electrocardiogram, a sinuspause appears as a gap between two consecutive carried beats, during which no P waves or QRS complexes are recorded. After the pause, normal SA node activity typically resumes, or an escape pacemaker from the atrioventricular node or surrounding tissue may take over to maintain rhythm.

The phenomenon is often discussed as part of sinus node dysfunction. Short pauses may reflect normal variation or transient changes in autonomic tone, while longer pauses can indicate impaired SA node automaticity. If the SA node fails for an extended period, an escape rhythm from a lower pacemaker may bypass the pause and produce a slower, regular rhythm.

Causes of sinuspause include aging-related degeneration of the SA node, ischemic heart disease, infiltrative or fibrotic diseases affecting the node, and structural heart disease. Medications such as beta-blockers, non-dihydropyridine calcium channel blockers, digoxin, and certain antiarrhythmics can contribute. Other factors include electrolyte disturbances, heightened vagal tone, sleep apnea, and acute medical illnesses.

Clinical presentation ranges from asymptomatic to dizziness, lightheadedness, near-syncope, or syncope, particularly with longer or recurrent pauses. Diagnosis relies on ECG and ambulatory monitoring (Holter or event monitors) to document the pauses and assess their duration and frequency.

Management targets the underlying cause and symptom burden. Medication adjustments may reduce pauses; symptomatic or high-grade pauses often require pacing, with permanent pacemaker therapy being a common treatment for sick sinus syndrome or recurrent, troublesome sinuspause.