Mobitz Type I (Wenckebach) AV Block

Mobitz Type I (Wenckebach) AV Block is a heart rhythm condition that affects the electrical signals controlling the heartbeat. It involves the atrioventricular (AV) node, which normally helps coordinate the timing between the upper and lower chambers of the heart. In this condition, the electrical signals slow down progressively until one signal fails to reach the lower chambers, causing a missed heartbeat. This can lead to symptoms like dizziness, fatigue, or feeling like the heart is skipping a beat. The condition primarily affects the cardiac conduction system and can influence how effectively the heart pumps blood. It is often seen in people with underlying heart conditions or those taking certain medications. Understanding this condition helps explain some causes of irregular heart rhythms.

Mobitz Type I (Wenckebach) AV Block is a type of second-degree atrioventricular block characterized by progressive prolongation of the PR interval on electrocardiogram until a non-conducted P wave occurs, resulting in a dropped QRS complex. The core pathology involves impaired conduction through the AV node, often due to increased vagal tone, ischemia, or medications such as beta-blockers or calcium channel blockers. This block is usually benign and transient but can cause symptoms related to transient bradycardia or dropped beats. It is distinguished from Mobitz Type II by the presence of progressive PR interval lengthening before the dropped beat. The clinical significance lies in its potential to cause symptomatic bradyarrhythmias and its association with reversible causes. It is important to recognize because it may require monitoring or adjustment of medications.