AV Paced Rhythm: ECG/EKG Meaning, Rhythm Strip, Dual-Chamber Pacing

AV Paced Rhythm:

• What is AV Paced Rhythm?
• ECG/EKG Meaning
• Rhythm Strip
• Dual-Chamber Pacing

What is AV Paced Rhythm?

AV paced rhythm refers to a heart rhythm generated by a pacemaker that stimulates both the atria (A) and ventricles (V) in a coordinated manner. This type of pacing is commonly seen in patients with advanced conduction system disease, such as complete heart block or severe bradycardia, where the heart’s natural electrical system cannot reliably transmit impulses from the atria to the ventricles. The pacemaker ensures that atrial contraction is followed by ventricular contraction, maintaining effective cardiac output.

AV pacing is typically achieved using a dual-chamber pacemaker with leads placed in the right atrium and right ventricle. By preserving atrioventricular synchrony, this pacing mode improves hemodynamic performance, reduces symptoms like dizziness or syncope, and enhances exercise tolerance. AV paced rhythms are commonly programmed as DDD, DDDR, or similar pacing modes, depending on patient needs and activity levels.

ECG/EKG Meaning

On an ECG/EKG, an AV paced rhythm is identified by the presence of two pacing spikes: one before the P wave (atrial pacing) and one before the QRS complex (ventricular pacing). The atrial spike triggers atrial depolarization, followed by a paced ventricular depolarization, resulting in a wide QRS complex that resembles a left bundle branch block pattern.

The ECG meaning of an AV paced rhythm is that the pacemaker is successfully sensing and pacing both chambers. This confirms proper device function and effective electrical capture. Clinicians closely examine the timing between atrial and ventricular spikes to ensure appropriate AV delay, which is essential for optimal cardiac filling and output.

Rhythm Strip

A rhythm strip showing an AV paced rhythm will display consistent pacing spikes with regular intervals. The atrial pacing spike is followed by a P wave, and after a programmed AV delay, a ventricular pacing spike precedes a wide QRS complex. The rhythm is usually regular unless rate-responsive features adjust pacing based on patient activity.

Rhythm strips are important for assessing pacemaker function, detecting loss of capture, undersensing, or oversensing. In AV paced rhythms, absence of expected pacing spikes or failure of spikes to produce P waves or QRS complexes may indicate lead dislodgement, battery issues, or changes in myocardial capture thresholds.

Dual-Chamber Pacing

Dual-chamber pacing involves pacing both the atrium and ventricle, allowing the pacemaker to mimic normal cardiac physiology more closely than single-chamber systems. This approach maintains AV synchrony, which improves cardiac efficiency and reduces symptoms associated with atrial-ventricular dissociation.

Patients with sinus node dysfunction combined with AV block benefit most from dual-chamber pacing. While these systems are more complex, they provide superior symptom control, better exercise capacity, and lower risk of pacemaker syndrome compared to single-chamber ventricular pacing. AV paced rhythm on ECG is a direct reflection of this advanced pacing strategy.