What is the recommended management for a patient who develops atrioventricular (AV) block after open or endovascular aortic repair?

Management of AV Block After Aortic Repair

For patients who develop new atrioventricular block after aortic valve surgery (open or transcatheter), permanent pacemaker implantation is recommended before discharge if the AV block is associated with symptoms, hemodynamic instability, or persists beyond 7-10 days. 1

Immediate Post-Procedure Management

Temporary Pacing Infrastructure

• Routine placement of temporary epicardial pacing wires is recommended (Class I) during all open surgical aortic valve replacement or repair procedures. 1
• For transcatheter aortic valve replacement (TAVR), maintain transvenous pacing capability with continuous cardiac monitoring for at least 24 hours after any transient high-grade AV block during valve deployment, regardless of pre-existing conduction disturbances. 1

Risk Stratification by Pre-Existing Conduction Disease

Patients with pre-existing right bundle branch block (RBBB):

• Maintain transvenous pacing ability with continuous cardiac monitoring for at least 24 hours, irrespective of new changes in PR or QRS duration. 1
• The risk of developing high-degree AV block is as high as 24% and exists for up to 7 days post-procedure, with greater latent risk for self-expanding valves. 1
• If transient or persistent procedural high-grade AV block occurs in patients with prior RBBB, permanent pacing is indicated in the vast majority of cases, with anticipated high requirement for ventricular pacing at follow-up. 1
• Consider placement of a durable transvenous pacing lead before leaving the procedure suite in these cases. 1

Patients without pre-existing RBBB who develop new LBBB or PR/QRS prolongation ≥20 ms:

• Continue transvenous pacing for at least 24 hours with continuous cardiac monitoring and daily ECGs during hospitalization. 1
• New-onset LBBB post-TAVR is associated with increased risk of permanent pacemaker implantation (relative risk 1.89) at 1-year follow-up. 1

Timing of Permanent Pacemaker Implantation

Indications for Immediate/Early PPM (Before Discharge)

Permanent pacing is recommended (Class I, Level B-NR) before discharge for: 1

• New postoperative sick sinus node dysfunction or AV block with persistent symptoms
• New postoperative AV block with hemodynamic instability
• AV block that does not resolve after aortic valve surgery

For persistent high-grade AV block:

• Patients with persistent complete AV block should have permanent pacemaker implanted. 1
• If recurrent episodes of transient high-grade AV block occur intraoperatively or postoperatively, PPM implantation should be considered prior to hospital discharge regardless of patient symptoms. 1

Observation Period for Transient AV Block

The critical decision point is 7-10 days postoperatively: 2, 3, 4

• For temporary pacemaker leads, maintain for at least 24 hours to assess for conduction recovery in patients with transient or persistent high-grade AV block. 1
• In transient AV block after congenital heart surgery, 50% resolve by 2 days and 94% resolve by 10 days. 4
• After isolated aortic valve replacement, permanent pacemaker should be implanted after at least 7 days of complete AV block, when it is then considered permanent. 3
• Research from pediatric cardiac surgery suggests limited benefit to delaying PPM placement beyond 10 days, as 94% of transient blocks have resolved by this timeframe. 4

Risk Factors for Permanent AV Block

Independent predictors requiring vigilance include: 3, 5, 4

• Prolonged aortic cross-clamp time (strongest predictor) 3
• Prolonged cardiopulmonary bypass time 3, 4
• Presence of electrolyte disturbances 3
• Endocarditis as indication for surgery 3
• Larger size of implanted valve prosthesis 3
• Baseline first-degree AV block 5
• Baseline left QRS axis deviation 5
• High-risk procedures (e.g., congenitally corrected transposition repair at 27.3%, Konno procedure at 20%, mitral valve replacement at 16%) 2

Post-Discharge Monitoring Strategy (Primarily for TAVR)

For patients with new or worsened conduction disturbances (PR or QRS interval increase ≥10%) after TAVR who do not meet criteria for immediate PPM: 1

• Inpatient monitoring with telemetry for at least 2 days if rhythm disturbance does not progress
• Extend monitoring up to 7 days if ambulatory electrocardiographic monitoring (AEM) will not be employed post-discharge 1
• Provide AEM for at least 14 days post-discharge for any patient with PR or QRS interval that is new or extended by ≥10%. 1
• The monitoring system should have capacity to receive and respond to delayed high-grade AV block within one hour and dispatch appropriate emergency medical services. 1

Rationale for Extended Monitoring

• Delayed high-grade AV block (DH-AVB) can occur in 6-10% of patients with new-onset persistent LBBB after TAVR, with median occurrence at 30 days (range 5-281 days). 1
• The MARE trial demonstrated that among patients with new-onset persistent LBBB after TAVR, 10% required permanent pacing at median 30 days post-procedure. 1

Critical Pitfalls to Avoid

Before attributing AV block to surgical trauma, always rule out reversible causes: 6

• Electrolyte imbalances (particularly hyperkalemia, hypomagnesemia)
• Medications (beta-blockers, calcium channel blockers, digoxin, antiarrhythmics)
• Myocardial ischemia
• Infectious causes

Timing errors:

• Do not implant permanent pacemaker before 7 days unless there is persistent symptomatic or hemodynamically significant AV block, as the majority of transient blocks resolve within this window. 2, 3, 4
• Do not delay beyond 10-12 days if complete AV block persists, as 90% of transient blocks have resolved by this point. 2, 4

Discharge planning errors:

• Do not discharge TAVR patients with new conduction disturbances (PR/QRS increase ≥10%) without either extended inpatient monitoring (up to 7 days) or arrangement for ambulatory electrocardiographic monitoring for at least 14 days. 1
• Ensure recovery location and indwelling vascular access are appropriate for emergent pacing if transvenous pacemaker is removed in high-risk patients. 1