What is the management for a patient with higher degree atrioventricular (AV) block presenting with tiredness?

Management of Higher Degree AV Block with Tiredness

Permanent pacemaker implantation is indicated for patients with higher degree atrioventricular block presenting with tiredness, as this symptom is likely due to bradycardia and hemodynamic compromise from the conduction disorder. 1

Types of AV Block and Clinical Significance

• First-degree AV block: Defined as PR interval >200ms. When severe (PR >300ms), it can cause symptoms of fatigue due to loss of AV synchrony, decreased cardiac output, and increased pulmonary capillary wedge pressure (pseudo-pacemaker syndrome) 1

• Second-degree AV block:

  • Type I (Wenckebach): Usually due to AV nodal delay. Pacing generally not indicated unless patient is symptomatic with fatigue or dizziness 1
  • Type II: Usually infranodal (intra- or infra-His). Associated with frequent symptoms, compromised prognosis, and sudden progression to complete block. Pacing indicated even without symptoms 1
  • 2:1 AV block: Cannot be classified as Type I or II. Can cause fatigue and dizziness, particularly if persistent during exertion 1

• Third-degree (complete) AV block: No conduction from atria to ventricles. Permanent pacing strongly recommended even when ventricular rate >40 bpm 1

Evaluation of Patients with Higher Degree AV Block and Tiredness

• Carefully assess ECG to determine the type and location of block 1
• Consider that ambiguous symptoms like fatigue may be difficult to attribute to bradycardia, requiring special vigilance 1
• Exclude reversible causes before permanent pacing (electrolyte abnormalities, drug toxicity, Lyme disease) 1
• Evaluate for exercise-induced AV block, which usually indicates His-Purkinje disease and poor prognosis 1

Indications for Permanent Pacemaker Implantation

Class I Indications (Definitely Recommended):

• Third-degree and advanced second-degree AV block with symptoms including fatigue 1
• Symptomatic second-degree AV block, regardless of type 1
• First-degree AV block with PR interval >300ms causing symptoms similar to pacemaker syndrome 1, 2

Class IIa Indications (Reasonable):

• Type II second-degree AV block even without symptoms 1
• Asymptomatic third-degree AV block 1
• First-degree AV block with hemodynamic compromise 1, 2

Special Considerations

• For profound first-degree AV block (PR >300ms) causing fatigue, pacing with a shorter AV delay can improve symptoms by restoring proper timing of atrial and ventricular contractions 1, 3
• In patients with bifascicular or trifascicular block with syncope or presyncope, pacemaker implantation is supported even without documented high-degree AV block 1
• For patients on chronic, medically necessary beta-blockers or antiarrhythmic drugs causing symptomatic AV block, permanent pacing is reasonable without waiting for drug washout 1

Pacing Mode Selection

• Dual-chamber pacing is preferred for patients with AV block to maintain AV synchrony 4
• For first-degree AV block with symptoms, programming a shorter AV delay is important 2, 4
• Consider biventricular pacing for patients with first-degree AV block and reduced ejection fraction according to guidelines for cardiac resynchronization therapy 4

Common Pitfalls to Avoid

• Dismissing fatigue as a non-specific symptom when it may be directly related to AV block 1
• Failing to recognize that even first-degree AV block can cause significant symptoms when PR interval is markedly prolonged 2, 3
• Delaying pacemaker implantation in Type II second-degree AV block, which can progress suddenly to complete block 1
• Not considering temporary pacing as a bridge to permanent pacing in unstable patients 1, 5