From the Guidelines
Complete heart block should be treated with permanent pacemaker implantation as the definitive treatment, regardless of symptoms, due to the high risk of sudden cardiac death and other complications. This recommendation is based on the most recent guidelines from the American College of Cardiology, American Heart Association, and Heart Rhythm Society 1. The treatment approach depends on the severity of symptoms, with temporary pacing often initiated in symptomatic patients using transcutaneous pads or a transvenous pacemaker while preparing for permanent pacemaker implantation.
Key Considerations
- Permanent pacemaker implantation is indicated for third-degree and advanced second-degree AV block at any anatomic level associated with bradycardia with symptoms, ventricular arrhythmias, or other medical conditions that require drug therapy resulting in symptomatic bradycardia 1.
- Asymptomatic patients with complete heart block are also at risk of sudden cardiac death, and permanent pacing should be considered to prevent this complication 1.
- Temporary pacing may be used in emergency situations, but its effectiveness is limited, and medications like atropine or isoproterenol may be used to increase heart rate temporarily.
Treatment Approach
- Symptomatic patients: temporary pacing followed by permanent pacemaker implantation
- Asymptomatic patients: careful monitoring and consideration of permanent pacing to prevent sudden cardiac death
- Emergency situations: temporary pacing and medications like atropine or isoproterenol to increase heart rate temporarily
Important Notes
- Complete heart block represents a failure of electrical impulse transmission from the atria to the ventricles, causing the ventricles to beat at their own inherently slower rate, which is typically insufficient to maintain adequate cardiac output.
- Prompt intervention is essential to prevent complications like syncope, heart failure, or sudden cardiac death.
- The most recent guidelines from the American College of Cardiology, American Heart Association, and Heart Rhythm Society should be consulted for the latest recommendations on the treatment of complete heart block 1.
From the FDA Drug Label
Atropine also may lessen the degree of partial heart block when vagal activity is an etiologic factor In some patients with complete heart block, the idioventricular rate may be accelerated by atropine; in others, the rate is stabilized. Atropine Sulfate Injection, USP, is indicated for temporary blockade of severe or life threatening muscarinic effects, e.g., as an antisialagogue, an antivagal agent, an antidote for organophosphorus or muscarinic mushroom poisoning, and to treat bradyasystolic cardiac arrest.
Atropine may be used to treat complete heart block by potentially accelerating the idioventricular rate or stabilizing it in some patients 2. However, it is essential to note that atropine's effect on complete heart block is not universally predictable and may vary between patients.
- Key considerations:
- Atropine's primary use is for temporary blockade of severe or life-threatening muscarinic effects 2.
- Its effectiveness in treating complete heart block is not guaranteed and should be approached with caution. It is crucial to consult a healthcare professional for proper diagnosis and treatment of complete heart block, as atropine may not be the most appropriate or effective treatment in all cases.
From the Research
Treatment Options for Complete Heart Block
- Permanent pacemaker (PPM) implantation is the standard of care in patients with complete heart block (CHB) and second-degree type II atrioventricular (AV) block irrespective of patient symptoms when the conduction abnormality is irreversible 3
- Implantation of a pacemaker is mandatory for symptomatic children with complete atrio-ventricular block (CAVB) 4
- In asymptomatic neonates and infants, prophylactic pacing is indicated when the ventricular rhythm is <55 beats per minute (bpm) or 70 bpm in case of significant cardiac malformations 4
- Beyond one year of age, PM implantation is recommended in children with an average heart rate <50 bpm or long pauses on 24-hour recordings 4
Pacemaker Implantation After Cardiac Procedures
- Post-operative block that persists 7 days after cardiac surgery is a class I indication for pacing 4
- Patients with residual conduction abnormalities and a long HV interval have a high risk of late sudden death and should be paced 4
- After cardiac surgery, atrial pacing may also be considered, in patients with severe sinus bradycardia and symptoms, or in those requiring antiarrhythmic drugs for tachy-bradycardia syndrome 4
- Ninety-seven percent of patients with persistent high-degree AV/complete block ultimately required pacemaker implantation after TAVR 5
Long-Term Impact of Pacemaker Implantation
- The long-term impact of PPM implantation in patients who undergo alcohol septal ablation (ASA) and develop complete heart block (CHB) remains unclear 6
- Patients who required PPM implantation after ASA had similar baseline characteristics and long-term clinical outcomes compared to those without PPM implantation 6