Is Mobitz type I atrioventricular block benign in adults?

Area of Science:

• Cardiology
• Electrophysiology
• Internal Medicine

Background:

• Chronic Mobitz type I second degree atrioventricular block (Mobitz I) can affect adults.
• The necessity of pacemaker implantation in these patients requires further investigation.

Purpose of the Study:

• To evaluate the indications and outcomes of pacemaker implantation in adults with chronic Mobitz I block.
• To assess the survival rates and adverse events in paced versus unpaced patients.

Main Methods:

• A prospective study was conducted at a district general hospital involving 147 adult subjects with chronic Mobitz I block.
• Patients were followed up to assess outcomes including death, conduction deterioration, and symptomatic bradycardia.
• Pacemakers were implanted in 90 patients, primarily for symptoms (74) and prophylaxis (16).

Main Results:

• Five-year survival was significantly reduced in unpaced patients compared to the normal population.
• Paced patients demonstrated improved survival rates compared to unpaced patients, particularly those with organic heart disease.
• Survival rates were notably lower in patients aged 45 and above, with only the younger cohort and those with sinus arrhythmia showing over 50% survival.

Conclusions:

• Chronic Mobitz I block is generally not benign in patients aged 45 years and older.
• Pacemaker implantation should be considered even in the absence of symptomatic bradycardia or organic heart disease.
• This suggests a more aggressive approach to pacing may be warranted for selected patients with Mobitz I block.