Mobitz Type 1 atrioventricular block: A retrospective assessment of the natural history and need for pacing in 45-64-year-olds.

BACKGROUND

The practice of pacing patients with Mobitz type 1 atrioventricular (AV) block that present with symptomatic bradycardia or who are older than 65 years of age is well established. There is limited evidence that guides the management of younger asymptomatic patients presenting with Mobitz 1 AV block.

OBJECTIVES

To describe the natural history of Mobitz 1 AV block in patients aged 45-64 years, and to assess the need for pacing.

METHODS

This was a retrospective descriptive analysis conducted at Tygerberg Hospital, Cape Town, South Africa. Patients with electrocardiograms (ECG) showing Mobitz type 1 AV block in 2016 were followed up after 6.5 years to observe the natural history of unpaced patients.

RESULTS

A total of 15 141 ECGs and 1506 cardiology admissions were screened. Fifteen patients with Mobitz type 1 AV block were identified and reviewed. There was a near even male to female distribution, 8:7, with a mean age of 59.4 ± 17.8 years. Six patients were aged 45-64 years, and their unpaced (n = 5) 5-year survival rate was 80%. One patient died, but the cause of death was end-stage heart failure and not progression of heart block.

CONCLUSION

Both this study and other notable publications in this field feature small sample sizes. Caution is therefore warranted in drawing definitive conclusions. Nevertheless, our findings suggest a potentially more benign natural history for Mobitz 1 AV block in this age group compared to existing literature.