Cardiovascular Journal of Africa: Vol 32 No 1 (JANUARY/FEBRUARY 2021)

CARDIOVASCULAR JOURNAL OF AFRICA • Volume 32, No 1, January/February 2021

AFRICA

A comparison of AAIR versus DDDR pacing for patients

with sinus node dysfunction: a long-term follow-up study

Reuben Kato Mutagaywa, Basil Tumaini, Ashley Chin

Abstract

Objectives:

The aim of the study was to compare the clini-

cal outcomes [atrial fibrillation (AF), atrio-ventricular (AV)

block, device sepsis and lead revision] of patients with sinus

node dysfunction (SND) between atrial-pacing atrial-sensing

inhibited-response rate-adaptive (AAIR) versus dual-cham-

ber rate-adaptive (DDDR) pacing. The choice of AAIR

pacing versus DDDR pacing was determined by AV nodal

functional testing at implant.

Methods:

We conducted a retrospective review of consecutive

patients who underwent AAIR and DDDR pacing over a

10-year period.

Results:

One hundred and sixteen patients required pacing

for symptomatic SND. Fifty-four (46.6%) patients received

AAIR pacemakers and 62 (53.4%) received DDDR pacemak-

ers based on AV nodal functional testing at implant. Patients

who had AV Wenkebach with atrial pacing at 120 beats per

minute received DDDR pacing. Overall the mean age of

patients with SND was 65 years and 66.4% were females,

30% were diabetics and 71% were hypertensives. Pre-syncope/

syncope (84%) and dizziness (69%) were the most common

symptoms. Sinus pauses and sinus bradycardia were the most

common ECG manifestations. Over a median follow up of

five (IQR: 2–11) years, four patients (7.4%) developed AF

in the AAIR group compared to three (4.8%) in the DDDR

group (

= 0.70). AV block occurred in one patient in the

AAIR group, who required an upgrade to a DDDR pace-

maker. There was no difference in device sepsis or need for

lead revision between the two groups.

Conclusion:

We found that AV nodal functional testing with

atrial pacing at the time of pacemaker implantation was a

useful tool to help guide the implanter between AAIR or

DDDR pacing. Patients who underwent AAIR pacing had a

low risk of AF, AV block or lead revision. In resource-limited

settings, AAIR pacing guided by AV nodal functional testing

should be considered as an alternative to DDDR pacing.

Keywords:

cardiac pacing, sinus node dysfunction, single-lead

atrial pacing, dual-chamber pacing, atrial fibrillation, atrio-

ventricular block

Submitted 17/6/20, accepted 30/8/20

Published online 18/9/20

Cardiovasc J Afr

2021;

: 17–20

www.cvja.co.za

DOI: 10.5830/CVJA-2020-040

Symptomatic sinus node dysfunction (SND), also known as sick

sinus syndrome, is usually due to age-related degeneration of

the sinus node. SND can manifest on the ECG as a variety of

ECG abnormalities, including sinus bradycardia, sinus arrest,

sino-atrial block, chronotropic incompetence and the tachy–

brady syndrome.

The most common symptoms of SND include

syncope, dizzy spells, fatigue and exercise intolerance due to

chronotropic incompetence.

A diagnosis of symptomatic sinus node dysfunction requires

correlation of symptoms with ECG findings. Secondary or

reversible causes of SND may require specific treatment. The

only treatment for primary symptomatic SND, usually due

to age-related degeneration, is the insertion of a permanent

pacemaker. SND is the second most common cause for cardiac

pacing, accounting for approximately 30% of all pacemaker

implantations.

The indications and modes for pacemaker implantation

for SND have been published. Both the European Society

of Cardiology (ESC) guidelines

and the American College

of Cardiology (ACC)/American Heart Association (AHA)

guidelines

recommend dual-chamber rate-adaptive (DDDR)

pacing over atrial-pacing atrial-sensing inhibited-response rate-

adaptive (AAIR) pacing. This recommendation is based on

the subsequent risk of atrio-ventricular (AV) block, a higher

risk of paroxysmal atrial fibrillation (AF) and the higher risk

of complications with AAIR pacing in patients who require

subsequent ventricular pacing.

However, the numbers of

patients who develop these complications are low, and with

the higher cost of DDDR pacing, the initial increased risks

of the additional ventricular lead, together with the harmful

effects of inappropriate ventricular pacing, AAIR pacing has

remained a reasonable option for patients with SND, especially

in resource-limited settings.

This is particular relevant for

developing countries in Africa where pacemaker implanters

implant mainly single-chamber pacemakers because of cost

and expertise.

The future development of AV block has been recognised as

a potential problem with AAIR pacing. The incidence of AV

block in patients with SND has been reported to range from

< 1% to 4.5% per year.

9–13

In an observational study of AAIR and

DDDR pacing with long-term follow up, the annual incidence

of AV block in the AAIR group was low (1.1%). Atrial pacing

with an AV Wenckebach rate lower than 120 beats per minute

(bpm) was found to be a predictor of high-grade AV block.

The

DANPACE study, the largest randomised study of AAIR versus

Department of Internal Medicine, School of Medicine,

Muhimbili University of Health and Allied Sciences, Dar es

Salaam, Tanzania

Reuben Kato Mutagaywa, MD, MMed, MSc, reubenmutagaywa@

yahoo.com

Basil Tumaini, MD, MMed

Department of Medicine, Faculty of Health Science,

University of Cape Town, South Africa

Reuben Kato Mutagaywa, MD, MMed, MSc

Ashley Chin MBChB, MPhil