Asymptomatic Bradyarrhythmias may not require any treatment, needless pacemaker therapy: JAMA
A groundbreaking post hoc analysis of the Implantable Loop
Recorder Detection of Atrial Fibrillation (AF) to Prevent Stroke (LOOP) trial
has unearthed a previously underestimated prevalence of bradyarrhythmias in
individuals aged 70 and above with cardiovascular risk factors. The study
concluded that one in five individuals over 70
years old with cardiovascular risk factors may have bradyarrhythmias when
subjected to long-term continuous monitoring for AF.
The study results were published in the journal
JAMA Cardiology.
Growing attention is directed towards heart rhythm monitoring
and technologies aimed at identifying subclinical atrial fibrillation (AF),
potentially resulting in the inadvertent discovery of bradyarrhythmias. Hence,
researchers conducted a Post Hoc analysis of the LOOP randomized trial to investigate
the impact of long-term continuous monitoring for atrial fibrillation (AF)
using an implantable loop recorder (ILR) compared to standard care across four
sites in Denmark.
Between January 2014 and May 2016, the trial enrolled 6004
participants, all aged 70 or older, with conditions such as hypertension,
diabetes, heart failure, or prior stroke. The focus was on evaluating
bradyarrhythmia diagnoses, pacemaker implantations, syncope events, and sudden
cardiovascular deaths over a median follow-up period of 65 months.
Findings:
Intriguingly, the ILR screening group, comprising 1501
participants, exhibited a staggering 6.21-fold increase in bradyarrhythmia
diagnoses compared to the control group (4503 participants), where only 3.8%
received such a diagnosis.-
Significantly, a large proportion of bradyarrhythmia cases in
the ILR group (79.8%) were asymptomatic, highlighting the potential value of
continuous monitoring in capturing silent cardiac irregularities.
The most prevalent types of bradyarrhythmias identified were
sinus node dysfunction and high-grade atrioventricular block.Age, male gender, and a history of prior syncope were identified
as risk factors associated with bradyarrhythmias.
Notably, the ILR screening group experienced a noteworthy
increase in pacemaker implantations (4.5%) compared to the control group
(2.9%).-
However, there was no discernible difference in the occurrence
of syncope or sudden cardiovascular death between the two groups.
Bradyarrhythmias, identified through continuous monitoring, were
found to be correlated with subsequent syncope, cardiovascular death, and
all-cause mortality.
Crucially, the impact of bradyarrhythmia on these outcomes
remained consistent across both the ILR and control groups.
In conclusion, this study suggests that more than one in five
individuals over 70 years old with cardiovascular risk factors may have
bradyarrhythmias when subjected to long-term continuous monitoring for AF. The
utilization of ILR screening significantly heightened the detection of
bradyarrhythmias and led to more pacemaker implantations compared to standard
care. While shedding light on this hidden aspect of cardiac health, the study
underscores the need for comprehensive heart rhythm monitoring, offering
invaluable insights for diagnostic and therapeutic considerations in managing
cardiovascular health in the elderly.
Further reading: Diederichsen SZ, Xing LY, Frodi DM, et al. Prevalence and Prognostic Significance of Bradyarrhythmias in Patients Screened for Atrial Fibrillation vs Usual Care: Post Hoc Analysis of the LOOP Randomized Clinical Trial. JAMA Cardiol. 2023;8(4):326–334. doi:10.1001/jamacardio.2022.5526
