Dr KK Aggarwal
Recently, the
American College of Cardiology (ACC), the American Heart Association (AHA) and
the Heart Rhythm Society (HRS) have jointly released a guideline for the
evaluation and treatment of patients with bradycardia and cardiac conduction
disorders.
Bradycardia has
been defined in the guideline as a heart rate of less than 50 beats per minute,
compared to a normal heart rate of 50-100 beats per minute. Bradycardia is
generally classified into three categories—sinus node dysfunction,
atrioventricular (AV) block, and conduction disorders. Here are the top 10 take
home messages, reproduced from the guidelines as published in the journal
Circulation.
1.
“Sinus node dysfunction
is most often related to age-dependent progressive fibrosis of the sinus nodal
tissue and surrounding atrial myocardium leading to abnormalities of sinus node
and atrial impulse formation and propagation and will therefore result in
various bradycardic or pause-related syndromes.
2.
Both sleep disorders of
breathing and nocturnal bradycardias are relatively common, and treatment of
sleep apnea not only reduces the frequency of these arrhythmias but also may
offer cardiovascular benefits. The presence of nocturnal bradycardias should
prompt consideration for screening for sleep apnea, beginning with solicitation
of suspicious symptoms. However, nocturnal bradycardia is not in itself an
indication for permanent pacing.
3.
The presence of left
bundle branch block on electrocardiogram markedly increases the likelihood of
underlying structural heart disease and of diagnosing left ventricular systolic
dysfunction. Echocardiography is usually the most appropriate initial screening
test for structural heart disease, including left ventricular systolic
dysfunction.
4.
In sinus node
dysfunction, there is no established minimum heart rate or pause duration where
permanent pacing is recommended. Establishing temporal correlation between
symptoms and bradycardia is important when determining whether permanent pacing
is needed.
5.
In patients with
acquired second-degree Mobitz type II atrioventricular block, high-grade
atrioventricular block, or third-degree atrioventricular block not caused by
reversible or physiologic causes, permanent pacing is recommended regardless of
symptoms. For all other types of atrioventricular block, in the absence of
conditions associated with progressive atrioventricular conduction
abnormalities, permanent pacing should generally be considered only in the presence
of symptoms that correlate with atrioventricular block.
6.
In patients with a left
ventricular ejection fraction between 36% to 50% and atrioventricular block,
who have an indication for permanent pacing and are expected to require
ventricular pacing >40% of the time, techniques that provide more
physiologic ventricular activation (e.g., cardiac resynchronization therapy,
His bundle pacing) are preferred to right ventricular pacing to prevent heart
failure.
7.
Because conduction
system abnormalities are common after transcatheter aortic valve replacement,
recommendations on postprocedure surveillance and pacemaker implantation are
made in this guideline.
8.
In patients with
bradycardia who have indications for pacemaker implantation, shared
decisionmaking and patient-centered care are endorsed and emphasized in this
guideline. Treatment decisions are based on the best available evidence and on
the patient’s goals of care and preferences.
9.
Using the principles of
shared decision-making and informed consent/refusal, patients with
decisionmaking capacity or his/her legally defined surrogate has the right to
refuse or request withdrawal of pacemaker therapy, even if the patient is
pacemaker dependent, which should be considered palliative, end-of-life care,
and not physician-assisted suicide. However, any decision is complex, should
involve all stakeholders, and will always be patient specific
10.
Identifying patient
populations that will benefit the most from emerging pacing technologies (e.g.,
His bundle pacing, transcatheter leadless pacing systems) will require further
investigation as these modalities are incorporated into clinical practice.”
(Source:
Kusumoto FM, Schoenfeld MH, Barrett C, et al. 2018 ACC/AHA/HRS guideline on the
evaluation and management of patients with bradycardia and cardiac conduction
delay: a report of the American College of Cardiology/American Heart
Association Task Force on Clinical Practice Guidelines and the Heart Rhythm
Society. Circulation. 2018; DOI: 10.1161/CIR.0000000000000628)
Dr KK Aggarwal
Padma Shri Awardee
President
Elect Confederation of Medical Associations in Asia and Oceania (CMAAO)
Group Editor-in-Chief IJCP Publications
President Heart Care Foundation of India
Immediate Past National President IMA
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