Cardiac monitoring for patients with palpitations

Table 1 Principal cardiac and noncardiac causes of palpitations

	Cardiac and noncardiac causes
Cardiac arrhythmias	Premature contractions (supraventricular or ventricular)
	Supraventricular tachycardia (AF, flutter, AVRNT, etc.)
	Ventricular tachycardia
	Severe bradyarrhythmia/AV block
	Pacemaker mediated tachycardia
Structural heart disease	Severe aortic regurgitation
	Hypertrophic cardiomyopathy
	Congenital heart disease with significant shunt
	Mechanical prosthetic valves
Systemic causes	Thyroid dysfunction
	Pheochromocytoma
	Anaemia
	Fever
	Hypoglycaemia
	Arteriovenous fistula
	Autonomic dysfunction
Psychosomatic disorders	Anxiety
	Somatisation disorder
Drugs	Sympathomimetic agents (bronchodilators, antidepressants)
	Vasodilators (hydralazine, doxazosin)
	Recreational: Cocaine, alcohol, amphetamines, cannabis

AVRNT: Atrioventricular nodal re-entry tachycardia; AF: Atrial fibrillation; AV: Atrioventricular.

Table 2 Main advantages, limitations, and indications of the most commonly used models of cardiac monitoring devices

	Advantages	Disadvantages	Main indications
24 h Holter	Continuous recording	Discomfort for the patient	Very frequent (daily) symptoms
	12 leads with good correlation with surface ECG	Artefacts	Permanent AF rate monitoring
	Low economic cost	Maximum recording of 24-48 h (low diagnostic yield)	Frequent ventricular premature beats
			Risk stratification of (hypertrophic) cardiomyopathies
Skin patches	Continuous recording of 7–14 d	Single use and greater economic cost	Frequent (weekly) symptoms
	Good tolerability for patients	Analysis by external companies	AF detection in cryptogenic stroke (2 wk)
		Only one lead1
External loop recorders	Loop recording (includes beginning and end of arrhythmic event)	Patient discomfort	Occasional symptoms (monthly)
	4 wk monitoring	Requires education from healthcare professional on how to correctly place the electrodes	AF detection in cryptogenic stroke (2–4 wk)
	High yield and efficiency in the assessment of palpitations
Implantable loop recorder	Loop recording	Invasiveness and associated complications (infection, bleeding, etc.)	Very infrequent symptoms
	Up to 3-yr monitoring (good diagnostic yield)	Individual economic cost	AF detection in at-risk patients (cryptogenic stroke, post-ablation, etc.)
	Patient does not have to do anything	Single lead	Syncope
	Remote monitoring
External event recorders/mobile devices	Easy access for the general population	Single lead1	Palpitations work-up
	Possibility of prolonged use (years)	Data management	Population AF screening (not validated)
	Screening for asymptomatic events (AF screening)	Patient has to be involved (not suitable for syncope work-up)
	Remote monitoring

¹There are devices with more leads.

AF: Atrial fibrillation; ECG: Electrocardiogram.

Table 3 Summary of relevant studies on diagnostic yield for palpitations according to the different types of devices

Ref.	No. of patients	Study design	Study population	Duration of monitoring	Diagnostic yield	Other findings
Holter 24 h
Sulfi et al[22], 2008	2688	Retrospective cohort	Palpitations and basal sinus rhythm	24 h	16%	Even less diagnostic yield in patients aged < 50 yr
Paudel et al[103], 2013	335	Single-center prospective cohort	Palpitations	24 h	75%	40% of patients with ventricular ectopy considered as diagnostic finding (possible selection bias)
ECG patchs
Barrett et al[59], 2014	146	Prospective cohort comparing Patch vs 24 h Holter	Palpitations	15 d	60% more diagnostics than 24 h Holter	Over 90% of patients were comfortable with it. Best diagnostic yield during first week
Event recorders
Narasimha et al[104], 2018	38	Prospective cohort comparing Kardia Mobile vs ELR (simultaneously)	Palpitations (less often than daily but more than monthly)	14–30 d	89.5% vs 68% in ELR group	Better compliance with Kardia Mobile
Hall et al[63], 2020	11 studies (> 20000 patients)	Systematic review	AF screening in general population	Heterogeneous	Up to 36% (depending of population’s AF burden)	More diagnostic yield in people aged > 65 yr. Approximately 4% of uninterruptable registries
ELR
Locati et al[54], 2016	392 (282 with palpitations)	Prospective cohort	> 2 episodes in last year	4 wk	71.6%	Early recorder use increase diagnostic yield. Diagnostic yield for syncope: 24.5%
Francisco-Pascual et al[2], 2019	149 (91 in ELR group)	Prospective ELR cohort compared with historical Holter cohort	> 2 episodes in last year	21 d	86.8%	Holter diagnostic yield: 20.7%. ELR reduce the cost per diagnosis
ILR
Giada et al[29], 2007	50 (26 in ILR group)	Prospective cohort comparing ILR with conventional strategy	1 episode per month or less (longer than 1 min)	321 d (mean)	73%	Mean time to diagnosis: 279 d. Lower cost per diagnosis in ILR group
Padmanabhan et al[83], 2019	312 (51 with palpitations)	Prospective cohort of consecutive patients with an ILR implanted	Any indication form monitoring (16.3% due to palpitations)	579 d (mean)	64.7%	38.7% useful in ruling out an arrhythmic cause for symptoms (all indications). 12% AF.

ELR: External loop recorders; AF: Atrial fibrillation; ILR: Implantable loop recorders.