What causes palpitations?

Causes of Palpitations

Palpitations arise from cardiac arrhythmias, structural heart disease, psychiatric conditions (especially anxiety), medications/substances, systemic diseases, or remain unexplained in up to 16% of cases. 1, 2

Cardiac Arrhythmias (Most Important to Identify)

Benign Arrhythmias

• Premature ventricular contractions (PVCs) are the most common ventricular cause, typically benign when isolated, suppressed with exercise, and occurring without structural heart disease 3, 1
• Premature atrial contractions cause the sensation of skipped beats or pauses followed by strong compensatory beats 1
• Sinus tachycardia presents with gradual onset/offset and is often physiologic 1

Supraventricular Arrhythmias

• Atrioventricular nodal reentrant tachycardia (AVNRT) characteristically causes sudden onset and sudden termination (paroxysmal pattern) 1
• Atrial fibrillation produces irregular palpitations and is the most common arrhythmia requiring hospitalization 3, 1
• Atrial flutter causes regular rapid palpitations 3
• Multifocal atrial tachycardia occurs predominantly in patients with underlying pulmonary disease 1

Ventricular Arrhythmias (Highest Risk)

• Ventricular tachycardia is particularly concerning in patients with structural heart disease and may present with palpitations, dyspnea, chest pain, or syncope 3, 1
• Very frequent PVCs (>10,000-20,000/day) can cause PVC-induced cardiomyopathy, which is reversible with arrhythmia control 1

Pathophysiological Mechanisms

The three fundamental mechanisms generating arrhythmias that cause palpitations are:

• Re-entry (most common): abnormal circular conduction pathways allowing sustained arrhythmias 1
• Enhanced automaticity: abnormal pacemaker activity in cardiac cells 1
• Triggered activity: disturbances in repolarization causing afterdepolarizations, responsible for torsades de pointes in long QT syndrome 3, 1

Structural Heart Disease (Non-Arrhythmic Cardiac)

• Mitral valve prolapse can cause palpitations even without arrhythmias 3, 2
• Cardiomyopathies (dilated, hypertrophic, arrhythmogenic right ventricular) predispose to ventricular arrhythmias 3
• Coronary artery disease and ischemia trigger ventricular ectopy 3
• Congestive heart failure causes palpitations through multiple mechanisms 2
• Pericarditis produces palpitations independent of rhythm disturbances 2

Psychiatric and Psychological Causes

• Anxiety disorders are the most common non-cardiac cause of palpitations 4, 5
• Panic disorder frequently presents with palpitations as a cardinal symptom 5, 6
• Important caveat: Even when psychiatric comorbidity exists, do not assume palpitations are non-cardiac without proper cardiac evaluation 5

Systemic Non-Cardiac Diseases

• Hyperthyroidism increases heart rate and can precipitate atrial fibrillation 3
• Hypoglycemia triggers catecholamine release causing palpitations 2
• Anemia increases cardiac output and heart rate 4
• Fever and infection cause physiologic sinus tachycardia 4
• Electrolyte abnormalities (hypokalemia, hypomagnesemia) predispose to arrhythmias 3
• Pheochromocytoma (rare) causes catecholamine-mediated palpitations 4

Medications and Substances

Prescription Medications

• QT-prolonging drugs (antiarrhythmics, certain antibiotics, antipsychotics) can cause torsades de pointes 3
• Beta-agonists (albuterol) increase heart rate 2
• Thyroid hormone replacement in excess causes palpitations 2
• Paradoxically, beta-blockers themselves list palpitations as an adverse effect in ~1% of patients 7

Substances and Stimulants

• Caffeine is a common trigger for palpitations 2, 6
• Alcohol can precipitate atrial fibrillation ("holiday heart syndrome") 2
• Cocaine and amphetamines cause catecholamine surge and arrhythmias 3
• Nicotine increases sympathetic tone 2
• Over-the-counter decongestants (pseudoephedrine) stimulate the cardiovascular system 2

Special Populations

Pregnancy and Postpartum

• Physiologic changes in pregnancy increase blood volume and heart rate, making palpitations extremely common 3, 8
• Supraventricular tachycardia symptoms increase during pregnancy 3, 8
• Postpartum cardiomyopathy should be considered in women with new-onset palpitations in the last 6 weeks of pregnancy or early postpartum period 3
• Long QT syndrome may be protective during pregnancy due to relative tachycardia but becomes higher risk postpartum when heart rate naturally falls 3

Women

• Drug-induced torsades de pointes occurs more frequently in women than men due to longer baseline QT intervals 3
• Congenital long QT syndrome affects 70% women in registries, with higher event rates post-puberty 3

Elderly

• Ventricular arrhythmias increase in incidence with age, particularly in the presence of structural heart disease 3
• Dosing adjustments for antiarrhythmic drugs are essential due to altered pharmacokinetics 3

Warning Signs Requiring Urgent Evaluation

Palpitations accompanied by any of the following mandate immediate cardiac assessment:

• Syncope or near-syncope suggests hemodynamically significant arrhythmia 3, 1
• Chest pain raises concern for ischemia or life-threatening arrhythmia 3, 1
• Dyspnea may indicate heart failure or hemodynamic compromise 3
• Palpitations during exercise are particularly concerning for ventricular arrhythmias or channelopathies 3, 1
• Family history of sudden cardiac death suggests inherited arrhythmia syndromes 3

Clinical Pattern Recognition

Sudden Onset/Termination Pattern

• Reentrant tachycardias (AVNRT, AVRT) characteristically start and stop abruptly 1
• Termination with vagal maneuvers (Valsalva, carotid massage) suggests AV nodal involvement 1, 8

Gradual Onset/Offset Pattern

• Sinus tachycardia or inappropriate sinus tachycardia typically has gradual changes 1
• Anxiety-related palpitations usually build gradually 4

Irregular Pattern

• Atrial fibrillation causes irregularly irregular palpitations 1
• Frequent PVCs create sensation of skipped beats 1

Unexplained Palpitations

• No identifiable cause is found in up to 16% of patients despite thorough evaluation 2
• These patients generally have good prognosis when structural heart disease and high-risk features are excluded 3
• Continued surveillance may be warranted as some conditions evolve over time 3