What are palpitations?

What Are Palpitations?

Palpitations are an unpleasant awareness of the heartbeat, described by patients as sensations of pounding, racing, skipped beats, pauses, or feeling the heart beat in the chest, throat, or neck. 1

Core Clinical Descriptions

Patients typically report palpitations using one of these patterns:

• Heartbeat sensations that feel like pounding or racing – the most common description of sustained tachyarrhythmias 1
• An unpleasant awareness of heartbeat – can occur even with normal sinus rhythm when patients become hyperaware of their cardiac activity 1, 2
• Feeling skipped beats or a pause – classic description of premature beats (atrial or ventricular), where the compensatory pause after an ectopic beat is followed by a forceful contraction 1, 3
• Irregularities in heart rhythm – suggests atrial fibrillation, multifocal atrial tachycardia, or frequent premature contractions 1, 3

Pathophysiological Mechanisms

The neural pathways responsible for perceiving heartbeat involve both intracardiac and extracardiac structures, though these remain incompletely understood. 2 Palpitations arise from three fundamental cardiac mechanisms:

• Automaticity – enhanced or abnormal pacemaker activity in cardiac cells that can create ectopic foci 3
• Triggered activity – disturbances in repolarization causing afterdepolarizations that reach threshold and trigger premature beats 1, 3
• Re-entry – the most common arrhythmia mechanism, involving repetitive excitation around a circuit (fixed or functional), responsible for most sustained tachycardias like AVNRT and AVRT 1, 3

Clinical Significance and Risk Stratification

The critical distinction is whether palpitations represent a benign awareness of normal cardiac activity versus a manifestation of potentially dangerous arrhythmia. 4, 5 This distinction fundamentally determines the urgency and extent of evaluation.

High-Risk Features Requiring Urgent Evaluation

• Syncope or presyncope accompanying palpitations – suggests hemodynamically significant arrhythmia or structural heart disease 1, 6, 7
• Chest pain or dyspnea during episodes – may indicate ischemia, heart failure, or severe tachyarrhythmia 1, 6, 7
• Palpitations occurring during exertion – particularly concerning in patients with structural heart disease (hypertrophic cardiomyopathy, aortic stenosis, coronary disease) 6, 7
• Family history of sudden cardiac death – mandates screening for inherited arrhythmia syndromes (long QT, Brugada, hypertrophic cardiomyopathy) 6, 7
• Wide-complex tachycardia documented on any rhythm strip – may represent ventricular tachycardia requiring immediate evaluation 6

Pattern Recognition for Diagnosis

Regular versus irregular rhythm is the single most important distinguishing feature. 6

Regular palpitations with sudden onset and sudden termination (paroxysmal):

• Most commonly indicate AVNRT or AVRT – re-entrant tachycardias involving AV nodal tissue 1, 6, 3
• Termination by vagal maneuvers (Valsalva, carotid massage) strongly supports this diagnosis 1, 6
• Approximately 15% of SVT patients experience polyuria due to atrial natriuretic peptide release from atrial contraction against closed AV valves 1, 6

Regular palpitations with gradual onset and offset:

• Suggests sinus tachycardia triggered by physiologic stressors (infection, volume loss, fever, anemia) or substances (caffeine, nicotine, stimulants) 1, 6

Irregular palpitations:

• May represent atrial fibrillation, multifocal atrial tachycardia (especially in pulmonary disease), or frequent premature contractions 1, 3

Common Etiologies

Cardiac Arrhythmic Causes

• Premature contractions (atrial or ventricular) – benign in structurally normal hearts, but very frequent PVCs (>10,000-20,000/day) can cause reversible cardiomyopathy 3
• Supraventricular tachycardias – AVNRT, AVRT, atrial flutter, atrial fibrillation 1, 3
• Ventricular arrhythmias – ventricular tachycardia, particularly concerning in structural heart disease 1, 3

Non-Arrhythmic Cardiac Causes

• Structural heart disease – hypertrophic cardiomyopathy, valvular disease (especially mitral valve prolapse), heart failure 1, 8
• Wolff-Parkinson-White syndrome – pre-excitation carries risk of sudden death and requires immediate electrophysiology referral 6

Non-Cardiac Causes

• Hyperthyroidism – a common and treatable cause that must be excluded with thyroid function tests 6, 8
• Psychiatric conditions – anxiety-induced sinus tachycardia is common, though anxiety also frequently coexists with true cardiac arrhythmias 2, 9, 8
• Medications and substances – caffeine, nicotine, alcohol, stimulants (cocaine, amphetamines), QT-prolonging drugs, anticholinergics, over-the-counter supplements 6, 4, 8
• Metabolic disturbances – hypoglycemia, electrolyte abnormalities, dehydration 6, 8

Critical Clinical Pitfalls

• Many patients with serious arrhythmias do not experience palpitations – they may instead present with syncope, shock, chest pain, or sudden death 4
• Conversely, up to 16% of patients with palpitations have no identifiable cause after thorough evaluation, and most have benign outcomes 8
• Anxiety is common in patients with true cardiac arrhythmias – do not dismiss palpitations as purely psychiatric without objective rhythm documentation 9
• Normal palpitations occur physiologically with exercise, emotions, stress, or after substances that increase adrenergic tone, but some patients find even normal sinus tachycardia troublesome enough to seek care 4