Feeling your heart flutter, pound, skip a beat, or race unexpectedly is alarming — even when the cause is entirely benign. Heart palpitations are the sensation of an abnormal heartbeat, and they send millions of Americans to urgent care and emergency rooms each year. The good news: the vast majority of palpitations are harmless. The important skill is recognising the minority that signal a problem requiring prompt attention.
What Do Palpitations Feel Like?
People describe palpitations in many ways: a flip-flop or fish-flopping sensation in the chest, a thud followed by a pause, a racing or pounding heartbeat, or a fluttering like butterfly wings. They may occur in the chest, throat, or neck, last seconds to minutes, and come and go unpredictably. They can occur at rest, during exertion, or when lying down at night.
Common Benign Causes
- Ectopic beats (PACs and PVCs): Premature atrial or ventricular contractions are extra beats originating outside the heart's normal pacemaker. They cause the characteristic "skipped beat" sensation followed by a stronger-than-normal beat. They are almost universal — most people have them; most are unaware. Occasional ectopic beats in a structurally normal heart require no treatment.
- Caffeine: Coffee, tea, energy drinks, and some medications stimulate the sympathetic nervous system, increasing heart rate and ectopic beat frequency.
- Stress and anxiety: Adrenaline release during anxiety states causes rapid heart rate, forceful beats, and heightened awareness of the heartbeat.
- Dehydration and electrolyte imbalance: Low potassium or magnesium directly increases cardiac excitability and ectopic beat frequency.
- Alcohol: Even moderate alcohol consumption can trigger atrial fibrillation in susceptible individuals — the "holiday heart" phenomenon.
- Strenuous exercise: Post-exercise palpitations are common and almost always benign.
Causes That Require Medical Attention
Atrial Fibrillation (AFib)
AFib is the most common sustained cardiac arrhythmia, affecting over 33 million people worldwide. Palpitations from AFib are typically felt as an irregular, chaotic heartbeat lasting minutes to hours. AFib markedly increases stroke risk by allowing blood to pool and clot in the left atrial appendage — anticoagulation therapy reduces this risk by approximately 65%. If you experience a rapid, irregular heartbeat lasting more than a few minutes, seek immediate evaluation.
Supraventricular Tachycardia (SVT)
SVT produces sudden-onset, rapid regular palpitations (150–250 beats per minute) that stop as abruptly as they start. Most episodes are not life-threatening but are highly symptomatic. Vagal manoeuvres (bearing down, cold water on the face) sometimes terminate episodes. Radiofrequency catheter ablation is curative in the majority of cases.
Ventricular Tachycardia (VT)
VT originates in the ventricles and can degenerate into ventricular fibrillation and sudden cardiac death. It typically occurs in the context of structural heart disease. Palpitations accompanied by syncope (fainting), near-syncope, or chest pain require immediate emergency evaluation.
Thyroid Disorders
Both hyperthyroidism and thyroid hormone excess from over-treated hypothyroidism produce palpitations, anxiety, heat intolerance, and tremor. A TSH blood test rapidly identifies this reversible cause.
When to Call Emergency Services Immediately
Call 911 if palpitations are accompanied by: chest pain or pressure, severe shortness of breath, fainting or near-fainting, one-sided weakness or face drooping (stroke), or if they occur in someone with known heart disease or a family history of sudden cardiac death.
Diagnosis
Evaluation begins with a 12-lead ECG, which captures rhythm during palpitations if the patient is symptomatic at the time of evaluation. A Holter monitor (24–48 hour continuous ECG recording) or event monitor (worn up to 30 days) captures sporadic arrhythmias. Echocardiography assesses cardiac structure and function. Blood work including thyroid function, electrolytes, and a metabolic panel addresses secondary causes.
Sources
- Hindricks G, et al. 2020 ESC Guidelines for AFib. Eur Heart J. 2021.
- American Heart Association. Palpitations. 2023.
- Mayo Clinic. Heart palpitations — Causes. 2023.
- Zimetbaum P. Evaluation of Palpitations in Adults. UpToDate. 2023.