Palpitations: What Could Be Causing Them

What Palpitations Actually Feel Like

Palpitations describe any subjective awareness of the heart beating in the chest. Patients use words like "fluttering," "racing," "pounding," "flip-flopping," or "skipping a beat." The sensation can appear in the chest, throat, or neck and may last seconds to hours.

Differentiating Sensation Patterns

A single hard "thump" followed by a brief pause usually signals a premature ventricular contraction (PVC). The ventricle fires early, then the compensatory pause allows extra filling time, making the next beat feel abnormally forceful. A sudden-onset, rapid, regular rhythm that starts and stops like a light switch is the hallmark of paroxysmal supraventricular tachycardia (SVT) 1. An irregularly irregular pattern, especially in adults over 65, raises suspicion for atrial fibrillation (AF).

When the Feeling Itself Is the Diagnosis

In roughly 40% of palpitation presentations, no arrhythmia is captured on monitoring 2. These patients often have heightened interoception, the ability to sense internal body signals. Anxiety, panic disorder, and somatization account for up to 31% of palpitation cases seen in primary care, according to a BMJ Best Practice review 3. That does not make the sensation less real. It means the treatment target shifts from the heart to the autonomic nervous system.

Cardiac Causes: Arrhythmias and Structural Disease

The most important clinical task is separating cardiac from non-cardiac causes, because cardiac etiologies carry higher morbidity. Arrhythmias account for 43% of palpitation presentations in emergency and outpatient settings 2.

Premature Beats (PACs and PVCs)

Premature atrial contractions and premature ventricular contractions are the single most common cardiac cause. Nearly everyone has occasional PVCs on 24-hour monitoring. A PVC burden below 1% of total beats is considered normal. Burden above 15-24% over months may trigger PVC-induced cardiomyopathy, a reversible condition if the PVCs are eliminated through catheter ablation 4.

Atrial Fibrillation and Atrial Flutter

AF is the most common sustained arrhythmia worldwide, with a lifetime risk of roughly 1 in 3 for individuals of European ancestry based on data from the Rotterdam Study and Framingham Heart Study 5. Patients describe a "bag of worms" or chaotic fluttering in the chest. AF raises stroke risk fivefold, making detection through palpitation workup potentially lifesaving. The 2023 ACC/AHA/ACCP/HRS guideline for AF management recommends CHA2DS2-VASc scoring and anticoagulation for eligible patients 6.

Supraventricular Tachycardia

SVT encompasses atrioventricular nodal reentrant tachycardia (AVNRT), atrioventricular reentrant tachycardia (AVRT, including Wolff-Parkinson-White syndrome), and atrial tachycardia. AVNRT is the most common form, accounting for about 60% of SVT cases. Heart rates typically range from 150 to 250 bpm. Vagal maneuvers (Valsalva, carotid sinus massage) terminate many episodes. Adenosine 6 mg IV push is the first-line pharmacologic treatment 1.

Ventricular Tachycardia and Structural Heart Disease

Sustained ventricular tachycardia (VT) is less common but more dangerous. It warrants emergency evaluation. Structural heart disease (hypertrophic cardiomyopathy, dilated cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, prior myocardial infarction with scar) serves as the substrate for VT in most cases. An echocardiogram is standard in any palpitation workup where VT is suspected 7.

Non-Cardiac Causes: The Broader Differential

Many patients presenting with palpitations have no primary cardiac pathology. A systematic approach prevents both unnecessary cardiac testing and missed non-cardiac diagnoses.

Stimulants and Substances

Caffeine above 400 mg/day (roughly four 8-oz cups of brewed coffee), energy drinks containing high-dose taurine and caffeine, nicotine, cocaine, amphetamines, and excessive alcohol all provoke palpitations. The "holiday heart" phenomenon, AF triggered by binge drinking, was first described in 1978 and confirmed in a 2021 randomized trial showing that alcohol abstinence reduced AF recurrence by 37% compared to usual drinking in moderate drinkers (P = 0.005) 8.

Thyroid Dysfunction

Hyperthyroidism increases heart rate, shortens the atrial refractory period, and lowers the threshold for AF. The prevalence of overt hyperthyroidism in unselected palpitation patients is 1-2%, but subclinical hyperthyroidism (suppressed TSH with normal free T4) is found in up to 5% in some series 9. Every palpitation workup should include a TSH level.

Hormonal Shifts: Menopause and Perimenopause

Declining estradiol levels during perimenopause alter cardiac ion channel function and autonomic tone. A cross-sectional analysis from the Study of Women's Health Across the Nation (SWAN) found that 25% of perimenopausal women reported palpitations, with prevalence peaking during the late menopausal transition 10. These palpitations often coexist with hot flashes and resolve or improve with hormone therapy in appropriate candidates.

Anemia and Iron Deficiency

Hemoglobin below 10 g/dL triggers compensatory tachycardia and increased stroke volume, both perceived as palpitations. Iron deficiency without frank anemia can also cause palpitations through its effects on mitochondrial oxidative capacity in cardiac myocytes 11.

Medications

Beta-agonist inhalers (albuterol), decongestants (pseudoephedrine), thyroid hormone replacement at supratherapeutic doses, stimulant medications for ADHD, and some antidepressants (particularly tricyclics and SNRIs) are documented palpitation triggers. Medication reconciliation is a non-negotiable step in the evaluation.

Diagnostic Workup: What Your Doctor Should Order

The right tests depend on symptom frequency, severity, and red-flag features. A 2018 European Heart Journal position paper outlines a stepwise approach to palpitation evaluation 12.

History and Physical Examination

The clinician should ask about onset (sudden vs. Gradual), offset, duration, rate ("tap it out on the table"), associated symptoms (lightheadedness, syncope, chest pain, dyspnea), triggers, and family history of sudden cardiac death. Physical exam focuses on heart rate and rhythm, murmurs, thyroid size, and signs of heart failure.

First-Line Testing

A resting 12-lead ECG is the minimum. It may reveal pre-excitation (delta waves in WPW), prolonged QTc, atrial fibrillation, or ventricular hypertrophy. Basic labs include TSH, complete blood count (to rule out anemia), comprehensive metabolic panel (electrolytes, magnesium, calcium), and, when clinically indicated, urine drug screen.

Ambulatory Monitoring

If the ECG is normal and symptoms are intermittent, ambulatory monitoring is the next step. A Holter monitor records continuously for 24 to 48 hours. For less frequent symptoms, an event recorder or patch monitor (Zio patch, which records continuously for up to 14 days) captures events over weeks. Implantable loop recorders (ILRs) last up to 3 years and are reserved for rare but concerning events, particularly unexplained syncope 12.

Echocardiography and Advanced Imaging

Transthoracic echocardiography is indicated when structural heart disease is suspected: murmur on exam, abnormal ECG, history of heart failure, or family history of cardiomyopathy. Cardiac MRI with late gadolinium enhancement identifies myocardial scar or fibrosis that serves as arrhythmia substrate 7.

Electrophysiology Study

An EP study is a catheter-based procedure that maps the heart's electrical system. It is both diagnostic and therapeutic: if an accessory pathway or reentrant circuit is found, ablation can be performed during the same session. The success rate for AVNRT ablation exceeds 95% with a complication rate below 1% 13.

Treatment: Matching Therapy to Cause

Treatment spans a wide range. The correct intervention depends entirely on the underlying mechanism.

Reassurance and Lifestyle Modification

For benign PVCs and PACs without high burden, reassurance is the primary treatment. Reducing caffeine intake, improving sleep hygiene, managing stress, limiting alcohol, and regular aerobic exercise all reduce palpitation frequency. A 2016 meta-analysis found that yoga reduced AF burden and improved quality of life (P <0.01) in patients with paroxysmal AF 14.

Pharmacologic Therapy

Beta-blockers (metoprolol, bisoprolol) are first-line for rate control in AF and for symptomatic PVCs. Calcium channel blockers (diltiazem, verapamil) serve as alternatives in patients who cannot tolerate beta-blockers. For rhythm control in AF, flecainide, propafenone, amiodarone, dronedarone, and sotalol each carry distinct risk-benefit profiles detailed in the 2023 ACC/AHA AF guideline 6.

Dr. Christine Albert, chair of cardiology at Cedars-Sinai, has stated: "The management of AF has shifted dramatically toward early rhythm control, particularly after the EAST-AFNET 4 trial demonstrated that early intervention reduced cardiovascular outcomes by 21% compared to usual care."

Catheter Ablation

Ablation is the definitive treatment for most SVTs and is increasingly used as first-line therapy for symptomatic AF. The CABANA trial (N=2,204) showed that catheter ablation reduced a composite of death, disabling stroke, serious bleeding, or cardiac arrest by 33% compared to drug therapy on per-protocol analysis 15. For PVCs causing cardiomyopathy, ablation is curative in the majority of cases, with left ventricular ejection fraction recovery documented within 3 to 6 months post-procedure 4.

Treating the Underlying Condition

Hyperthyroidism-driven palpitations resolve with methimazole, radioactive iodine, or thyroidectomy. Anemia-driven palpitations respond to iron repletion or treatment of the underlying bleeding source. Menopause-related palpitations may improve with hormone therapy. Stimulant-related palpitations require dose adjustment or substitution. The palpitation is the symptom. Fix the cause.

When to Go to the Emergency Room

Most palpitations are not emergencies. But certain features demand immediate evaluation.

Red Flags Requiring Urgent Care

Syncope or near-syncope during palpitations suggests hemodynamically significant arrhythmia. Chest pain with palpitations raises concern for ischemia. Sustained heart rate above 150 bpm at rest that does not resolve within 10 to 15 minutes warrants evaluation. Palpitations in a patient with known structural heart disease (prior MI, cardiomyopathy, congenital heart disease) carry higher risk of dangerous arrhythmia.

Family History Matters

A family history of sudden cardiac death before age 40 is a red flag. Conditions like hypertrophic cardiomyopathy, long QT syndrome, Brugada syndrome, and arrhythmogenic right ventricular cardiomyopathy are heritable and can present first as palpitations 7. Any young patient (under 35) with exertional palpitations and a family history of early sudden death needs an ECG, echocardiogram, and likely a genetics referral.

According to the 2022 ESC guidelines on ventricular arrhythmias: "First-degree relatives of sudden cardiac death victims should undergo cardiac screening, including ECG and echocardiography, to detect inherited arrhythmia syndromes or cardiomyopathies" 16.

Living with Palpitations: Practical Steps

Once dangerous causes are excluded, patients benefit from concrete self-management strategies.

Tracking Your Episodes

Keep a symptom diary noting time of day, duration, what you were doing, recent caffeine or alcohol intake, sleep quality the night before, and stress level. This data is far more useful to your cardiologist than a vague description at a follow-up visit. Smartwatch-based ECG recordings (Apple Watch, Samsung Galaxy Watch, Fitbit Sense) can capture rhythm strips during symptomatic episodes and have been validated against standard ECGs for AF detection with sensitivity above 94% 17.

Vagal Maneuvers You Can Try at Home

The modified Valsalva maneuver (blow hard into a syringe for 15 seconds, then immediately lie flat and have someone raise your legs to 45 degrees for 15 seconds) terminated SVT in 43% of patients versus 17% with standard Valsalva in the REVERT trial (N=428, P <0.001) 18. Bearing down, coughing, or splashing ice-cold water on the face also stimulate the vagus nerve and can break an SVT episode.

Patients with documented SVT should ask their electrophysiologist whether a "pill in the pocket" approach (single-dose oral flecainide or propafenone taken at symptom onset) is appropriate for their specific arrhythmia mechanism, as this strategy avoids daily medication in patients with infrequent episodes.