What is the appropriate workup for a patient presenting with palpitations?

Workup for Palpitations

Obtain a 12-lead ECG immediately to document the rhythm, identify pre-excitation patterns, and determine whether the tachycardia is regular or irregular—this single distinction fundamentally changes your entire diagnostic approach and risk stratification. 1

Immediate Clinical Assessment

Critical History Elements

• Characterize the rhythm pattern: Ask specifically whether palpitations feel regular or irregular, as this is the most important diagnostic factor 1
• Onset and termination: Sudden onset with sudden termination strongly suggests AVNRT or AVRT, particularly in younger patients 1, 2
• Response to vagal maneuvers: Termination with Valsalva or carotid massage confirms re-entrant tachycardia involving AV nodal tissue 1, 2
• Frequency and duration: Document number of episodes, how long each lasts, and how often they occur 3, 1
• Precipitating factors: Specifically inquire about alcohol, caffeine, sleep deprivation, emotional stress, exercise, and large meals—patients often don't volunteer this information 3
• Associated symptoms: Ask about syncope, presyncope, chest pain, dyspnea, and polyuria (occurs in ~15% of SVT patients) 3, 1, 2

Physical Examination Findings

• Irregular pulse and jugular venous pulsations suggest atrial fibrillation 3
• Variation in first heart sound intensity or absence of a previously heard fourth heart sound indicates AF 3
• Irregular cannon A waves during tachycardia strongly suggest ventricular origin 1
• Examine for valvular disease, heart failure, and structural abnormalities 3

Mandatory Initial Testing

All Patients Require:

• 12-lead ECG: Look for pre-excitation (delta waves), conduction abnormalities, and baseline rhythm 3, 1
• Thyroid function tests: Hyperthyroidism causes 5-15% of AF cases, especially in patients over 60 1
• Complete blood count, electrolytes (especially potassium), renal function, and hepatic function 3, 1
• Chest radiograph: Evaluate for pulmonary pathology and pulmonary vasculature 3

Echocardiography Indications:

• All patients with documented sustained SVT to exclude structural heart disease that physical examination alone cannot detect 1
• Clinical suspicion of valvular aortic stenosis, hypertrophic cardiomyopathy, or tachycardia-mediated cardiomyopathy 1
• Any patient with AF to assess left atrial and ventricular dimensions, wall thickness, function, and exclude valvular or pericardial disease 3

Rhythm Documentation Strategy

For Daily Palpitations:

• 24-48 hour Holter monitoring is the appropriate choice 1

For Weekly Palpitations:

• Event or loop recorders have superior diagnostic yield and are more cost-effective than Holter monitoring 1

For Infrequent Episodes (<2 per month):

• Implantable loop recorder if symptoms are severe or associated with hemodynamic instability 1

Critical Monitoring Principles:

• Stop all caffeine, alcohol, and nicotine before monitoring 1
• Teach patients Valsalva maneuver and carotid massage to perform during episodes 1
• Continue monitoring until symptoms occur while wearing the device—non-diagnostic monitoring is not conclusive 1
• Do not rely on automatic ECG interpretation systems; they are unreliable and frequently suggest incorrect diagnoses 1

Immediate Specialist Referral Required For:

• All patients with Wolff-Parkinson-White syndrome (pre-excitation with arrhythmias) due to risk of sudden death 1, 2
• Wide complex tachycardia documented on any rhythm strip 1
• Syncope or severe presyncope during palpitations 1, 2
• Pre-excitation with irregular palpitations (suggests AF with accessory pathway) 1
• Drug-resistant or drug-intolerant narrow complex tachycardia 1

Empiric Medical Therapy Considerations

• Beta-blockers may be prescribed empirically while awaiting monitoring results, but only after excluding significant bradycardia (<50 bpm) 1
• Never start Class I or III antiarrhythmic drugs without documented arrhythmia due to significant proarrhythmic risk 1

High-Risk Features Requiring Urgent Evaluation

• Syncope or presyncope with palpitations 1
• Chest pain or dyspnea during episodes 1
• Palpitations occurring with exertion in patients with known structural heart disease 1
• Family history of sudden cardiac death (screen first-degree relatives) 1

Special Populations

Hypertrophic Cardiomyopathy:

• 24-48 hour ambulatory monitoring every 1-2 years as part of routine follow-up 1
• Extended monitoring if additional AF risk factors present (left atrial dilatation, advanced age, NYHA class III-IV) 1

Hyperthyroidism:

• Beta-blockers are the preferred initial agent for rate control 1
• Most thyrotoxicosis-induced arrhythmias spontaneously convert to sinus rhythm once euthyroid 1
• Assess stroke risk with CHA₂DS₂-VASc score if AF is documented 1
• Never abruptly withdraw beta-blockers once started, as this can precipitate thyroid storm 1

Common Pitfalls to Avoid

• Starting antiarrhythmics empirically without documented arrhythmia 1
• Ordering comprehensive laboratory panels routinely beyond the mandatory tests listed above 1
• Dismissing syncope that occurs with palpitations—this is a high-risk feature 1
• Relying on automatic ECG interpretation 1