What is the best approach to manage a patient presenting with palpitations, considering their medical history, physical examination, and potential underlying cardiac conditions?

Management of Palpitations

Begin with a 12-lead ECG immediately to identify the rhythm and determine if the tachycardia is regular or irregular, as this distinction fundamentally changes your entire diagnostic approach and risk stratification. 1, 2

Initial Clinical Assessment

History must focus on specific pattern characteristics:

• Onset and termination: Sudden onset/offset suggests AVNRT or AVRT, while gradual acceleration indicates sinus tachycardia 1, 2, 3
• Regular vs irregular rhythm: Regular paroxysmal palpitations most commonly indicate AVNRT or AVRT; irregular palpitations suggest atrial fibrillation, premature contractions, or multifocal atrial tachycardia 1, 2, 3
• Response to vagal maneuvers: Termination by Valsalva or carotid massage confirms re-entrant tachycardia involving AV nodal tissue 1, 2, 3
• Associated symptoms: Syncope occurs in approximately 15% of SVT patients and warrants urgent evaluation; polyuria suggests atrial natriuretic peptide release from SVT 1, 3
• Precipitating factors: Identify caffeine, alcohol, nicotine, medications, recreational drugs, exertion, or stressors like infection or volume loss 1, 2

Physical examination priorities:

• Assess for irregular pulse, irregular jugular venous pulsations, and variation in first heart sound intensity 1
• Look for signs of structural heart disease, valvular abnormalities, heart failure, or thyroid dysfunction 1, 4
• Check for irregular cannon A waves and irregular S1 intensity variation during tachycardia, which strongly suggests ventricular origin 2

ECG Interpretation and Risk Stratification

Pre-excitation (delta waves) with paroxysmal regular palpitations indicates AVRT and requires immediate electrophysiology referral due to risk of sudden death. 2, 3, 4 Pre-excitation with irregular palpitations strongly suggests atrial fibrillation with an accessory pathway—this is a medical emergency. 2

Wide complex tachycardia requires immediate specialist referral: Look for AV dissociation or fusion complexes diagnostic of ventricular tachycardia. 2, 3, 4

Ambulatory Monitoring Strategy

Stop all caffeine, alcohol, nicotine, and review medications before initiating monitoring. 2 Instruct patients in Valsalva maneuver and carotid massage to perform during episodes. 2

Monitoring selection based on symptom frequency:

• Daily palpitations: 24-48 hour Holter monitoring 2, 4
• Several times per week: Event or loop recorders have superior diagnostic yield and cost-effectiveness compared to Holter monitoring 2, 4
• Less than twice monthly with severe symptoms: Consider implantable loop recorder 2, 4
• Continue monitoring until symptoms occur while wearing the device—non-diagnostic monitoring is not conclusive 2

Minimum Evaluation Required

All patients require: 1

1. 12-lead ECG to verify rhythm, identify LV hypertrophy, pre-excitation, bundle branch block, prior MI, measure QT interval
2. Thyroid function tests for first episodes, difficult rate control, or unexplained recurrence 1
3. Echocardiography when sustained SVT is documented or clinical suspicion exists for valvular disease, cardiomyopathy, structural abnormalities, or tachycardia-mediated cardiomyopathy 1, 2, 4

Do not order comprehensive laboratory panels routinely—basic labs are only indicated if volume depletion or specific metabolic causes are suspected. 1, 2, 4

Additional Testing Based on Clinical Context

Exercise testing is indicated when: 1, 4

• Palpitations are clearly triggered by exertion
• Adequacy of rate control needs assessment in permanent AF
• Excluding ischemia before initiating type IC antiarrhythmic drugs

Transesophageal echocardiography is reserved for identifying left atrial thrombus or guiding cardioversion in atrial fibrillation. 1

Empiric Medical Therapy

Beta-blockers may be prescribed empirically while awaiting monitoring results, but only after excluding significant bradycardia (<50 bpm). 2, 3

Never start Class I or III antiarrhythmic drugs without documented arrhythmia due to significant proarrhythmic risk. 2, 5 Flecainide causes new or worsened arrhythmias in 4% of supraventricular arrhythmia patients, including fatal ventricular tachycardia/fibrillation. 5

Mandatory Specialist Referral Criteria

Refer immediately to cardiac electrophysiology for: 2, 3, 4

• All patients with Wolff-Parkinson-White syndrome (pre-excitation with arrhythmias)
• Wide complex tachycardia of unknown origin documented on any rhythm strip
• Severe symptoms during palpitations (syncope, presyncope, severe dyspnea)
• Narrow complex tachycardia with drug resistance or intolerance
• Patients desiring freedom from lifelong drug therapy with documented SVT

Catheter ablation has high success rates with <5% recurrence and <1% risk of heart block, offering potential cure rather than lifelong medication. 2

Critical Pitfalls to Avoid

• Do not rely on automatic ECG analysis systems—they are unreliable and commonly suggest incorrect diagnoses 2
• Do not dismiss syncope with palpitations—this occurs in 15% of SVT patients and may indicate very rapid tachycardia, structural abnormalities, or accessory pathways 1, 3
• Do not delay evaluation in patients with structural heart disease—they require echocardiography, prolonged ECG monitoring, and possibly electrophysiological studies 1, 4
• Recognize tachycardia-mediated cardiomyopathy—SVT persisting for weeks to months with fast ventricular response can cause reversible cardiomyopathy 1, 3

Special Populations

Patients with hypertrophic cardiomyopathy and palpitations require 24-48 hour ambulatory monitoring every 1-2 years, with extended monitoring if additional AF risk factors exist (left atrial dilatation, advanced age, NYHA class III-IV). 2, 4