What is the appropriate workup for an adult patient with no significant past medical history presenting with heart palpitations?

Heart Palpitations Workup

All adults presenting with heart palpitations require a 12-lead ECG as the essential initial diagnostic test, combined with detailed symptom characterization and targeted history to identify potentially life-threatening arrhythmias versus benign causes. 1, 2, 3

Initial Clinical Assessment

Critical Symptom Characterization

• Document frequency, duration, onset/offset patterns (abrupt onset/termination suggests AVRT or AVNRT, while gradual onset suggests sinus tachycardia) 1
• Determine if palpitations are regular or irregular, as irregular patterns may indicate premature depolarizations, atrial fibrillation, or multifocal atrial tachycardia 1
• Assess for associated red flag symptoms: syncope, pre-syncope, chest pain, dyspnea, or dizziness—these warrant immediate cardiology referral 1, 2
• Identify precipitating factors including caffeine, alcohol, exercise, stress, or medications 1
• Note timing patterns: nocturnal episodes suggest vagally-mediated arrhythmias, while daytime activity-related episodes indicate adrenergically-mediated arrhythmias 1

Physical Examination Priorities

• Evaluate for signs of hemodynamic instability including hypotension, altered mental status, or signs of shock 4
• Assess for congestive heart failure findings (elevated jugular venous pressure, pulmonary rales, peripheral edema), as these patients are at higher risk of adverse outcomes 4
• Examine for cardiac outflow obstruction (murmurs suggesting aortic stenosis or hypertrophic cardiomyopathy), which increases risk 4

Mandatory Diagnostic Testing

12-Lead ECG (Required for All Patients)

• Obtain immediately to document arrhythmia and identify baseline abnormalities including conduction delays, pre-excitation patterns, QT prolongation, or evidence of structural heart disease 1, 2, 3
• An abnormal ECG (any rhythm/conduction abnormality, ventricular hypertrophy, or prior MI evidence) is a multivariate predictor for arrhythmia or death within 1 year 4
• Normal ECG indicates low likelihood of dysrhythmias as the cause 4

Laboratory Testing

• Complete blood count to evaluate for anemia as a cause of compensatory tachycardia 1
• Comprehensive metabolic panel to assess electrolytes (particularly potassium, magnesium, calcium), renal function, and glucose 1
• Thyroid function tests (TSH) to exclude hyperthyroidism 1
• Pregnancy test in women of childbearing potential, though pregnancy should not dissuade evaluation for other risk factors 4

Common Pitfall: Routine blood tests are frequently ordered but rarely yield diagnostic information beyond the specific tests listed above 4

Ambulatory Rhythm Monitoring Strategy

When Initial ECG Doesn't Capture the Arrhythmia

• 24-48 hour Holter monitor for patients with daily or frequent episodes 1, 2
• Event recorder or mobile cardiac telemetry for less frequent episodes (preferred over Holter for intermittent symptoms) 1, 2, 3
• Two-week continuous closed-loop event recording is indicated when palpitations occur unpredictably or not daily 2
• Monitoring beyond 24 hours rarely increases yield unless specific risk factors present (age >65, male sex, history of heart disease, nonsinus rhythm on initial ECG) 4

Common Pitfall: Trans-telephonic event monitors are more effective and cost-effective than Holter monitors for most patients with intermittent symptoms 2

Risk Stratification for Admission Decision

High-Risk Features Requiring Admission or Urgent Cardiology Referral

• History of ventricular arrhythmias 4
• Abnormal ECG (as defined above) 4
• Age >45 years 4
• History of congestive heart failure 4
• Palpitations associated with syncope, pre-syncope, or chest pain 1
• Heart rate >150 bpm with symptoms of instability (acute altered mental status, ischemic chest discomfort, acute heart failure, hypotension, or shock) 4

When Tachycardia is Likely Secondary (Not Primary Cause)

• Heart rate <150 bpm in absence of ventricular dysfunction suggests tachycardia is secondary to underlying condition rather than the cause of instability 4
• Sinus tachycardia (rate >100 bpm but within age-predicted maximum of 220 minus age) requires identification and treatment of underlying cause, not specific drug treatment 4

Critical Consideration: When cardiac function is poor, cardiac output can be dependent on rapid heart rate—"normalizing" the heart rate can be detrimental in compensatory tachycardias 4

Additional Evaluation Based on Initial Findings

Echocardiography Indications

• Recommended when structural heart disease is suspected based on history, physical examination, or ECG findings 4
• Required for high-risk patients including those with dilated, hypertrophic, or RV cardiomyopathies, acute MI survivors, or relatives of patients with inherited disorders associated with sudden cardiac death 4

Exercise Testing Indications

• Patients with intermediate or greater probability of coronary heart disease by age, gender, and symptoms to provoke ischemic changes or ventricular arrhythmias 4
• Known or suspected exercise-induced ventricular arrhythmias including catecholaminergic VT 4
• Evaluating response to medical or ablation therapy in patients with known arrhythmias 4

Electrophysiology Consultation Criteria

• Immediate referral if palpitations associated with syncope, pre-syncope, or chest pain 1
• Consider consultation if initial workup suggests specific arrhythmia or symptoms significantly impact quality of life despite negative initial evaluation 1
• Patients with supraventricular tachycardia, long QT syndrome, or ventricular tachycardia should be referred to cardiology 3

Special Population Considerations

Elderly Patients

• Complex ventricular ectopy is common in patients >60 years and should not be dismissed as benign without appropriate evaluation 1
• Adjust dosing and titration of any antiarrhythmic drugs to account for altered pharmacokinetics 1
• Sudden cardiac death incidence increases with advancing age, and complex ventricular arrhythmias often presage new major coronary events in patients with coronary heart disease 1

Critical Pitfall: Failing to distinguish between ventricular tachycardia and supraventricular tachycardia with aberrancy can lead to inappropriate and potentially dangerous treatment 1