What EKG (electrocardiogram) findings should be cautiously considered prior to initiating a psychostimulant, such as methylphenidate (Ritalin) or amphetamines?

EKG Findings Requiring Caution Before Starting Psychostimulants

Obtain cardiology consultation before initiating psychostimulants if the EKG shows QTc prolongation (>450 ms in men, >460 ms in women), conduction abnormalities (bundle branch blocks, AV blocks, accessory pathways), evidence of ischemic heart disease (pathologic Q waves, ST-segment changes, T-wave inversions), or ventricular hypertrophy patterns. 1

High-Risk EKG Abnormalities Requiring Cardiology Evaluation

QTc Prolongation

• QTc >450 ms in men or >460 ms in women represents a contraindication to starting stimulants without cardiology clearance, as this increases risk of torsade de pointes and sudden cardiac death, particularly when combined with stimulant-induced tachycardia. 1
• This concern is especially relevant given that stimulants predictably increase heart rate by 3-6 bpm on average, which can further prolong the QT interval in susceptible patients. 1

Conduction Abnormalities

• Any bundle branch block (right or left), AV blocks (first-degree or higher), or evidence of accessory pathways (such as Wolff-Parkinson-White pattern) mandate cardiology consultation before stimulant initiation. 1
• The FDA explicitly warns against using stimulants in patients with serious cardiac arrhythmias. 2, 3

Ischemic Changes

• Pathologic Q waves, ST-segment abnormalities, or T-wave inversions in contiguous leads suggest underlying ischemic heart disease and require cardiac evaluation before stimulant therapy. 1
• This is critical because sudden deaths, stroke, and myocardial infarction have been reported in adults taking stimulants at usual ADHD doses. 3

Ventricular Hypertrophy

• Left or right ventricular hypertrophy patterns indicate underlying cardiomyopathy or chronic hypertension that increases sudden cardiac death risk. 1
• The FDA specifically contraindicates stimulant use in patients with known cardiomyopathy. 2, 3

When to Obtain Baseline EKG

A baseline EKG should be obtained in patients with cardiac disease history, cardiac symptoms (chest pain, syncope, palpitations), family history of sudden cardiac death or inherited arrhythmia syndromes (long QT, hypertrophic cardiomyopathy), age >50 years, or concomitant use of QT-prolonging medications or CYP inhibitors. 1

• The FDA mandates that patients being considered for stimulant treatment should have careful history (including family history of sudden death or ventricular arrhythmia) and physical exam, with further cardiac evaluation including ECG if findings suggest cardiac disease. 3
• Routine ECGs in all patients are not evidence-based and create unnecessary healthcare costs—risk-stratified screening based on patient factors is the appropriate approach. 1

Expected Cardiovascular Changes During Treatment

• Stimulants cause predictable increases in heart rate (mean 3-6 bpm) and blood pressure (mean 2-4 mmHg systolic and diastolic). 1, 2, 3
• However, 5-15% of patients may experience substantially larger increases requiring monitoring. 1, 4

Critical Pitfalls to Avoid

• Never skip baseline EKG in elderly patients (>50 years), even for "low-risk" medications, as sudden cardiac death rates increase 10-fold in this population. 1
• Do not use stimulants in patients with known structural cardiac abnormalities, cardiomyopathy, serious cardiac arrhythmias, coronary artery disease, or other serious cardiac disease without cardiology clearance. 2, 3
• Occasional supraventricular premature beats in asymptomatic patients without structural heart disease do not contraindicate stimulant therapy, but symptomatic arrhythmias (syncope, presyncope during palpitations) require cardiology evaluation. 4
• Patients who develop exertional chest pain, unexplained syncope, or other cardiac symptoms during stimulant treatment require prompt cardiac evaluation including ECG. 3