EKG Screening for Psychiatric Medications
EKG screening is not universally required when starting psychiatric medications, but should be obtained for patients with cardiac risk factors or when prescribing medications with known QT-prolonging effects (Class B/B drugs).* 1
Risk-Stratified Approach to EKG Screening
When EKG is NOT Required (Class A Drugs)
- Patients without cardiac risk factors starting low-risk psychiatric medications can begin treatment without baseline EKG. 1
- Low-risk agents include most SSRIs, SNRIs, and benzodiazepines, which have minimal pro-arrhythmic potential. 1
When EKG IS Required
Obtain baseline EKG before starting psychiatric medications if ANY of the following apply:
Patient Risk Factors 1
- Age >50 years (elderly have dramatically increased risk of ischemic heart disease and sudden cardiac death)
- History of cardiac disease (ischemic heart disease, heart failure, structural heart disease, congenital heart disease)
- Cardiac symptoms: chest pain, dyspnea, palpitations, syncope or near-syncope
- Family history of sudden cardiac death or inherited arrhythmia syndromes (long QT syndrome, Brugada syndrome)
- Electrolyte disturbances (hypokalemia, hypomagnesemia)
- Concurrent medications that prolong QT interval or cause drug interactions via CYP inhibition
High-Risk Psychiatric Medications (Class B/B* Drugs) 1
Always obtain baseline EKG when prescribing:
- Tricyclic antidepressants (significant QT prolongation risk) 1
- Phenothiazines (e.g., thioridazine) 1
- Methadone (pronounced QT prolongation, multiple TdP cases reported) 1
- Lithium (can cause bradycardia, T-wave changes, AV block) 1
- Certain atypical antipsychotics with higher arrhythmia risk 2, 3
Follow-Up EKG Monitoring
For patients on Class B/B medications:* 1
- Repeat EKG within 1-2 weeks after starting medication (at steady-state, approximately 5 drug half-lives)
- Repeat EKG after any significant dose increase
- Obtain EKG if new cardiac symptoms develop
Critical EKG Thresholds 1
- QTc >500 msec: Discontinue medication in most cases (definite increased TdP risk)
- QTc increase >60 msec from baseline: Discontinue medication in most cases
- QTc 450-499 msec (males) or 470-499 msec (females): Intermediate risk, consider alternative agent or close monitoring 2
Evidence Quality and Nuances
The European Heart Journal guidelines 1 provide the most comprehensive risk-stratified approach, emphasizing that psychiatric patients have higher baseline cardiovascular disease prevalence due to lifestyle factors, poor treatment compliance, and possible shared genetic factors. 1
The ACC/AHA guidelines 1 classify EKG monitoring for psychotropic agents as Class I indication when prescribed therapy may produce adverse effects detectable by EKG changes, supporting selective rather than universal screening.
Important caveat: Research evidence 4, 3 demonstrates that routine screening EKGs in low-risk psychiatric patients yield few clinically significant abnormalities, with one study showing only 0.14% management changes in 691 patients. 5 However, abnormalities are frequent enough in patients >50 years to merit routine screening in this age group. 4
Common Pitfalls to Avoid
- Don't skip baseline EKG in elderly patients (>50 years), even for "low-risk" medications—this population has 10-fold higher sudden cardiac death rates. 1
- Don't assume all antipsychotics carry equal risk—they vary significantly in QT-prolonging effects. 2, 3
- Don't forget to assess concurrent medications for drug interactions and additive QT prolongation (diuretics causing hypokalemia, CYP inhibitors, other QT-prolonging drugs). 1
- Don't rely solely on continuous rhythm monitoring—a full 12-lead EKG provides more diagnostic information for QT assessment. 1
Special Populations
Methadone maintenance programs: Baseline EKG recommended for all patients with risk factors, annually, and when daily dose exceeds 100-120 mg. 1
Children/adolescents: Routine screening not indicated unless cardiac risk factors present or using medications with established cardiac effects. 5