Should an Abnormal EKG Delay Surgery?
An abnormal preoperative EKG should not automatically delay surgery—the decision depends on whether the abnormality represents an active cardiac condition requiring treatment, the surgical risk level, and the patient's functional capacity. 1
Active Cardiac Conditions That MUST Delay Surgery
Surgery should be postponed if the EKG reveals any of these active cardiac conditions that require evaluation and treatment first 1:
- Acute ST-segment changes indicating myocardial ischemia or infarction 2
- Unstable or severe arrhythmias (e.g., symptomatic ventricular arrhythmias, high-grade AV block, symptomatic bradycardia, newly recognized ventricular tachycardia) 1
- Acute decompensated heart failure (if clinical correlation supports this) 1
These patients require immediate cardiology evaluation and treatment per ACC/AHA guidelines before proceeding with elective noncardiac surgery 1.
EKG Abnormalities That Generally Do NOT Require Delay
Most chronic EKG abnormalities found on preoperative screening do not independently predict perioperative cardiac complications and should not delay surgery 3:
- Chronic Q waves (indicating old MI) without symptoms—warrant echocardiography to assess LV function but don't automatically delay surgery 4
- Bundle branch blocks (LBBB, RBBB) in asymptomatic patients 1, 2
- Left ventricular hypertrophy with strain pattern 1
- Nonspecific ST-T wave changes without acute ischemic pattern 2
- Isolated premature ventricular contractions or asymptomatic nonsustained ventricular tachycardia 1
A key study of 513 geriatric surgical patients found that preoperative EKG abnormalities (present in 75% of patients) did not predict postoperative cardiac complications after controlling for clinical factors 3. The strongest predictors were ASA class ≥3 and history of heart failure, not EKG findings 3.
Risk-Stratified Decision Algorithm
For Low-Risk Surgery
- Proceed regardless of EKG findings in asymptomatic patients 1, 5
- Routine preoperative EKG is Class III (not recommended) for low-risk procedures 6, 5
For Intermediate-Risk Surgery
Apply this decision tree 1, 6:
If patient has excellent functional capacity (>10 METs) and no symptoms: Proceed with surgery despite EKG abnormalities 6
If patient has poor functional capacity (<4 METs) with 1-2 clinical risk factors: Consider noninvasive stress testing only if it will change management (Class IIb recommendation) 1
If new EKG abnormalities are found (ST changes, new Q waves, new bundle branch block, prolonged QT, new atrial fibrillation): Further evaluation is reasonable to refine risk assessment 6
For High-Risk/Vascular Surgery
- Patients with ≥3 clinical risk factors and poor functional capacity (<4 METs): Noninvasive stress testing is reasonable if it will change management (Class IIa) 1
- Abnormal exercise stress test at low workloads: Associated with 24% cardiac complication rate; warrants cardiology consultation 1
Common Pitfalls to Avoid
Pitfall #1: Delaying surgery for chronic, stable EKG findings
- A study of 1,149 preoperative EKGs found only 7.8% had significant abnormalities, and age >65 plus specific cardiac history were better predictors than EKG alone 7
- In day-case surgery, 26% had abnormal EKGs but only 20% had surgery postponed, with no adverse events in those who proceeded 8
Pitfall #2: Ordering routine EKGs without clinical indication
- This increases costs without improving outcomes 6
- EKG abnormalities in older patients are prevalent (75%) but nonspecific 3
Pitfall #3: Failing to assess functional capacity
- Functional capacity is more predictive than EKG findings 6
- Patients achieving >75% age-predicted maximum heart rate on stress testing have low risk regardless of EKG abnormalities 1
Pitfall #4: Not comparing with previous EKGs
- Chronic findings misinterpreted as acute may unnecessarily delay surgery 6
- An EKG obtained weeks before surgery remains valid if clinical status is unchanged 6
When to Obtain Cardiology Consultation
Consult cardiology before proceeding if 1, 4:
- New pathological Q waves with unknown cardiac history (obtain echocardiography to assess LV function) 4
- EKG changes suggesting acute ischemia (ST elevation/depression ≥1mm, new T-wave inversions) 2
- High-grade conduction abnormalities (Mobitz type II or complete heart block) 6
- Prolonged QT interval that may affect anesthetic selection 6
The Bottom Line
Proceed with surgery in patients with chronic, stable EKG abnormalities who are asymptomatic with reasonable functional capacity. 1, 3 Only delay surgery for active cardiac conditions requiring treatment or when further testing will genuinely change perioperative management 1, 6.