What are the next steps after an abnormal ECG (electrocardiogram) reading?

Next Steps After an Abnormal ECG Reading

All abnormal ECG findings require immediate cardiology referral and comprehensive cardiac evaluation to exclude underlying structural heart disease or primary electrical disorders that could lead to sudden cardiac death. 1

Immediate Actions

Temporary restriction from athletic activity should be considered for any abnormal ECG of uncertain clinical significance until secondary investigations are completed. 1

• Initial evaluation of all ECG abnormalities must be performed under the direction of a cardiologist 1
• Additional testing will be guided by initial findings, clinical suspicion, presence of symptoms (chest pain, dyspnea, palpitations, syncope), or family history of inherited cardiac disease or sudden cardiac death 1, 2

Systematic Evaluation Based on Specific ECG Abnormality

For T-Wave Inversions (≥1 mm depth in ≥2 contiguous leads)

Lateral or inferolateral T-wave inversion requires comprehensive investigation with echocardiography as first-line, followed by cardiac MRI with gadolinium if echocardiography is non-diagnostic. 1

• Echocardiography is the initial recommended test 1
• If echocardiography is not diagnostic, cardiac magnetic resonance imaging (CMR) with gadolinium should be utilized to assess for cardiomyopathy, especially in the left ventricular apex and lateral free wall 1
• Exercise ECG testing and minimum 24-hour Holter monitoring should be performed 1
• Consider signal-averaged ECG (SAECG) based on findings 1

For Ventricular Arrhythmias (including couplets, triplets, accelerated ventricular rhythm, non-sustained VT)

A comprehensive cardiac evaluation including echocardiography, CMR, minimum 24-hour ECG monitor, and exercise ECG test is required to rule out myocardial disease and primary electrical disease. 1

• If >2,000 premature ventricular contractions or non-sustained ventricular tachycardia are present on initial testing, comprehensive cardiac testing inclusive of CMR is warranted to investigate for myocardial disease 1

For Prolonged QTc Interval

Do not diagnose Long QT Syndrome based on a single ECG reading; repeat the ECG on a separate day and obtain detailed personal and family history. 1

• Repeat resting ECG on a separate day 1
• Review personal history of syncope, seizures, and family history of exertional syncope, 'epilepsy', postpartum-timed syncope/seizure, unexplained motor vehicle accidents, unexplained drowning, and premature unexplained sudden death <50 years 1
• Consider exercise ECG test, laboratory electrolyte screening, family screening, and genetic testing when clinical suspicion is high 1
• Acquire ECG of first-degree relatives if possible 1
• If QTc ≥500 ms, refer immediately to a heart rhythm specialist or sports cardiologist 1
• A QTc <500 ms in the absence of symptoms or familial disease is unlikely to represent LQTS 1

For Brugada Type 1 Pattern

Immediate referral to a cardiologist or heart rhythm specialist is required. 1

• Consider high precordial lead ECG with leads V1 and V2 in 2nd intercostal space or sodium channel blockade if Brugada pattern is indeterminate 1
• Consider genetic testing and family screening 1

For Advanced 2° or 3° Atrioventricular Block

Perform echocardiography, minimum 24-hour ECG monitor, and exercise ECG test. 1

• Consider laboratory screening and CMR based on echocardiography findings 1

For Atrial Tachyarrhythmias

Perform echocardiography, minimum 24-hour ECG monitor, and exercise ECG test. 1

• Consider CMR or electrophysiology study based on clinical suspicion 1

For Profound Sinus Bradycardia (<30 beats/min) or Profound 1° AV Block (≥400 ms)

Repeat ECG after mild aerobic activity. 1

• Consider additional testing based on clinical suspicion 1

For Ventricular Pre-excitation (Wolff-Parkinson-White)

Perform exercise ECG test to assess pathway risk. 1

• Abrupt cessation of the delta wave (pre-excitation) on exercise ECG denotes a low-risk pathway 1
• Electrophysiology study for risk assessment should be considered if a low-risk accessory pathway cannot be confirmed by non-invasive testing 1
• Consider EP study for moderate to high-intensity sports 1

For Two or More Borderline ECG Findings

Perform echocardiography and consider additional testing based on clinical suspicion. 1

Critical Clinical Context Considerations

• ECG interpretation must always be performed in the clinical context of the patient 2
• For patients with acute symptoms suggesting life-threatening conditions, in-person evaluation in an emergency setting is preferable to remote ECG image evaluation 2
• Current ECG tracings should always be compared with previous tracings 3
• ECG alone may not be sufficient for definitive diagnosis in complex cases, and additional cardiac testing may be necessary 2

Common Pitfalls to Avoid

• Do not rely solely on computerized ECG interpretations - they can be a source of erroneous information and must be verified by physician interpretation 4
• Do not dismiss a single abnormal finding - even isolated abnormalities warrant comprehensive evaluation to prevent sudden cardiac death 1
• Do not allow patients to continue high-intensity athletic activity with unresolved abnormal ECG findings, as this increases risk of adverse cardiac events 1
• Do not forget to screen first-degree relatives when inherited cardiac disease is suspected, particularly with QT prolongation or Brugada patterns 1