What are the next steps if an ECG indicates abnormal heart activity?

Management of Abnormal ECG Findings

When an ECG indicates abnormal heart activity, a systematic cardiac evaluation should be performed under the direction of a cardiologist, with additional testing guided by the specific abnormality detected and clinical suspicion. 1, 2

Initial Assessment Based on ECG Abnormality

• Abnormal ECG findings require further assessment to exclude the presence of intrinsic cardiac disease, and temporary restriction from athletic activity should be considered until secondary investigations are completed 1

• T-wave inversion ≥1 mm in depth in two or more contiguous leads (excluding leads aVR, III, and V1) in anterior, lateral, inferolateral, or inferior territory is abnormal and requires prompt evaluation 1, 3

• Ventricular arrhythmias (including couplets, triplets, accelerated ventricular rhythm, and non-sustained ventricular tachycardia) require a comprehensive cardiac evaluation to rule out myocardial disease and primary electrical disease 1

• Atrial tachyarrhythmias require echocardiography, 24-hour ECG monitoring, and exercise ECG testing to evaluate for underlying myocardial or electrical disease 1

• Advanced 2nd or 3rd-degree atrioventricular block requires echocardiography, 24-hour ECG monitoring, and exercise ECG testing 1

Specific Evaluation Protocols by ECG Finding

For T-wave Inversion:

• Lateral or inferolateral T-wave inversion requires comprehensive investigation including echocardiography and cardiac MRI with gadolinium to exclude cardiomyopathy 1, 3

• T-wave inversion in right precordial leads (V1 to V3) or beyond in the absence of complete RBBB is common in arrhythmogenic right ventricular cardiomyopathy (ARVC) and requires thorough evaluation 1, 4

• Biphasic T-waves where the negative portion is ≥1 mm in depth in ≥2 leads should be evaluated similarly to T-wave inversions 1

For Ventricular Pre-excitation (WPW):

• Exercise ECG testing to assess for abrupt cessation of the delta wave (indicating a low-risk pathway) 1

• Consider electrophysiology study for risk assessment if a low-risk accessory pathway cannot be confirmed by non-invasive testing 1

For Prolonged QTc:

• Repeat resting ECG on a separate day 1

• Consider exercise ECG test, laboratory screening for electrolyte abnormalities, family screening, and genetic testing when clinical suspicion is high 1

• Direct referral to a heart rhythm specialist for QTc ≥500 ms 1

For Brugada Type 1 Pattern:

• Immediate referral to a cardiologist or heart rhythm specialist 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

Comprehensive Cardiac Evaluation

• Echocardiography is the first-line imaging test for most abnormal ECG findings to assess for structural heart disease 1, 2

• 24-hour ECG monitoring (minimum) is essential for evaluating arrhythmias and conduction abnormalities 1, 2

• Exercise ECG testing provides valuable information about exercise capacity, chronotropic response, heart rate recovery, and blood pressure response to exercise 1

• Cardiac MRI with gadolinium should be utilized if echocardiography is not diagnostic, especially for suspected cardiomyopathies 1, 2

• Signal-averaged ECG (SAECG) should be considered for patients with multiple premature ventricular contractions 1

Special Considerations

• In athletes, temporary restriction from athletic activity should be implemented until secondary investigations are completed for abnormal ECGs of uncertain clinical significance 1, 2

• For symptomatic women with intermediate ischemic heart disease risk who can exercise at >5 METs and have a normal rest ECG, exercise treadmill testing is recommended as the initial test of choice 1

• In pre-operative settings, abnormal ECG findings may necessitate postponement of elective procedures until cardiac evaluation is complete 2

• The presence of an abnormal ECG is a multivariate predictor for arrhythmia or death within 1 year, emphasizing the importance of thorough evaluation 2

Common Pitfalls to Avoid

• Do not dismiss T-wave inversion in V1-V2 as a normal variant without proper evaluation, especially with elevated troponin 4

• A single normal echocardiogram does not exclude the possibility of developing cardiomyopathy in the future; serial ECGs and echocardiography may be necessary 4

• Do not rely solely on computer ECG interpretations; all computer ECG interpretations should be verified by a qualified physician 1, 5

• Avoid missing the distinction between physiological adaptations (especially in athletes) and pathological conditions requiring intervention 1, 2