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“Q waves localize myocardial infarction.”

“ST segments can diagnose ischemia.”

  • The 12-lead ECG is a fundamental part of the evaluation for coronary artery disease.

  • Scrutinizing the ECG before performing an echo is good patient care.

  • Q waves in leads II, III, and AVF help in the sometimes difficult analysis of inferior left ventricular wall motion on the echo.

  • Every echocardiographer should be able to recognize classic left ventricular hypertrophy with strain on the ECG.

  • Dramatic T wave inversion on the ECG does not always indicate myocardial ischemia. Echo may help.

  • An echo with contrast may show a “spade-shaped” left ventricular cavity. This is caused by apical left ventricular hypertrophy. These patients may have giant T wave inversions on the ECG.

  • Low QRS voltage on the ECG is important to recognize in a patient with left ventricular hypertrophy on echo. This ECG–echo discordance suggests the presence of an infiltrative cardiomyopathy such as cardiac amyloidosis.

  • Patients with Ebstein abnormality of the tricuspid valve have conduction abnormalities on the ECG. Ebstein anomaly is rare, and a suspected diagnosis can be confirmed by echo. It is associated with the more prevalent Wolff-Parkinson-White (WPW) syndrome on the ECG. WPW is more common than Ebstein anomaly. A common phone call from the electrophysiology lab is a request for an echo in a patient with an accessory pathway (WPW).

  • Arrhythmias such as atrial fibrillation are sometimes the first manifestation of previously unsuspected valvular regurgitation, cardiomyopathy, and pericardial and congenital heart disorders. Electrophysiologists have many adult patients with congenital heart disease.

  • Takotsubo cardiomyopathy may mimic acute anterior myocardial infarction on the ECG.

  • If the P wave is >3 mm tall in lead II, look for right atrial enlargement on echo.

  • If the P wave is prolonged in lead II, and predominantly negative in V1, look for left atrial enlargement on echo.

  • It is always worthwhile to review the electrocardiogram and to know about disorders that may affect the ECG.

Practical Example

  • Causes of tall R waves on the electrocardiogram in lead V1:

    • - Posterior extension of inferior myocardial infarction.

    • - Right ventricular hypertrophy.

    • - Duchenne muscular dystrophy.

    • - Dextrocardia.

    • - WPW syndrome.

    • - Ventricular tachycardia.

    • - Normal variant in the young.


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  • Kosuge M, Kimura K. Electrocardiographic findings of takotsubo cardiomyopathy as compared with those of anterior acute myocardial infarction. J Electrocardiol. 2014;47:684–689.

  • Murtagh B, Hammill SC, Gertz MA, et al. Electrocardiographic findings in primary systemic amyloidosis and biopsy-proven cardiac involvement. Am J Cardiol. 2005;95:535–537.

  • Riera AR, Uchida AH, Schapachnik E, et al. Early repolarization variant: epidemiological aspects, mechanism, and differential diagnosis. Cardiol J. 2008;15:4–16.

  • Yamaguchi H, Ishimura T, Nishiyama S, et al. ...

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