Other 12-Lead ECG Findings

Left Atrial Enlargement Left atrial enlargement is illustrated by increased P wave duration in lead II, top ECG, and by the prominent negative P terminal force in lead V1, bottom tracing.

LAE LAE is best seen in V1 with a prominent negative (posterior) component measuring 1mm wide and 1mm deep. There are also diffuse nonspecific ST-T T wave abnormalities which must be correlated with the patient's clinical status. Poor R wave progression in leads l V1- V3, another nonspecific finding, is also present.

Right Atrial Enlargement RAE is recognized by the tall (>2.5mm) P waves in leads II, III, avf.. RVH is likely because of right axis deviation (+100 degrees) and the Qr (or rsr') complexes in V1-2.

RAE/RVH In this case of severe pulmonary hypertension, RVH is recognized by the prominent anterior forces (tall R waves in V1-2), right axis deviation (+110 degrees), and "P pulmonale" " (i.e., right atrial enlargement). RAE is best seen in the frontal plane leads; the P waves in lead II are >2.5mm in amplitude.

Wellens Syndrome Wellens Syndrome is a cardiac syndrome which indicates a critical high grade occulsion of the proximal LAD. If not identified and properly treated the average time from onset of symptoms to an extensive anterior wall MI is 8 days.

Wellens Syndrome Differential Characteristics: Biphasic T waves in V2 and V3 are indicators of Wellens Sign Progressive, symetrical,, deep T wave inversion in V2 and V3. The slope of the T waves are generally at 60-90 90 Little or no enzyme elevation Little or no ST segment elevation No loss of precordial R waves

Wellens Sign Tends to appear during pain-free intervals

Wellens Syndrome

Brugada Syndrome Recently recognized as a cause of sudden death in apparently healthy individuals. Due to malfunctioning sodium channels. If identified, patients benefit from an implantable cardioverter-defibrillator defibrillator (ICD)

Brugada Syndrome

Hyperkalemia

Pulmonary Embolism 12-lead ECG from a patient with a massive PE. Echocardiography confirmed the ECG signs of right ventricular strain (symmetrical T-T wave inversion in the precordial leads V1 through V4).

Pulmonary Embolism This patient also demonstrated signs of major PE: a large thrombus in both main pulmonary arteries (chest CT) and right ventricular dysfunction (echocardiography) were documented. The ECG only revealed sinus tachycardia.

Carbon Monoxide Poisoning 12-lead ECG from a patient with severe CO poisoning (CO hemoglobin of 39.1%) showing signs of myocardial ischemia as suggested by T-T wave inversion in the precordial and inferior limb leads. An elevated troponin level (troponin I level of 11.8 µg/l) confirmed the presence of myocardial injury.

Hypothermia ECG from a patient with severe hypothermia (23.8 C C at presentation). Osborn waves (as depicted by the arrows) are present in all leads.

TCA Overdose ECG showing sinus tachycardia with widened QRS complex (110 ms) and marked deviation of the terminal portion of the QRS complex in lead I (deep S wave) and avr (large R wave). Findings are consistent with TCA poisoning (plasma concentration of 1,258 ng/ml).

Trauma and the 12-Lead ECG

Myocardial Contusion ECG changes associated with myocardial contusion after blunt chest trauma may include STsegment elevation, T wave inversion, and development of Q waves. ECG on admission

Myocardial Contusion Shearing and compressive forces may cause an injury pattern. Right ventricle most commonly injured. ECG 48 hours post-admission

Subarachnoid Hemorrhage ECG from a patient with an acute subarachnoid hemorrhage. Note the inverted T waves in the precordial and lateral leads, which can mimic the changes seen with myocardial ischemia. In this patient, the QT interval was markedly prolonged (QTc = 613 ms).

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