Pseudoinfarct

1. In left ventricular hypertrophy, there is often a QS deflection or poor R wave progression in the right precordial leads that suggests anterior myocardial infarction. The secondary ST-segment elevation in these leads may be mistaken as a current of injury.

2. In pulmonary emphysema, the R waves in the right precordial and sometimes midprecordial leads become quite small or are absent, suggesting anterior myocardial infarction. These QRS changes are explained by the vertical displacement of the heart secondary to a low-lying diaphragm and the intervention of hyperinflated lungs.

3. The pseudoinfarction pattern may also be seen in patients with pneumothorax. The voltage of the QRS complex may be reduced. QS deflection may appear in the right precordial leads.

4. In pulmonary embolism, the Q waves in lead III (as part of the S1Q3 pattern), and sometimes in lead aVF, that are accompanied by ST-segment and T-wave changes are often interpreted as inferior myocardial infarction. In addition to T-wave inversion, with or without an rSr′ pattern in the right precordial leads due to acute right heart strain, QS complexes with ST-segment elevation may occasionally develop in these leads and mimic acute anterior myocardial infarction.

5. In hypertrophic cardiomyopathy, abnormal Q waves are often seen, especially in the left precordial leads and lead I. These Q waves have been attributed to ventricular septal hypertrophy.

6. Myocardial fibrosis is often responsible for the pseudoinfarction pattern in patients with dilated cardiomyopathy, progressive muscular dystrophy, Friedreich’s ataxia, scleroderma, amyloidosis, and primary and metastatic tumors of the heart.

7. QS deflections are often seen in the right precordial leads in patients with complete left bundle branch block in the absence of myocardial infarction.

8. Left anterior hemiblock is occasionally associated with small Q waves in the precordial leads that mimic anterior myocardial infarction.

9. The delta waves in Wolff-Parkinson-White syndrome are frequently interpreted as abnormal Q waves of myocardial infarction.

10. Pheochromocytoma may be associated with striking ECG changes masquerading as ischemic heart disease.4

11. Other conditions that may be associated with ECG changes simulating myocardial infarction include intracranial hemorrhage, hyperkalemia and, as mentioned above, acute pericarditis.

Pseudoinfarctions | Circulation