An acute pulmonary embolus may cause ECG changes that reflect the sudden increase in pulmonary artery pressure, right ventricular dilatation and cardiac rotation that occur in this setting and that characterize acute cor pulmonale. In addition, there is frequently hypoxemia and a decrease in cardiac output which result in sinus tachycardia and/or supraventricular arrhythmias. The most characteristic electrocardiographic changes associated with a pulmonary embolus are listed here.
