Resumo

BARON C, Alberto. Right ventricular infarction. Rev. Col. Cardiol. [online]. 2007, vol.14, n.2, pp.93-99. ISSN 0120-5633.

In general, right ventricular infarction is associated with left ventricular inferior wall infarction. Obstructive chronic pulmonary disease and right ventricular hypertrophy are predisposing factors. It usually occurs as a consequence of proximal obstruction of the right coronary artery, which leads to right systolic and diastolic ventricle dysfunction. Stroke volume is diminished and diastolic volume and right ventricular filling pressure increase, causing hypotension and peripheral congestion. Pulmonary blood flow and left ventricular venous return are diminished, which may lead to shock. Besides, complications such as atrioventricular block, sinus dysfunction and ventricular aneurysm may occur. The electrocardiogram shows ST elevation in leads III, V1 to V3 and in V4R. The echocardiogram shows right ventricular free wall hypokinesis or akinesis and there is right cavities dilation and tricuspid regurgitation. The Doppler shows an increment in the duration of isovolumetric contraction and relaxation intervals; the ejection period is shortened and the myocardial performance index increase to abnormal values. The tissue Doppler is abnormal because of the decrease of systolic velocity in the tricuspid annulus. The optimization of rhythm and heart rate is an important part of treatment, and by this reason, beta-blockers may be avoided; depending on the severity of bradycardia, atropine, aminophylline or transient pace-maker can be used in order to ensure an adequate heart rate. In case of atrial fibrillation, anti-arrhythmic drugs or electric cardioversion may be used. An adequate filling volume may be guaranteed for maintaining the central venous pressure over 15 mm Hg. The use of vasodilators and diuretics is contraindicated. It is important the quick recanalization of the obstructed artery through thrombolisis or angioplastia. If the low cardiac output signs persist, a parenteral inotropic must be used. Intra-aortic balloon pump or mechanic assistance device can be used.Recently, the use of nitric oxide for pulmonary vascular resistance reduction and enhancement of heart output have been described.

Palavras-chave : myocardial infarction; cardiogenic shock; right coronary artery; right ventricular systolic function.

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