Uncommon cause of ST-segment elevation in V1-V3: incremental value of cardiac magnetic resonance imaging.

Abstract

Sirs:Although ST-segment elevation in precordial leads is acharacteristic of anterior left ventricular infarction (LVI), itmay also be observed in patients with proximal right cor-onary occlusion. An isolated right ventricular infarction(RVI) accounts for only 3 % of all myocardial infarctions(MI) [1]; in these cases, the ST-segment elevation in theprecordial leads V1–V3 also may occur in the absence ofinferior electrocardiographic changes [2], whereas thecombination of RVI with inferior LVI suppresses ST-seg-ment elevation in the precordial leads and yields an ST-segment elevation in leads DII, DIII, and aVF [3].Although certain electrocardiographic features have beensuggested to help differentiate ST-segment elevation sec-ondary to isolated RVI from LVI [3], it may be impossibleto make a differential diagnosis on the basis of electro-cardiography alone because these features are not patho-gnomonic. Furthermore, when a patient is admitted fortypical chest pain, slight ST-segment elevation in leadsV1–V3 and significant increase of cardiac troponin butwith normal coronary main vessels at the coronary angi-ography, the diagnosis of a RVI is challenging; taking intoaccount the multiple causes of myocardial injury andtreatment consequences, there is great clinical need toclarify the underlying reason for cardiac troponin release.Although some studies report that echocardiography is avaluable clinical tool for the evaluation of global RVfunction [4], geometric assumptions in modeling thecomplex RV shape restricts the ability of this technique inaccurate and precise quantification of RV function; fur-thermore, RV function assessment can be difficult inpatients with poor acoustic window or when minor alter-ations of RV function are present.Cardiac magnetic resonance (CMR) provides a com-prehensive, multifaceted view of the heart and can beuseful to characterize an infarct site and size accurately [5].CMR inthisparticularsettingcan confirm the presence ofa minor RVI and aid to exclude other potential causes oftroponin rise with normal coronary main vessels at the cor-onaryangiography,suchasembolicmyocardialinfarctionormyocarditis [6]. Acute MI treatment [7–10] and traditionalpredictors of long-term mortality after acute MI are wellcharacterized [11–14] but with introduction of CMR, newpredictorsofcardiovasculareventsareemerging[15,16]andthe evaluation of RV function using CMR can improve riskstratificationandpotentially refinepatient management afterMI [17]. Moreover, the extent of myocardial scar charac-terized by CMR is significantly associated with the occur-rence of spontaneous ventricular arrhythmias [18].There have been few reports of anterior ST-segmentelevation caused by isolated RVI due to right ventriclebranch occlusion [19–21]. Occlusion of the conus branchhas been described essentially as a complication of coro-nary angioplasty or during cardiac surgery [19–21]. Onlyone report described a spontaneous RVI with culprit lesionin the conus branch [22]. Assessment of isolated RVI dueto a critical stenosis of the conus branch by magnetic res-onance is never been reported.