The vectorcardiogram of cardiac infarction.

Abstract

were studied andfoundtohavecertain constant characteristics thatwerecomparable withtheresults obtained byelectronic methods. Inthispaperwereport thevectorcardiographic findings of extensive cardiac infarction, andtheabnormal patterns obtained havebeenrelated totheQRS-T complexes recorded fromthesamepatients intheconventional manner.Duchosal andSulzer (1949) andVastesaeger (1949) havestudied thevectorcardiogram ofcardiac infarction, using an electronic apparatus. Ourfindings areinsubstantial agreement withthose recently reported by Scherlis andGrishman (1951); their three-plane vectorcardiograms wereseensimultaneously ona tribeam cathode-ray tubeandphotographed ononefilm. METHIOD Themethodofintegrating thescalar electrocardiograms hasbeenthesameaswedescribed, butthe leadpositions ofthereference system havebeenslightly modified. Thevoltage obtained fromleads in thehorizontal plane inthesystem advocated byDuchosal andSulzer (1949) issmall, anditwasfound that thehigher voltage that could beobtained bybringing theelectrodes nearer totheheart, madethe vectorcardiogram easier tocorrelate withtheconventional chest leads. Thehorizontal leadpositions have therefore beenraised fromtheiliac spine level toaplane through thexiphisternum; thereference system -then becomes almost cuboidal. Itisappreciated thatthere arecertain theoretical objections toplacing electrodes anynearer theheart, butthis newposition isconsidered tobeareasonable compromise that sacrifices little fundamental accuracy andfacilitates interpretation oftheloop.Grishman etal.(1951) havemadesimilar changes intheleadpositions. Thevalidity ofthis methodisshownbythesimilarities oftheQRScomplexes reconstructed fromour vectorcardiograms andtheactual leads obtained bytheconventional method.InFig.IAthereconstructed QRScomplexes fromthefrontal plane looparecompared withthestandard leads recorded from thesamenormal subject. A reconstruction oftheunipolar chest leads fromthehorizontal plane loopis showninFig. 2Atogether withtherecorded unipolar chest leads. Theprojections inthree planes of thespatial vectorcardiogram havebeendrawnin20cases ofcardiac infarction, ofwhich10wereanterior -and10posterior inposition. Allobservations weremadewiththesubject inareclining position. Each patient hadahistory ofprolonged chest pain atrest, andanelectrocardiogram thatshowed pathological Q waves. RESULTS Fourexamples ofthevectorcardiogram inpatients withposterior cardiac infarction areshown inFig. 3,andafrontal projection isshownwiththereconstructed complexes alongside therecorded limbleads inFig. lB.Allthepatients withthis condition showed loops that wereinitially directed upwards inthefrontal plane andtended tolieintheupperquadrants; thesagittal view(Fig. 3) -oftheloopshowsthesameupwards deviation. Thehorizontal projection showednoconstant 339