?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.title=Left+Septal+Fascicular+Block%3A+Myth+Or+Reality%3F%0A&rft.creator=MacAlpin%2C+Rex+N.&rft.subject=Indian+Pacing+and+Electrophysiology+Journal&rft.description=Anatomic+studies+have+shown+that+the+left+bundle+branch+divides+into+three+fascicles+in+most+humans.+Changes+in+the+12+lead+ECG+(electrocardiogram)+due+to+conduction+abnormalities+of+the+left+anterior+fascicle+and+left+posterior+fascicle+are+now+part+of+the+standard+repertoire+of+electrocardiographic+interpretation.+There+are+no+standard+criteria+for+detecting+conduction+defects+involving+the+third+left+fascicle%2C+the+septal+or+median+fascicle%2C+and+the+very+existence+of+such+defects+is+still+a+matter+of+controversy.+The+purposes+of+this+article+are+to+review+the+available+evidence+on+this+subject%2C+suggest+electrocardiographic+criteria+for+its+recognition%2C+and+present+examples+which+illustrate+that+left+septal+fascicular+block+does+indeed+exist+as+a+specific+entity.+Left+septal+fascicular+block+is+a+polymorphic+conduction+defect+which+may+explain+some+previously+inadequately+understood+electrocardiographic+abnormalities.%0A&rft.publisher=Indian+Pacing+and+Electrophysiology+Group&rft.contributor=Singh%2C+Balbir&rft.contributor=Lokhandwala%2C+Yash&rft.contributor=Francis%2C+Johnson&rft.contributor=Gupta%2C+Anup&rft.date=2003-07&rft.type=Journal+(Paginated)&rft.type=PeerReviewed&rft.format=text%2Fhtml&rft.identifier=http%3A%2F%2Fcogprints.org%2F4280%2F1%2Fmacalpin.htm&rft.identifier=++MacAlpin%2C+Rex+N.++(2003)+Left+Septal+Fascicular+Block%3A+Myth+Or+Reality%3F++%5BJournal+(Paginated)%5D+++++&rft.relation=http%3A%2F%2Fcogprints.org%2F4280%2F