?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.title=Mahaim+Fibre+Tachycardia%3A+Recognition+and+Management%0A&rft.creator=Sternick%2C+Eduardo+Back&rft.subject=Indian+Pacing+and+Electrophysiology+Journal&rft.description=%0A%0A+++++++++++Dr.+Gallagher+et+al1+wrote+22+years+ago+that+%22the+role+of+Mahaim+fibers+in+the+genesis+of+cardiac+arrhythmias+in+man+has+been+controversial+since+they+were+first+described+%22+in+the+late+30's+by+Dr.+Ivan+Mahaim2.+The+very+early+reports+were+strictly+anatomical+studies2%2C3%2C4%2C5%2C6.+This+histopathologic+quest+did+not+end+yet.+Mahaim+fibers+were+supposed+to+be+accessory+connections+taking+off+from+the+His+bundle+and+fascicles+(FV-fasciculoventricular)+to+the+right+ventricle+or+from+the+atrioventricular+node+(NV-nodoventricular+fibers)+to+the+right+ventricle.+Anderson+et+al7+proposed+2+varieties+of+NV+fibers%2C+one+that+arises+from+the+transitional+zone+and+the+other+which+inserted+from+the+deep%2C+compact+nodal+portion+of+the+AV+junction.+In+his+pioneering+work+HJJ+Wellens+paved+the+road+for+clinical+electrophysiological+investigation.+He+was+the+first+to+study+a+patient+with+accessory+pathway+with+decremental+properties+and+long+conduction+times+assuming+its+relationship+with+the+fibers+described+long+ago+by+%22Mahaim%22%2C+as+reported+in+his+doctoral+thesis8+in+1971.+The+term+nodofascicular+(NF)+was+applied+when+the+retrograde+His+bundle+potential+preceded+the+ventricular+deflection%2C+while+nodoventricular+pathway+would+be+appropriate+when+the+retrograde+His+bundle+deflection+followed+the+ventricular+potential.+It+took+some+years+to+electrophysiologists+realize+the+conceptual+mismatch+among+the+%22Mahaim%22+physiology+and+structure+described+by+Mahaim+et+al.+An+important+observation+was+done+in+1978+by+Becker+et+al5+who+found+an+accessory+node+associated+with+a+bundle+of+specialized+fibers+measuring+1+cm+and+coursing+through+the+right+ventricle%2C+mimicking+a+second+AV+conduction+system+located+on+the+lateral+tricuspid+annulus.+However%2C+that+did+not+change+the+mainstream+concept+of+NV+fibers.+During+the+early+80's+many+centers+started+to+refer+patients+with+drug+refractory+tachycardias+to+surgical+treatment.+According+to+the+current+concepts+at+that+time+targeting+the+A-V+node+would+be+the+logic+strategy+for+curative+treatment+of+patients+with+NV%2FNF+fibers.+Some+courageous+electrophysiologists+used+a+new+technique+consisting+of+high-energy+catheter+ablation+of+the+A-V+node+to+treat+a+patient+with+%22Mahaim%22+fiber%2C+which+yielded+complete+AV+block+and+persistent+preexcitation9.+The+turning+point+came+in+1988+at+the+University+Hospital+of+Western+Ontario%2C+Canada%2C+when+Klein%2C+Guiraudon+et+al10+had+decided+to+extensively+freeze+the+A-V+node+and+upper+His+bundle+region+of+a+29+year+old+man+and+they+soon+realized+that+preexcitation+did+not+go+away.+It+became+clear+for+them+that+his+accessory+pathway+was+not+linked+whatsoever+to+the+A-V+node.+The+next+patient+was+luckier%2C+and+had+kept+intact+his+A-V+node%2C+while+his+%22Mahaim+fibers%22+were+successfully+severed+after+ice+mapping+produced+a+consistent+zone+of+reversible+block+in+the+accessory+pathway+at+the+right+lateral+aspect+of+the+tricuspid+annulus.+Klein's+manuscript+was+received+on+August+24%2C+1987%2C+and+published+the+next+year+on+JACC.+Two+months+later+(October+20%2C+1987)+Circulation+received+a+manuscript+from+Tchou+P+et+al11+entitled+%22Atriofascicular+connection+or+a+nodoventricular+fiber%3F+Electrophysiologic+elucidation+of+the+pathway+and+associated+reentrant+circuit%22.+From+a+single+case+report+we+were+taught+how+simple+it+is+to+make+sure+that+such+pathways+arise+from+the+atrium.+In+recent+years+catheter+ablation+techniques+have+shed+more+light+on+the+subject.+Discrete+%22Mahaim%22+potentials+that+are+considered+surrogates+of+pseudo-Mahaim+tissue+depolarization%2C+are+used+as+an+effective+target+for+ablation12%2C13.+A+number+of+pharmacologic14+and+histologic+data5%2C6%2C15%2C16%2C+electrophysiologic+maneuvers+and+observations+during+radiofrequency+catheter+ablation+like+heat+induced+%22Mahaim%22+automaticity19%2C20+are+regarded+as+evidences+of+either+an+ectopic+A-V+node+or+remnants+of+the+specialized+A-V+ring+tissue.+The+NV%2FNF+fibers+are+now+considered+a+rare+item+but+there+are+some+convincing+reports21+of+narrow+and+regular+QRS+tachycardias+with+ventriculoatrial+dissociation.+The+last+variety+which+is+known+as+fasciculoventricular+pathway22+seems+to+play+no+role+in+clinical+tachycardias+but+as+long+as+it+is+very+often+associated+with+bypass+tracts+they+should+be+correctly+recognized+and+not+targeted+for+ablation%2C+avoiding+unnecessary+damage+to+the+A-V+node-His+bundle+conduction+system.&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=2003-04&rft.type=Journal+(Paginated)&rft.type=PeerReviewed&rft.format=text%2Fhtml&rft.identifier=http%3A%2F%2Fcogprints.org%2F4284%2F1%2Fsternick.htm&rft.identifier=++Sternick%2C+Eduardo+Back++(2003)+Mahaim+Fibre+Tachycardia%3A+Recognition+and+Management.++%5BJournal+(Paginated)%5D+++++&rft.relation=http%3A%2F%2Fcogprints.org%2F4284%2F