?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.title=Optical+Mapping+Of+Cardiac+Arrhythmias&rft.creator=Arora%2C+Rishi&rft.creator=Das%2C+Mithilesh+K&rft.creator=Zipes%2C+Douglas+P&rft.creator=Wu%2C+Jianyi&rft.subject=Indian+Pacing+and+Electrophysiology+Journal&rft.description=The+concept+of+mapping+rhythmic+activation+of+the+heart+dates+back+to+the+beginning+of+last+century%2C+with+initial+descriptions+of+reentry+in+turtle+hearts1%2C+to+the+first+systematic+mapping+of+sinus+rhythm+and+then+atrial+flutter+by+Lewis+et+al2.+Barker+et+al3+were+the+first+to+map+the+human+heart.+Initial+mapping+was+primarily+performed+using+single+probes+to+record+activation+in+different+regions+of+the+heart.+The+1960%E2%80%99s+and+70%E2%80%99s+saw+the+development+of+computerized+mapping+of+the+human+heart%2C+e.g.+in+the+cure+of+Wolf-Parkinson-White+syndrome+as+well+as+in+the+study+of+Langendorff+preparations4.+In+fact%2C+most+of+the+recent+advances+in+cardiac+mapping+have+focused+on+improvements+in+multisite+recordings+within+the+heart%2C+with+the+ability+to+simultaneous+record+electrical+activation+from+several+hundreds+of+sites+having+contributed+significantly+to+our+understanding+of+atrial+and+ventricular+arrhythmias.+%0A++++++++++++Despite+these+recent+advances%2C+multisite+contact+mapping+suffers+from+several+limitations%2C+including+the+technical+problems+associated+with+amplification%2C+gains%2C+sampling+rates%2C+signal-to-noise+ratio%2C+and+the+inability+to+see+signals+during+high-voltage+shocks.+In+addition%2C+an+intrinsic+limitation+of+current+mapping+techniques+is+their+inability+to+provide+information+about+repolarization+characteristics+of+electrically+active+cells%2C+thereby+limiting+our+ability+to+study+entire+action+potentials.+In+fact%2C+intracellular+microelectrode+recordings+are+still+considered+the+gold+standard+for+the+study+of+action+potential+characteristics+in+whole+tissue.+Microelectrode+techniques+are+limited+however%2C+by+an+inability+to+record+action+potentials+from+several+sites+simultaneously%2C+thereby+precluding+their+use+in+high-density+activation+mapping.++%0A++++++++++++In+part+due+to+the+above-mentioned+limitations%2C+the+last+few+years+have+seen+the+development+and+use+of+voltage-sensitive+dyes+as+a+means+to+map+not+only+activation%2C+but+repolarization+as+well.+Voltage-sensitive+dyes%2C+when+excited%2C+provide+an+optical+signal+that+mimics+an+action+potential+and+thus+allows+the+visualization+of+both+activation+and+recovery+processes+in+any+region+under+view.+This+allows+one+to+precisely+evaluate+the+propagation+of+a+wave+of+excitation+and+to+measure+its+wavelength+visually.+%0A++++++++++++Optical+mapping+techniques+use+imaging+devices+such+as+a+photodiode+array+or+a+charge-coupled+device+video+camera+with+the+heart+being+illuminated+and+either+continuously+or+spatially+scanned.+The+basis+for+these+techniques+is+the+use+of+voltage-sensitive+dyes+that+bind+to+or+interact+with+cell+membranes.+%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=2003-12&rft.type=Journal+(Paginated)&rft.type=PeerReviewed&rft.format=text%2Fhtml&rft.identifier=http%3A%2F%2Fcogprints.org%2F4242%2F1%2Fwu.htm&rft.identifier=++Arora%2C+Rishi+and+Das%2C+Mithilesh+K+and+Zipes%2C+Douglas+P+and+Wu%2C+Jianyi++(2003)+Optical+Mapping+Of+Cardiac+Arrhythmias.++%5BJournal+(Paginated)%5D+++++&rft.relation=http%3A%2F%2Fcogprints.org%2F4242%2F