ECG Interpretation

Electrocardiography(ECGorEKG*)istheprocessofrecordingtheelectricalactivityoftheheartoveraperiodoftime.AtypicalECGtracingisarepeatingcycleofthreeelectricalentities:aPwave(atrialdepolarization),aQRScomplex(ventriculardepolarization)andaTwave(ventricularrepolarization).TheECGistraditionallyinterpretedmethodicallyinordertonotmissanyimportantfindings.

Innormalconditionaheartrateisbetween60to100beatsperminute.Below60heartrateissaidtobebradycardicandaratefasterthan100beatsperminuteissaidtobetachycardic.Manyathletescanhaveanormalrestingheartrateoflessthan60beatsaminute.

Theheart'selectricalaxisisthegeneraldirectionoftheventriculardepolarizationwavefront(ormeanelectricalvector)inthesagittalplane(theplaneofthelimbleadsandaugmentedlimbleads).

AnECGtracingisaffectedbypatientmotion.Somerhythmicmotions(suchasshiveringortremors)cancreatetheillusionofcardiacdysrhythmia.