BASIC DYSRHYTHMIA
INTERPRETATION QUESTIONS AND
ANSWERS
GeneralgvRulesgv-gvANS--
Firstgvandgvmostgvimportant,gvlookgvatgvyourgvpatient.gvReadgvleftgvtogvright.gvApplygvthegv
systematicgvapproach.gvAvoidgvshortcutsgvandgvassumptions.gvAskgvandgvanswergveachg
vquestiongvingvthegvECGgvanalysisgvapproach.
ECGgvRhythmgvAnalysisgv-gvANS--
AnalyzegvPgvwavesgv(Pgvwavegvisgvpresent,gvshapegvisgvconsistent,gvmustgvbegvbeforegve
achgvQRS),gvAnalyzegvQRSgvcomplexgv(presentgvandgvconsistent),gvDeterminegvatrialgvr
hythmgvorgvregularitygv(assessinggvP-PgvintervalgvorgvR-
Rgvinterval),gvDeterminegvventriculargvrhythmgvorgvregularitygv(assessinggvR-
Rgvinterval),gvDeterminegvHeartgvRate,gvMeasuregvthegvPRgvintervalgv(measurementgvsh
ouldgvbegvconstantgvandgvshouldgvbegvbetweengv0.12-
0.20gvsec),gvMeasuregvthegvQRSgvdurationgv(measurementgvshouldgvbegvconstantgvandgv
shouldgvbegvbetweengv0.04-0.10gvsec),gvinterpretgvthegvrhythm
Artifactsgv-gvANS--Wave-formsgvoutsidegvthegvheart-interference.gvCausedgvby:
gvPatentgvmovement,gvloosegvorgvdefectivegvelectrodes,gvimpropergvgrounding,gvfaultygvE
CGgvapparatus.
SinusgvRhythmsgv-gvANS--
Normal,gvSinusgvBradycardia,gvSinusgvTachycardia,gvSinusgvArrhytmia,
NormalgvSinusgvRhythmsgv-gvANS--
SAgvnodegvgeneratesgvimpulsegvthatgvfollowedgvagvnormalgvpathway.gvheartgvrategvfallgvw
ithingv60-
100gvBPM,gvatrialgvandgvventriculargvrhythmsgvaregvnormal,gvpgvwavegvprecedesgveverygv
QRS,gvPRgvintervalgvisgvwithingv0.12-0.20,gvQRSgvisgvwithingv0.12gvseconds.
AtrialgvRhythmsgv-gvANS--
AtrialgvDysrhythmias,gvPrematuregvAtrialgvContractionsgv(PAC),gvAtrialgvTachycardiagv(un
ifocal,gvmultifocal),gvAtrialgvFlutter,gvAtrialgvFibrillation
SinusgvBradycardiagvfeaturesgv-gvANS--
SAgvnodegvfiresgvslowergvthangvnormalgvHRgv(<60gvbpm),gvrhythmgvisgvregular,gvPgvwave
gvuprightgvandgvsamegvshape,gvPRgvisgvconstantgv0.12-0.20,gvQRSgv-normalgv<0.12gvsec
SinusgvBradycardiagvinformationgv-gvANS--
Causes:gvvagalgvstimulation,gvMI,gvHypoxia,gvDigitalisgvtoxicitygv(herbalgvmeds),gvMedicat
, iongvsidegveffects,gvnormalgvtogvelitegvaerobicallygvfitgvathletesgv(pumpsgvmoregvblood/
beat)
Adversegveffects:gvDizziness,gvweakness,gvsyncope,gvdiaphoresis,gvpallor,gvhypotension
Treatment:gvAccordinggvtogvsymptoms,gvatropinegvtogvspeedgvupgvheartgvrate,gvpacemak
er
SinusgvTachycardiagvfeaturesgv-gvANS--
SAgvnodegvfiresgvatgvagvrategvfastergvthangvnormal,gv>100gvbpmgvbutgvconductiongvpathw
aygvisgvnormal.gvAllgvcriteriagvforgvinterpretationgvaregvthegvsamegvexceptgvthatgvthegvheart
gvrategvisgvfaster.
SinusgvTachycardiagvinformationgv-gvANS--
Causes:gvemotionallygvupset,gvpain,gvfever,gvthyrotoxicosisgv(hyperthyroid),gvhypoxia,gvh
ypovolemia,gvinhibitiongvofgvvagusgvnervegv(parasympathetic)
Adversegveffects:gvAngina,gvdizziness,gvhypotension,gvincreasedgvingvcardiacgvworkloadg
v
Treatment:gvTreatgvthegvcause,gvmedicationsgvmaygvbegvgivengv(b-blockers)
SinusgvArrhythmiagv-gvANS--
Thegvonlygvirregulargvrhythmgvfromgvthegvsinusgvnodegvandgvhasgvagvcyclicgvpatterngvthatg
vusuallygvcorrespondsgvwithgvbreathing,gvRate=gvvariesgvwithgvrespiratorygvpattern,gvReg
ularity=gvirregulargvingvagvrepetitivegvpattern,gvPgvwave=gvuprightgvingvmostgvleads,gvsame
gvshapegvandgvonegvtogveachgvQRS;P-
Pgvintervalgvisgvirregular,gvQRS=gv<0.12,gvCause=gvusuallygvbreathinggvpatterngvbutgvcan
gvalsogvbegvheartgvdisease,gvTx=gvUsuallygvnongvrequired
AtrialgvDysrhythmiasgv-gvANS--
SAgvnodegvfailsgvtogvgenerategvangvimpulsegv(atrialgvtissuegvtakesgvover),gvAtrialgvnodesgv
orgvinternodalgvpathwaysgvmaygvinitiategvangvimpulsegvandgvfollowsgvthegvconductiongvpat
hway,gvDysrhythmiasgvofgvthisgvtypegvaregvnotgvlethal,gvAccessorygvpathwaygv(angvadditio
nalgvelectricalgvconductiongvpathwaygvb/
wgv2gvpartsgvofgvthegvheart;gvmaygvaltergvelectricalgvconductiongvsystemgvofgvthegvheart)
PrematuregvAtrialgvContractionsgv(PAC)gvInformationgv-gvANS--
EarlygvectopicgvbeatgvthatgvoriginatesgvoutsidegvthegvSAgvnode,gvCauses=gvatriagvbecom
esgvhypergvandgvfiregvearlygvcausedgvbygvmedications,gvcaffeine,gvtobacco,gvhypoxia,gvorg
vheartgvdisease,gvAdversegveffects=gvifgvfreqgvcangvbegvagvsigngvofgvimpendinggvheartgvfai
luregvorgvatrialgvtachycardiagvorgvfibrillation,gvTx=gv02,gvomitgvcaffeine,gvtobaccogvorgvothe
rgvstimulants.gvGivegvdigitalisgvorgvquinidine,gvtreatgvheartgvfailure
PrematuregvAtrialgvContractionsgv(PAC)gvfeaturesgv-gvANS--
Normalgvrate,gvusuallygvregulargvingvrhythmgvexceptgvforgvPAC,gvPgvwavesgvshapedgvdiffe
rentlygvfromgvagvnormalgvPgvwavegvorgvhiddengvingvprecedinggvTgvwavegv(PgvandgvTgvfireg
vatgvsamegvtime),gvPRgvintervalgv=gv0.12-
0.20gvsec,gvQRS=gv0.12gvsec,gvProducegvangvirregularitygvingvthegvrhythmgv(P-PgvandgvP-
RgvintervalsgvaregvshortergvthangvthegvP-PgvandgvR-
Rgvintervalsgvofgvunderlyinggvrhythm),gvHavegvPgvwavesgvthatgvaregvuprightgv(ingvleadgvII)g
INTERPRETATION QUESTIONS AND
ANSWERS
GeneralgvRulesgv-gvANS--
Firstgvandgvmostgvimportant,gvlookgvatgvyourgvpatient.gvReadgvleftgvtogvright.gvApplygvthegv
systematicgvapproach.gvAvoidgvshortcutsgvandgvassumptions.gvAskgvandgvanswergveachg
vquestiongvingvthegvECGgvanalysisgvapproach.
ECGgvRhythmgvAnalysisgv-gvANS--
AnalyzegvPgvwavesgv(Pgvwavegvisgvpresent,gvshapegvisgvconsistent,gvmustgvbegvbeforegve
achgvQRS),gvAnalyzegvQRSgvcomplexgv(presentgvandgvconsistent),gvDeterminegvatrialgvr
hythmgvorgvregularitygv(assessinggvP-PgvintervalgvorgvR-
Rgvinterval),gvDeterminegvventriculargvrhythmgvorgvregularitygv(assessinggvR-
Rgvinterval),gvDeterminegvHeartgvRate,gvMeasuregvthegvPRgvintervalgv(measurementgvsh
ouldgvbegvconstantgvandgvshouldgvbegvbetweengv0.12-
0.20gvsec),gvMeasuregvthegvQRSgvdurationgv(measurementgvshouldgvbegvconstantgvandgv
shouldgvbegvbetweengv0.04-0.10gvsec),gvinterpretgvthegvrhythm
Artifactsgv-gvANS--Wave-formsgvoutsidegvthegvheart-interference.gvCausedgvby:
gvPatentgvmovement,gvloosegvorgvdefectivegvelectrodes,gvimpropergvgrounding,gvfaultygvE
CGgvapparatus.
SinusgvRhythmsgv-gvANS--
Normal,gvSinusgvBradycardia,gvSinusgvTachycardia,gvSinusgvArrhytmia,
NormalgvSinusgvRhythmsgv-gvANS--
SAgvnodegvgeneratesgvimpulsegvthatgvfollowedgvagvnormalgvpathway.gvheartgvrategvfallgvw
ithingv60-
100gvBPM,gvatrialgvandgvventriculargvrhythmsgvaregvnormal,gvpgvwavegvprecedesgveverygv
QRS,gvPRgvintervalgvisgvwithingv0.12-0.20,gvQRSgvisgvwithingv0.12gvseconds.
AtrialgvRhythmsgv-gvANS--
AtrialgvDysrhythmias,gvPrematuregvAtrialgvContractionsgv(PAC),gvAtrialgvTachycardiagv(un
ifocal,gvmultifocal),gvAtrialgvFlutter,gvAtrialgvFibrillation
SinusgvBradycardiagvfeaturesgv-gvANS--
SAgvnodegvfiresgvslowergvthangvnormalgvHRgv(<60gvbpm),gvrhythmgvisgvregular,gvPgvwave
gvuprightgvandgvsamegvshape,gvPRgvisgvconstantgv0.12-0.20,gvQRSgv-normalgv<0.12gvsec
SinusgvBradycardiagvinformationgv-gvANS--
Causes:gvvagalgvstimulation,gvMI,gvHypoxia,gvDigitalisgvtoxicitygv(herbalgvmeds),gvMedicat
, iongvsidegveffects,gvnormalgvtogvelitegvaerobicallygvfitgvathletesgv(pumpsgvmoregvblood/
beat)
Adversegveffects:gvDizziness,gvweakness,gvsyncope,gvdiaphoresis,gvpallor,gvhypotension
Treatment:gvAccordinggvtogvsymptoms,gvatropinegvtogvspeedgvupgvheartgvrate,gvpacemak
er
SinusgvTachycardiagvfeaturesgv-gvANS--
SAgvnodegvfiresgvatgvagvrategvfastergvthangvnormal,gv>100gvbpmgvbutgvconductiongvpathw
aygvisgvnormal.gvAllgvcriteriagvforgvinterpretationgvaregvthegvsamegvexceptgvthatgvthegvheart
gvrategvisgvfaster.
SinusgvTachycardiagvinformationgv-gvANS--
Causes:gvemotionallygvupset,gvpain,gvfever,gvthyrotoxicosisgv(hyperthyroid),gvhypoxia,gvh
ypovolemia,gvinhibitiongvofgvvagusgvnervegv(parasympathetic)
Adversegveffects:gvAngina,gvdizziness,gvhypotension,gvincreasedgvingvcardiacgvworkloadg
v
Treatment:gvTreatgvthegvcause,gvmedicationsgvmaygvbegvgivengv(b-blockers)
SinusgvArrhythmiagv-gvANS--
Thegvonlygvirregulargvrhythmgvfromgvthegvsinusgvnodegvandgvhasgvagvcyclicgvpatterngvthatg
vusuallygvcorrespondsgvwithgvbreathing,gvRate=gvvariesgvwithgvrespiratorygvpattern,gvReg
ularity=gvirregulargvingvagvrepetitivegvpattern,gvPgvwave=gvuprightgvingvmostgvleads,gvsame
gvshapegvandgvonegvtogveachgvQRS;P-
Pgvintervalgvisgvirregular,gvQRS=gv<0.12,gvCause=gvusuallygvbreathinggvpatterngvbutgvcan
gvalsogvbegvheartgvdisease,gvTx=gvUsuallygvnongvrequired
AtrialgvDysrhythmiasgv-gvANS--
SAgvnodegvfailsgvtogvgenerategvangvimpulsegv(atrialgvtissuegvtakesgvover),gvAtrialgvnodesgv
orgvinternodalgvpathwaysgvmaygvinitiategvangvimpulsegvandgvfollowsgvthegvconductiongvpat
hway,gvDysrhythmiasgvofgvthisgvtypegvaregvnotgvlethal,gvAccessorygvpathwaygv(angvadditio
nalgvelectricalgvconductiongvpathwaygvb/
wgv2gvpartsgvofgvthegvheart;gvmaygvaltergvelectricalgvconductiongvsystemgvofgvthegvheart)
PrematuregvAtrialgvContractionsgv(PAC)gvInformationgv-gvANS--
EarlygvectopicgvbeatgvthatgvoriginatesgvoutsidegvthegvSAgvnode,gvCauses=gvatriagvbecom
esgvhypergvandgvfiregvearlygvcausedgvbygvmedications,gvcaffeine,gvtobacco,gvhypoxia,gvorg
vheartgvdisease,gvAdversegveffects=gvifgvfreqgvcangvbegvagvsigngvofgvimpendinggvheartgvfai
luregvorgvatrialgvtachycardiagvorgvfibrillation,gvTx=gv02,gvomitgvcaffeine,gvtobaccogvorgvothe
rgvstimulants.gvGivegvdigitalisgvorgvquinidine,gvtreatgvheartgvfailure
PrematuregvAtrialgvContractionsgv(PAC)gvfeaturesgv-gvANS--
Normalgvrate,gvusuallygvregulargvingvrhythmgvexceptgvforgvPAC,gvPgvwavesgvshapedgvdiffe
rentlygvfromgvagvnormalgvPgvwavegvorgvhiddengvingvprecedinggvTgvwavegv(PgvandgvTgvfireg
vatgvsamegvtime),gvPRgvintervalgv=gv0.12-
0.20gvsec,gvQRS=gv0.12gvsec,gvProducegvangvirregularitygvingvthegvrhythmgv(P-PgvandgvP-
RgvintervalsgvaregvshortergvthangvthegvP-PgvandgvR-
Rgvintervalsgvofgvunderlyinggvrhythm),gvHavegvPgvwavesgvthatgvaregvuprightgv(ingvleadgvII)g
