EXERCISE ECG

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EXERCISE ECG

• NON CORONARY APPLICATIONS

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EXERCISE PHYSIOLOGY

• Vagal withdrawl-increase HR
• Symp activation-increase venous return
• -increase ventilation
• -incr HR
• Increase CO
• Increase BP-b/c of incr CO,though SVR fall

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At fixed work load ltAT,steady state of HR,CO,BP
and Ventilation occur in 2 mts.Hemodynamics
return to normal within mts on stopping
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V O2 MAX

• O2 consumption of body during max response to
  exercise
• Depends on-Efficiency of lungs, heart,circulatory
  system and peripheral tissue to extract O2
• Reproducible value,when corrected for Body wt

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V O2 MAX

• Can be asessed in many ways
• V O2 CO x ( CaO2_ Cv O2)
• Can be predicted from population values based on
  body wt
• From CP Ex test, breath by breath analysis of PA
  O2 and PI O2
• VO2VxWx(.073OC/100) x 1.8

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ANAEROBIC THRESHOLD

• Point when muscle switch to anaerobic metabolism
  as an additional source
• Lactate accumulate CO2
• V CO2 increase, so VE incr
• AT occur at 40-60 of VO2 Max

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AT

• AT can be identified by
• disproportionate rise inVCO2
• disproportionate rise in VE
• disproportionate rise in ratio of Vco2/Vo2
  to Vo2
• Point of intersection of VO2 and VCO2 slopes

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Noncoronary indications

• CLASS I
• Evaluation of Ex capacity response to Rx in
  CHF pts for transplant
• Differentiate cardiac Vs pulm cause of DOE
• Chr AR,-to asess functional status in pts with
  equivocal symptoms
• Evaluate Ex capacty n child with CHD/Post op CHD,
  Valvular/myocardial diseases

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Class I

• Child with angina
• Appropriate setting in rate adaptive pacemakers
• Evaluation of cong CHB in children planning more
  physical activity/plan to participate in sports

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ClassIIa Indications

• Asymptomatic DM ,who plan to start vigorous
  physical activity
• Chr AR-evaluation of symptom and functional
  capacity before participating in sports
• Chr AR-prognostic asessment before AVR in
  minimally symptomatic with LV dysfn

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ClassIIa

• Exercise induced arrhythmia
• Evaluation of medical/surgical/RFA in pts with Ex
  induced arrhythmia
• Evaluation of Ex capacity for medical reasons in
  pts in whom subjective asessment is not reliable

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Valvular heart disease

• Objective asessment of atypical symptom
• Asess Ex capacity disability
• Elderly-asymptomatic b/c of inactivity
• For coexisting CAD

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Aortic StenosisSymptomatic sevAS is absolute CI
for TMT
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AS

• Elderly-asympt b/c of inactivity
• Cong AS
• Lesseffort tolerance,hypotension,ST
• depression,increased LVET-sev obstruction
• To diff pts with sev AS and Lvdysfn from pts with
  poor LV function in the setting of mild to mod
  AS-if trans Ao flow increse with Ex ,primary
  problem is LVdysfn

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AS

• Tst to be stopped if Hypotension,VPC,decrease HR
  occurs
• If BP response is abnormal ,pt require a cool
  down period before attaining supine position, to
  avoid volume overload.
• Ex ST depression.gt2mm is asso with gt50mm gradient
  in children

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AS

• STdepression not correlate with CAD
• Supravalvular AS increase BP in Rt UL

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AR

• ClassI indication in pts with equivocal symptoms
• gt1mm ST depression is asso with lower rest and Ex
  EF,increased wall stress, and greater ESV
• Decrease in HR, AT and MVO2 predict LV dysfn

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Mitral stenosis

• Useful in pts asymptomatic due to inactivity
• Abnormal increase in HR, decrease in BP ,chest
  pain are indicators for early surgery

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Mitral regurgitation

• Ex and asessing LV function post Ex is useful in
  documenting occult LV dysfn
• MVP without MR- Ex induced MR is asso with
  subsequent development of MR
• ST depression can occur in MVP-causes are pap
  muscle ischaemia,abnormal coronaries,compression
  of LAD,spasm,primarycardiomyopathy etc

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MR

• In pts with CAD undergoing TMT,development of
  ischaemic MR may be a cause for flat response in
  syst BP

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Pulmonary stenosis

• Decrease Ex capacity
• ST depression in inf and V1-V3
• May develop cyanosis with Ex,-shunt via PFO

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Congenital and Paediatric Uses

• Class IIb indications
• F/H of SCD
• Followup of diseases like Kawasakis
  disease,SLE etc where coronary disease are
  expected
• Long QT syndromes
• Asessment of VT in pts with cong CHB

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Class IIb indications

• Adequacy of Beta Blocker Rx in children
• Evaluation of BP response arm leg gradient
  after surgery for Co A.
• Asess degree of desaturation in well balanced or
  palliated cyanotic heart disease

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LEFT-RIGHT SHUNTS

• Usually no role
• Older pts show reduced Ex tolerance
• TMT not routinely done to decide operability
• Post Ex SaO2lt92PaO2lt80 correlate with PVRgt7

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Eisenmenger syndrome

• Ex is hazardous. Not routinely done
• TMT may be done to evaluate response to therapies
  intented to decrease PAH

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TOF

• Before Sx,they have,reduced Ex tolerance
  ,lessVO2,low peak HR,and Ex induced arrhythmia
• Post Sx,improvement in Ex capacity occurs
• TMT can be used to asess surgical efficacy and to
  detect residual lesion
• Reduced Ex capacity post Sx suggest residual
  lesion

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TOF

• If Ex test shows ST depression,less MaxVO2, poor
  Ex tolerance,ventricular arrhythmia pt should be
  evaluated for residual lesion/RV dysfn

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Other cyanotic heart diseases

• TMT is useful in detecting residual lesion, and
  ventricular arrhythmia post Sx
• Post switch Sx, to asess coronary insufficiency

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Coarctation

• After Sx ,abnormal syst BP elevation may occur
  normally with Ex
• Abnormal dia BP elevation suggest restenosis
• Rest A-L Gradientgt15 and Ex gradientgt35 require
  angioplasty/Sx
• Significant ST depression also suggest
  significant gradient29

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Children with CAD

• Ex test is indicated in the following pts prior
  to participating in sports programme and
  evaluation of chest pain in them
• ALCAPA,Kawasakis disease,SLE,Coronary aneurysm,
  post switch Sx,post TOF Sx with RCA crossing
  RVOT close to infundibular resection

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Supra ventricular arrhythmia

• Atrial ectopics if ectopic has Stdepression more
  than sinus beat or has tall R than sinus beat it
  suggest CAD
• AF- To detect whether rate is controlled even
  with Ex
• Stdepression in AF s/o CAD

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Sick sinus syndrome

• To differentiate b/w sss and vagotonia
• Chronotropic incompetence s/oSSS(in ability to
  attain 85 MPHR
• Can also occur in severe CAD with LV dysfn

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Ventricular tachycardia

• VT may be reproducible with Ex
• Varies from 36-80
• RVOT VT reliably reproduced
• Also has prognostic value
• Also useful in asessing efficacy of Rx

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Congenital CHB

• Indi cated in child with CHB
• If they have effort intolerance PPI
• Also useful in evaluating syncope in them.can
  demonsrate Torsades

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Bundle branch blocks

• Rate related BBB-usually occur in asso with CAD
• RBBB-reliability of ST depression is debated
• ST depression may occur in V1-V3 without CAD
• ST depression in V4-V6 s/o CAD

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LBBB

• Usually not possible to diagnose CAD in presence
  of LBBB with TMT
• Stdepression more than 1.5mm than at rest s/o CAD

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WPW SYNDROME

• ST depression does not indicate CAD
• Ex may bring out delta wave
• Ex can cause disappearance of delta wave
• Abrupt loss of pre excitation indicate larger
  refractory period in accessory pathway,.
• These pts are unlikely to develop rapid
  ventricular rate with atrial arrhythmia

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LQTS

• QTc.440 msec 1mt after Ex s/o LQTS

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CHF-Severity

• AVO2gt20,ATgt8
• BVO2-16-20,AT 6-8
• CVO2- 10-16,AT 4-6
• DVO2 lt10 ,ATlt4

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Timing of transplant

• Pts who achieve gt50 predicted Max VO2
  ,transplant may be defered
• Peak VO2gt14ml/mt/kg?transplant can be deferred

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Evaluation of DOE

• Cardiac ?VE Max does not exceed 50 of MVV
• VO2 Max and AT achieved usually
• SaO2does not fall below 90

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Resp DOE

• VEMax exceeds gt50 of MVV
• VO2 Max and AT not achieved
• Hypoxia occurs

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