EXERCISE ECG NON CORONARY APPLICATIONS EXERCISE PHYSIOLOGY Vagal

EXERCISE ECG NON CORONARY APPLICATIONS

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

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

V O 2 MAX O 2 consumption of body during max response to exercise n Depends on-Efficiency of lungs, heart, circulatory system and peripheral tissue to extract O 2 n Reproducible value, when corrected for Body wt n

V O 2 MAX Can be asessed in many ways n V O 2= CO x ( Ca. O 2_ Cv O 2) n Can be predicted from population values based on body wt n From CP Ex test, breath by breath analysis of PA O 2 and PI O 2 n VO 2=Vx. Wx(. 073+OC/100) x 1. 8 n

ANAEROBIC THRESHOLD Point when muscle switch to anaerobic metabolism as an additional source n Lactate accumulate –CO 2 n V CO 2 increase, so VE incr n AT occur at 40 -60% of VO 2 Max n

AT AT can be identified by n disproportionate rise in. VCO 2 n disproportionate rise in VE n disproportionate rise in ratio of Vco 2/Vo 2 to Vo 2 n Point of intersection of VO 2 and VCO 2 slopes n

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

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

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

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

Valvular heart disease Objective asessment of atypical symptom n Asess Ex capacity &disability n Elderly-asymptomatic b/c of inactivity n For coexisting CAD n

Aortic Stenosis Symptomatic sev. AS is absolute CI for TMT

AS Elderly-asympt b/c of inactivity n Cong AS n Lesseffort tolerance, hypotension, ST n depression, increased LVET-sev obstruction n 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 n

AS Tst to be stopped if Hypotension, VPC, decrease HR occurs n If BP response is abnormal , pt require a cool down period before attaining supine position, to avoid volume overload. n Ex ST depression. >2 mm is asso with >50 mm gradient in children n

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

AR Class. I indication in pts with equivocal symptoms n >1 mm ST depression is asso with lower rest and Ex EF, increased wall stress, and greater ESV n Decrease in HR, AT and MVO 2 predict LV dysfn n

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

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

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

Pulmonary stenosis Decrease Ex capacity n ST depression in inf and V 1 -V 3 n May develop cyanosis with Ex, -shunt via PFO n

Congenital and Paediatric Uses Class IIb indications n F/H of SCD n Followup of diseases like Kawasaki’s disease, SLE etc where coronary disease are expected n Long QT syndromes n Asessment of VT in pts with cong CHB n

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

LEFT-RIGHT SHUNTS Usually no role n Older pts show reduced Ex tolerance n TMT not routinely done to decide operability n Post Ex Sa. O 2<92%&Pa. O 2<80% correlate with PVR>7 n

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

TOF Before Sx, they have, reduced Ex tolerance , less. VO 2, low peak HR, and Ex induced arrhythmia n Post Sx, improvement in Ex capacity occurs n TMT can be used to asess surgical efficacy and to detect residual lesion n Reduced Ex capacity post Sx suggest residual lesion n

TOF n If Ex test shows ST depression, less Max. VO 2, poor Ex tolerance, ventricular arrhythmia pt should be evaluated for residual lesion/RV dysfn

Other cyanotic heart diseases TMT is useful in detecting residual lesion, and ventricular arrhythmia post Sx n Post switch Sx, to asess coronary insufficiency n

Coarctation After Sx , abnormal syst BP elevation may occur normally with Ex n Abnormal dia BP elevation suggest restenosis n Rest A-L Gradient>15 and Ex gradient>35 require angioplasty/Sx n Significant ST depression also suggest significant gradient 29 n

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

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

Sick sinus syndrome To differentiate b/w sss and vagotonia n Chronotropic incompetence s/o. SSS(in – ability to attain 85% MPHR n Can also occur in severe CAD with LV dysfn n

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

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

Bundle branch blocks Rate related BBB-usually occur in asso with CAD n RBBB-reliability of ST depression is debated n ST depression may occur in V 1 -V 3 without CAD n ST depression in V 4 -V 6 s/o CAD n

LBBB Usually not possible to diagnose CAD in presence of LBBB with TMT n Stdepression more than 1. 5 mm than at rest s/o CAD n

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

LQTS n QTc. 440 msec 1 mt after Ex s/o LQTS

CHF-Severity A—VO 2>20, AT>8 n B—VO 2 -16 -20, AT 6 -8 n C—VO 2 - 10 -16, AT 4 -6 n D—VO 2 <10 , AT<4 n

Timing of transplant n Pts who achieve >50% predicted Max VO 2 , transplant may be defered n Peak VO 2>14 ml/mt/kg transplant can be deferred

Evaluation of DOE Cardiac VE Max does not exceed 50% of MVV n VO 2 Max and AT achieved usually n Sa. O 2 does not fall below 90% n

Resp DOE n VEMax exceeds >50% of MVV n VO 2 Max and AT not achieved n Hypoxia occurs