Stress testing Physiology: Sympathetic system activation increases: Heart rate Stroke volume Cardiac output Ventricular contractility Afterload (Vasoconstriction) Muscular & Coronary flow (Vasodilatation)

Demand vs. Supply Coronary flow Oxygen consumption (VO 2 ) Resting VO 2 = 1 Mets = 3,5 ml O 2 / min / kg.

Exercise tests Master test BicycleTreadmill ECG - 3 leads (V5), 12 leads Computerized ST analysis Treadmill stress test

Positive stress test Anginal pain or dyspnea ST↓ horizontal >1 mm 0.08” after J point ST↓ downsloping > 0.5 mm ST↓ upsloping > 1.5 mm ST↑ elevation QRS widening

Exercise test accuracy Sensitivity =% of pts. w. CAD & ETT(+) ~ 66 % Specificity = % of normals with ETT(-) ~77 % False negative: borderline lesions, collaterals False positive: LVH, MVP, digitalis, LBBB

Indications for ETT I. Diagnostic – probability of CAD Evaluation of symptoms: chest pain, dyspnea, fatigue Evaluation of symptoms: chest pain, dyspnea, fatigue Asymptomatic – Multiple CAD risk factor Asymptomatic – Multiple CAD risk factor Screening Screening Functional Capacity Functional Capacity Detection of Arrthymia and response to Rx Detection of Arrthymia and response to Rx Hypertensive response Hypertensive response

II. Prognostic: Known CAD – risk stratification Stable AP, or worsening AP, DOE, FC Before and after revascularization (PTCA, CABG) Pre operative risk evaluation Indications for ETT

III. Post Acute Coronary Syndrome Need for revascularization Medical treatment adjustment (AP, BP, HR, Arrhythmias) (AP, BP, HR, Arrhythmias) Guide for cardiac rehabilitation, Self-confidence Timing of return to work and its intensity Indications for ETT

High risk ETT > 4 % Mortality risk Low F.C. < 6 min exercise ST depression at low HR or stress ST depression > 2 mm ST elevation or QRS widening Severe AP or dyspnea Arrhythmias (VT, PAF) Systolic BP drop

Contraindications for ETT Risk < 0.01 %, Post MI 0.03% Unstable Angina Acute Heart Failure Arrhythmias Myo- or Peri-carditis Severe Aortic Stenosis Hypertrophic obstructive cardiomyopathy Severe Hypertension (>220/110 mmHg)

Exercise testing Fasting, off β-blockers Symptom limited: AP, dyspnea, dizziness, fatigue, leg pain AP, dyspnea, dizziness, fatigue, leg pain Max. heart rate = 220 – age Target heart rate: 85 % of max. HR If not achieved – non diagnostic test If not achieved – non diagnostic test Stop if: ST↓ > 3 mm, ST↑, SBP↓ > 10mmHg, technical problems with ECG monitoring

Nuclear Cardiology Myocardial perfusion Thallium – 201 Cyclotron product: dose - 2 mCurie Long half life – 72 hours 85% - first pass myocardial uptake Na-K-ATPase pump Redistribution: 4 or 24 hr.= viability

LAO view of the heart (pathology) S RV PW A LV

Thallium image during angina

Thallium - planar views of the heart

Thallium Treadmill stress test

Severe exercise – induced ischemia Multiple defects, lung uptake, LV dilatation

Thalium 201 Diagnosis Infarct: Perfusion defect at stress and rest Ischemia: Defect at stress that normalizes after 4 or 24 hours. Sensitivity ~ 90 % Specificity ~ 80 % Localization of ischemia / infarct Extend and severity of CAD Functional vs. anatomic assessment (angio) Planar vs. spect (tomographic) imaging

Normal Myocardial Perfusion

Myocardial Ischemia

Myocardial Infarction

Technetium Sestamibi Higher dose (30 mCurie), improved image quality Shorter half life (6 hours) No redistribution, therefore 2 separate injections for rest and stress ECG gating for wall motion, EF First pass imaging

Pharmacologic vs. stress imaging Indicated for pts. unable to complete full stress test due to low HR, PVD, COPD, CHF, orthopedic disability Adenosin or dypiridamole drip: vasodilatation of normal vs. narrowed coronaries of normal vs. narrowed coronaries Thallium or Tech. sestamibi injection Perfusion abnormality similar to stress

Contrast left ventricular angiography: Antero – apical aneurysm RAO view Diastole Systole

Technetium 99 labeled RBC First pass image or at equilibrium Multigated acquisition (MUGA) Regional wall motion at rest and / or stress Ejection Fraction (%)= X 100 Assessment of ischemia Viability: Dobutamine effect m EDC - ESC EDC

ECG – gated acquisition

MUGA – RAO view

MUGA – LAO view RV LV DiastoleSystole RVLV

MUGA – bicycle exercise

Gated Cardiac Results

Indications for nuclear testing I.Diagnostic CAD assessment – best for intermediate likelihood of CAD CAD assessment – best for intermediate likelihood of CAD Extent and severity of CAD Extent and severity of CAD Extent of ischemic vs. infarcted areas Extent of ischemic vs. infarcted areas Need for revascularization Need for revascularization

II. Prognostic: Risk stratification - MI / Death: 0.5 – 50 % for normal vs. high risk scan Pre-operative assessment Post ACS / MI Change in symptoms / ETT results Indications for nuclear testing

High risk nuclear test Multiple and / or severe perfusion defects Increased lung uptake Stress induced LV dilatation

III. Viability study (hybernating vs. scar tissue) Thallium late redistribution MUGA with dobutamine drip Positron emission tomography (PET) Mismatch between reduced perfusion (ammonia or rubidium) and preserved metabolism (glucose) Mismatch between reduced perfusion (ammonia or rubidium) and preserved metabolism (glucose) Improved function following revascularization Indications for nuclear testing

PET Scan: Viability study