Introduction to Advanced Introduction to Advanced Cardiopulmonry Cardiopulmonry

RehabilitationRehabilitation

PED 596

Spring 2002

Review Physiological Review Physiological Responses to ExerciseResponses to Exercise

Exercise is Homeostatic Emergency

Acute = AccommodateAcute = AccommodateImmediate response to an “Exercise Emergency”GOAL: Maintain homeostasis

Chronic = AdaptChronic = AdaptRepeated exposures to “Exercise Emergencies” stimulate adaptive changes

Training Effects

Define “Exercise”Define “Exercise”You should get more “exercise!”

Muscular activity (work)Induces increased oxygen uptakeIncreased cardiac outputIncreased cellular energy metabolism

WORK CAPACITY and THE PHYSIOLOGICAL RESPONSE TO WORK

Bottom Line - Emergency #1Bottom Line - Emergency #1: : Exercise Demands: ATP supply Exercise Demands: ATP supply and substrate delivery systemsand substrate delivery systems

ATP Supply: Fuel Supply: Glucose, Fatty Acids

Oxygen Supply

Metabolic Machinery: Rate Regulating Enzymes

Delivery System: Cardiopulmonary Systems

Bottom Line - Emergency #2Bottom Line - Emergency #2: : Exercise Demands: Better Exercise Demands: Better machinerymachinery

Work Output is an “external” product of exerciseWork Capacity is in part determined by Muscle strengthMuscle Strength: Function of cross-section and neurological efficiency

AdaptationAdaptation: Improves the ability : Improves the ability to respond to each “Homeostatic to respond to each “Homeostatic

Emergency” Emergency”

Specificity of Training: Specificity of Training:

Peripheral Adaptations: Muscle Fiber: Protein synthesis, metabolic enzymes, mitochondrial density, glycogen, triglyceride and myoglobin storesAngiogenesis

Central Adaptations:Cardiovascular: Cardiac output, peripheral resistance, blood volume, RBC, ventilatory threshold, insulin sensitivity

Exercise Testing: Clinical Exercise Testing: Clinical

Clinical Indications for Clinical Indications for Exercise Testing:Exercise Testing:

Diagnosis: Reproduce symptomsCP, SOB, Poor work toleranceECG changes?

Functional Testing:Work Capacity, BP response to exercise, Exercise duration

Prognosis:AHA, AACVPR, ACP: Risk Stratification, Duke’s 5-Year Mortality prognosis

Diagnosis:Diagnosis:

Indications:Confirm or rule out suspected myocardial ischemia

Mechanisms for syncope (LOC)

Suspected arrhythmias (palpitations with symptoms) during exercise

Functional Capacity:Functional Capacity:Indications:

Assessing work capacity for return to work/leisure activites

Used in determining risk/prognostic stratification

Used in determining therapy choices

Exercise Prescription: Phase II Entrance requirements

Prognostic BenchmarksPrognostic Benchmarks

<5 METs: poor prognosis especially under 65 years old

10 METs: considered normal fitness: survival good – regardless of intervention

13 METs: good prognosis even with CAD present

BikeBike vs. vs. TreadmillTreadmill

Less expensive

Less space

Quieter

Less ECG artifact

Easier BP’s

Non-Weight dependent

More flexibility in protocolsMore reproducible (not-patient dependent)More accurate work determinations

Specificity of Testing:Specificity of Testing:

Patient Preference / Experience

Diagnostic Protocols:

To Elicit Symptoms

Often quit at ~80% predicted HR Max

Critical Measurements:Critical Measurements:

Work Loads: MET calculations

ECG: Clean ST-Segment changes

BP: Accurate work SBP/DBP

RPP: MVO2 eliciting CP

Elicited Symptoms: CP, SOB, Syncope

Myocardial O2 demand (MVO2) depends on..

Myocardial tension (pressure x volume)

Inotropic State (Measure?)

Chronotropic state (Measure?)

Myocardial mass

Indirect measure of MVO2Indirect measure of MVO2

Rate pressure product (a.k.a. double product, tension-time index)

Considers 2 of the MVO2 indices:

HR X SBP

Good estimate of oxygen use by the heart.

Used to determine angina threshold

12-Lead ECG: Electrode 12-Lead ECG: Electrode PlacementPlacement

RA/LA: On Shoulders at distal ends of clavicles: (Not over large muscle masses)

RL/LL:Base of Torso: Just medial to the iliac crests

Chest Leads: V1-V6Traditional precordial positioning

V1-V2: 4th intercostal space –R/L of sternumV4: 5th intercostal space – midclavicle lineV3: Between V2 and V4V5: At horizontal level of V4, anterior to axillaV6: Midaxillary at horizontal level of V4

Treadmill Protocols:Treadmill Protocols:Treadmill Speed: IndividualizeIncrement Size: Age, condition

Larger incremental increases for younger, more fit patientsSmaller incremental increases for elderly, de-conditioned

Test Length: Between 8-12 minutes

Estimating Work Capacity: Estimating Work Capacity: Selecting ProtocolsSelecting Protocols

Healthy Men >40 years old75% have 12.5 MET capacity

50% ~ 10 METs

Healthy Women >40 years old75% have 10 MET capacity

50% ~8-9 METs

Choose a protocol that achieves the estimated MET capacity between 8-12 minutes

Commonly Used Clinical Commonly Used Clinical Protocols: Protocols:

Naughton: 2.0 mph X 3.5% increases every 2 minutes

Max METs = 9 /16 minutes

Balke: 3.3 mph X 3% increases every 3 minutes

Max METs = 12 /18 minutes

McHenry: Similar to Balke but Stage I is 2.0 mph/3% grade

Measurements: HR, BP, Measurements: HR, BP, ECGECGPre-Test: Supine and Exercise Position

Exercise: HR/BP in final minute of each stage – ECG every minute and whenever irregularities appear

Post-Test: Immediately post exercise and every 1-2 minutes until full recovery

Measurements: RPE, Measurements: RPE, SymptomsSymptoms

RPE: In the last minute of each stage

Symptoms: Note symptoms that occur:

Ask frequently, “How are you feeling?”

Rating Anginal Symptoms: Rating Anginal Symptoms:

1+: Light, barely noticeable

2+: Moderate, bothersome

3+: Severe, very uncomfortable

4+: Most severe pain ever experienced

Post Exercise Period: Post Exercise Period: For Maximal Diagnostic Sensitivity:

No Cool Down10-sec ECG immediately 6-8 minutes of supine monitoring* - record ECG every minute or after any irregularity

*Unless patient is severely dyspneic – then sitting preferred

Testing Competencies: Testing Competencies:

Know Absolute and Relative indications for test termination:

3+ to 4+ angina

Suspected MI

Drop in SBP with increased work

Serious arrhythmias

Signs of poor perfusion

Patient request

Exercise Test Endpoints:Exercise Test Endpoints:

Pre-determined HR achieved

Pre-determined Workload achieved

Patient c/o CP, SOB, leg pains, fatigue

ECG changes:Significant ST changes

New Bundle branch or AV block

Increasing PVC frequency, VT or Fib

A Little Diagnostic A Little Diagnostic InteractionInteraction

HHMI Cardiology Lab

Cardiovascular Cardiovascular PharmacologyPharmacology

Exercise Implications

Understanding the Role of Understanding the Role of Medications in Exercise:Medications in Exercise:

What is the physiological response to exercise?

What is the mechanism of action of the drug?

Is there individual variability?

How are generalities best applied to exercise testing and prescription?

Cardiovascular Response to Cardiovascular Response to Exercise: Acute / Chronic Exercise: Acute / Chronic

Changes in Autonomic Nervous System

SNS: Acute responses

PSNS: Resting status in trained persons

Cardiovascular Changes:HR, BP, myocardial contractility, venous return, vascular resistance,

Therefore: Therefore:

Any drug that acts on the autonomic nervous system, heart, blood vessels or kidneys may impact exercise

Drug Classifications: Drug Classifications: Mechanism: Mechanism: Use: Use:

Diuretics:

ACE Inhibitors

Beta-blockers

Ca++ Channel blockers

Nitrates

Anti-hypertensiveAnti-hypertensive, CHF, Anti-hypertensive, tachycardiasAnti-hypertensive, tachycardiasAnti-anginal

Diuretics: Diuretics:

Alter renal reabsorption or secretion of H2O and/or Na+

Increase diuresis

Used for Hypertension and CHF

May cause electrolyte imbalances: especially K+

Commonly Used Diuretics:Commonly Used Diuretics:

Thiazide Diuretics: Diuril, (Lozol)

Loop Diuretics: Lasix, Bumex, Edecrin

K+ Sparing: Aldactone, Dyazide

Effects of Diuretics on Effects of Diuretics on Exercise: (See ACSM)Exercise: (See ACSM)

Very little effect except for decreased blood pressure

CAUTION: May cause PVC’s or false + ischemia signs with electrolyte imbalances

ACE Inhibitors: ACE Inhibitors: Inhibits Renin-Angiotensin Aldosterone (RAA) System:

Renin is released from kidneys in response to hypotension/ Na+

Renin increases levels of Angiotensin I (liver)Angiotensin Converting Enzyme (ACE) converts Ang I to Angiotensin II (active)

What Does Angiotensin II Do?What Does Angiotensin II Do?

Vasoconstriction Blood Pressure

Increase H2O and N+

Retention

Stimulate release of ADH and Aldosterone

Net Effect: Increase Blood Pressure

Therapeutic Uses of ACE Therapeutic Uses of ACE Inhibitors: Inhibitors:

Hypertension: Improved diuresis, vascular relaxationCHF: The combined effect of diuresis, vascular relaxation reduces Pre/After-Loads on heart

* Affects diuresis without direct action on kidneys – can be used in patients with impaired kidney function

Commonly Used ACE Commonly Used ACE Inhibitors:Inhibitors:

Captopril (Capoten): Used in mild to moderate hypertension

Vasotec, Lotensisn: Used in all hypertensions and CHF

Zestril, Prinivil: Once a day dosing

Effects of ACE Inhibitors on Effects of ACE Inhibitors on Exercise: Exercise:

Little effect except to decrease blood pressure

May actually improve exercise capacity in patients with CHF

Beta-Blockers: Beta-Blockers: Beta-adrenoceptor antagonist:

Reduces SNS stimulation of Beta-receptorsProlongs AV conduction ( HR)Inhibit Phase 4 DepolarizationDecrease Contractility

Decreases MVO2

Contraindicated: CHF*, asthma, diabetes

Therapeutic Uses Of Beta-Therapeutic Uses Of Beta-Blockers:Blockers:

Used for treating mild to moderate hypertension

Treating Angina

Reducing tachyarrhythmias

Commonly Used Beta-Commonly Used Beta-Blockers:Blockers:

InderalLopressorCorgardBlocadrenTenormimLopressor

Effect of Beta-Blockers on Effect of Beta-Blockers on Exercise:Exercise:

Reduced resting and exercise HR/BP

Reduced ischemia

Exercise capacity equivocal: may decrease in patients without angina

Calcium Channel Blockers:Calcium Channel Blockers:

Block slow calcium channels in myocardial and vascular smooth muscle cells:

Reduce vasoconstriction

Decrease cardiac contractility

Decrease MVO2

Can lead to AV-Block

Therapeutic Uses of Calcium Therapeutic Uses of Calcium Channel Blockers:Channel Blockers:

Treatment of Hypertension

Tachyarrhythmias

Cautious use in CHF

Commonly Used Calcium Commonly Used Calcium Channel Blockers: Channel Blockers:

Verapamil: Calan, Verelan

Diltiazem: Cardizem

Nifedipine: Procardia

Nicardipine: Cardene

Effects of Calcium Channel Effects of Calcium Channel Blockers on Exercise:Blockers on Exercise:

Check ACSM Manual

Variable Effects on Heart Rate

Blood Pressure

Exercise Capacity

Nitrates:Nitrates:

Dilates all blood vessels

Relieves symptoms of angina:Vasodilation decreases cardiac pre-load and MVO2

Fast acting

Short lived effects

Nitroglycerine:Nitroglycerine:

Generally used for immediate relief of anginaSublingual: also Isordil, SorbitrateAdverse Effects:

Orthostatic hypotensionHeadache, reflex tachycardiaExcesses can produce methemoglobin - hemolysis

Exercise and Nitrates:Exercise and Nitrates:

Increase HR

Decrease BP

Increase exercsie capacity for those with angina