Cardiac exercise testing

Types of test

• 6 minute walk test
  • Test goal: measure distance walked in 6 minutes with or without assistive device
  • Rationale: test for endurance related to cardiovascular health
  • Setting used: Phase I and Phase II of cardiac rehabilitation
  • Test advantages: Quick assessment of endurance that can be completed for lower level patients
• Graded exercise testing
  • Test goal: assess the maximal workload that can be applied to the cardiovascular system via treadmill testing at different grades (incline)
  • Rationale: provide therapist with information on highest capacity of exercise tolerance
    • Provides maximal heart rate that can be used to then give target heart range with activity
  • Setting: Phase II cardiac rehabilitation
  • Test advantages: Most accurate assessment tool of an individual’s exercise tolerance
• Cycler ergometer test:
  • Test goal: submaximal test utilized to assess the VO₂ max through graded exercise (increasing in resistance)
  • Rational: provide VO₂ max information that can then be placed in equation to calculate maximal heart rate
  • Setting: Phase II cardiac rehabilitation
  • Test advantage: Utilized over maximal exercise testing if patient unable to tolerate maximal testing parameters

Definitions

Maximal exercise test

Exercise testing in which the highest resistance, highest level of intensity, and longest duration an individual can tolerate.

Submaximal exercise test

Exercise testing that has limits to not exceed a pre-established threshold to not allow for highest intensity or highest resistance capable by patient; utilize the VO₂ max number and input into equation to quantify the individuals maximal heart rate

VO₂ max

Maximum rate of oxygen that can be used in exercise; used specifically in submaximal exercise testing to quantify activity tolerance

Contraindications for exercise testing

• Unstable angina
• Acute myocardial infarction
• Acute congestive heart failure
• Uncontrolled arrhythmias
• Systolic blood pressure >200 mmHg or diastolic blood pressure >115 mmHg
• Severe anemia
• Hemoglobin less than 8
• Advanced or complicated pregnancy

Reasons to stop exercise testing

• Severe ST segment depression of 2mm or greater
• Cardiac arrest
• Development of new 2nd or 3rd degree heart block
• Patient requests to stop
• Severe chest pain, dizziness, or dyspnea
• Fall in systolic blood pressure <20 mmHg
• Ataxia
• Rise in systolic blood pressure >200 mmHg or diastolic > 110 mm Hg

Cardiac medications

• Beta blockers (atenolol): hypertension medication
  • Mechanism of action: works on the heart muscle by blocking epinephrine and causing vasodilators
  • PT implications: do not use heart rate as indicator for response to exercise; use perceived exertion scale (RPE) to assist with tolerance to activity
• Calcium channel blockers: hypertension medication
  • Mechanism of action: works on heart muscle to prevent calcium from entering heart tissue; decreasing contractility
  • PT implications: orthostatic hypotension
• Angiotensin converting enzyme inhibitors (ACE Inhibitors): hypertension medications
  • Mechanism of action: works on kidneys to stop the conversion of Angiotensin I to converting to Angiotensin II and causes vasodilation in peripheral vascular system
  • PT implications: Orthostatic hypotension, dizziness, palpitations
• Diuretics (lasix & hydrochlorothiazide): hypertension medication
  • Mechanism of action: works on kidneys to decrease the fluid retention in body by moving sodium out of the body
  • PT implications: electrolyte imbalance, orthostatic hypotension, muscle cramps,
    increased urination
• Anticoagulants (warfarin, coumadin): decreases clotting of blood
  • Mechanism of action: works to reduce the clotting within blood
  • PT implications: hemorrhage risk, can easily bruise
• Nitroglycerin: used specifically for angina pectoralis
  • Mechanism of action: work to relax smooth muscle in the heart by release of nitric oxide which will cause vasodilation and reduction in blood pressure
    • Specifically used in angina pectoris
  • PT implications: dizziness, headache, weakness, nausea
• Digitalis (digoxin): congestive heart failure medication
  • Mechanism of action: inhibits AV node activation
  • PT implications: decreased renal failure, increased risk for toxicity (digoxin toxicity) which can lead to hospitalization
• Antihyperlipidemias (statins): cholesterol mediation
  • Mechanism of action: blocks production of cholesterol by liver
  • PT implications: muscle pain, muscle weakness, fatigue, diarrhea, constipation, headache
• Amiodorone (antiarrhythmic agent): unstable ventricular tachycardia and recurrent ventricular fibrillation medication
  • Mechanism of action: increases the duration of the action potential as well as the effective refractory period for cardiac cells
  • PT implications: signs of congestive heart failure, including dyspnea, rales/crackles, peripheral edema, jugular venous distention, and exercise intolerance

Observational cardiac topics

Pulse (also known as heart beat or rhythm)

• 0= absent
• 1+ = weak/thready
• 2+= normal
• 3+= increased
• 4+= bounding

Pitting edema grading (associated with right sided heart failure):

• Grade 1: 0-2 mm indentation and rebounds immediately
• Grade 2: 3-4 mm indentation and rebounds within 15 seconds
• Grade 3: 5-6 mm indentation and rebounds within 30-60 seconds
• Grade 4: 8mm or more indentation and rebounds 60 seconds or longer

Auscultation of heart sounds

Image #7

• S1:
  • Normal heart sound
  • First heart sound when atrioventricular (mitral and tricuspid) valve close
  • Heard at the 5th intercostal space at midclavicular line
  • Signals the beginning of systole
  • Often referred to as “lub”
• S2
  • Normal heart sound
  • Second heart sound when semilunar (aortic and pulmonary) valves close
  • Heart at at the second intercostal space along the right sternal boarder
  • Signals the beginning of diastole
  • Often referred to as “dub”
• S3
  • Adventitious heart sound in adults and normal in children
  • Heard between 4th and 5th ribs on left side of chest
  • Associated with rapid filling of ventricles during early diastole
  • Often associated with fluid overload or weakened left ventricle which can be indicative heart failure, myocardial infarction, dilated cardiomyopathy, valvular regurgitation, or constrictive pericarditis
• S4
  • Adventitious heart sound in adults and children
  • Heard between 4th and 5th ribs on left or right side of chest
  • Associated with reduced ventricular compliance or increased resistance to ventricular filling
  • Often associated with left ventricular hypertrophy or left sided heart failure