Cardiac exercise testing

Types of test

• 6-minute walk test
  • Test goal: measure distance walked in 6 minutes with or without an 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 the therapist with information on the highest capacity of exercise tolerance
    • Provides the maximal heart rate that can be used to then give the target heart range with activity
  • Setting: Phase II cardiac rehabilitation
  • Test advantages: Most accurate assessment tool of an individual’s exercise tolerance
• Cycle ergometer test:
  • Test goal: submaximal test utilized to assess the VO₂ max through graded exercise (increasing in resistance)
  • Rationale: provide VO₂ max information that can then be placed in an equation to calculate maximal heart rate
  • Setting: Phase II cardiac rehabilitation
  • Test advantage: Utilized over maximal exercise testing if the patient is unable to tolerate maximal testing parameters

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; decreased heart rate
  • PT implications: do not use heart rate as an indicator for response to exercise; use the perceived exertion scale (RPE) to assist with tolerance to activity
• Calcium channel blockers: hypertension medication
  • Mechanism of action: works on the heart muscle to prevent calcium from entering heart tissue; increases vasodilation; decreases heart rate
  • PT implications: orthostatic hypotension
• Angiotensin converting enzyme inhibitors (ACE Inhibitors): hypertension medications
  • Mechanism of action: works on the kidneys to stop the conversion of Angiotensin I to converting to Angiotensin II and causes vasodilation in the peripheral vascular system
  • PT implications: Orthostatic hypotension, dizziness, palpitations
• Diuretics (lasix & hydrochlorothiazide): hypertension medication
  • Mechanism of action: works on the kidneys to decrease the fluid retention in the 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 the blood
  • PT implications: hemorrhage risk, can easily bruise
• Nitroglycerin: used specifically for angina pectoris
  • Mechanism of action: works to relax smooth muscle in the heart, releasing nitric oxide, which will cause vasodilation and a 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: increases renal failure, increased risk for toxicity (digoxin toxicity), which can lead to hospitalization
• Antihyperlipidemias (statins): cholesterol medication
  • Mechanism of action: blocks the production of cholesterol by the liver
  • PT implications: muscle pain, muscle weakness, fatigue, diarrhea, constipation, headache
• Amiodarone (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 heartbeat or rhythm)

• 0= absent
• 1+ = weak/thready
• 2+= diminished
• 3+= normal
• 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

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