Stress testing Flashcards
Rest oxygen demand and blood flow
- low oxygen demand
- adequate blood flow
Stress oxygen demand and blood flow
- Increased oxygen demand and blood flow
Excercise stress testing meds to discontinue
Beta blockers: 72 hrs
Calcium channel blockers: 48 hrs
Long-acting nitrates: 12 hrs
Off caffeine: 24 hrs (varies by department)
Treadmill protocols
Bruce
Modified Bruce
Naughton
Reasons to terminate exercise
Chest Pain
ECG Changes
T wave inversion
ST segment depression >3 mm or elevation
Fatigue
HR & BP product target
METs
SOB
Syncope
Target HR achieved
Exercise contraindications
✔ Acute myocardial infarction (MI) (<2 days old)
✔ Unstable angina (chest pain at rest or worsening symptoms)
✔ Severe symptomatic aortic stenosis (risk of sudden collapse)
✔ Uncontrolled arrhythmias with hemodynamic instability
✔ Decompensated heart failure (fluid overload, respiratory distress)
✔ Acute myocarditis or pericarditis (risk of worsening inflammation)
✔ Severe pulmonary hypertension (right heart failure risk)
✔ Acute aortic dissection (risk of rupture and death)
✔ Active thromboembolic disease (e.g., pulmonary embolism, DVT
Exercise relative contraindications
⚠ Moderate valvular heart disease (e.g., moderate aortic stenosis or mitral stenosis)
⚠ Resting hypertension (>200/110 mmHg) (risk of hypertensive crisis)
⚠ Tachyarrhythmias or bradyarrhythmias (risk of instability)
⚠ High-degree AV block (e.g., Mobitz II, complete heart block)
⚠ Hypertrophic cardiomyopathy (HCM) with obstruction (risk of sudden cardiac death)
⚠ Severe electrolyte imbalances (e.g., hypokalemia, hypomagnesemia)
⚠ Recent stroke or TIA (<3 months) (risk of neurologic complications)
⚠ Uncontrolled diabetes with hyperglycemia (risk of metabolic crisis)
⚠ Physical disability limiting exercise (e.g., severe arthritis, neuromuscular disease)
What are the different pharmacological stress agents
Dipyridamole (Persantine)
Adenosine (Adenoscan)
Regadenoson (Lexiscan)
Coronary reserve
Dobutamine
Inotropic
Chronotropic
Advantages of pharmacologic stress tests
Standardized test
Pt’s unable to reach target HR:
- LBBB
- Pacemakers
- Respiratory conditions
- Limited HR response
Pt’s physically unable to stress
Pharmacologic stress disadvantages
No functional cardiac
information
Increased level of side effects
Pharmacologic contraindications
- allergies to dipyridamole and aminophylline
- Reactive airway diseases like asthma and COPD
Pharmacologic relative contraindications
Recent MI < 72hrs
Hypotension
Systolic pressure < 90mmHg
Refractive CHF
Unstable angina
Pharmacologic stress preparations
- NPO:4hrs
- No methylxanthines: 24hrs
- Caffeine/theophylline/nicotine
Persantine characteristics
Coronary vasodilator
Acts indirectly via adenosine
Increases coronary blood flow
HR increases ~13 bpm
T1/2 in serum ~30-60 min
Coronary peak ~6-8 min
Side effects:
Most common - chest pain & headaches
Persantine Dose
0.57 mg/kg, max 60mg
Infusion time persantine
continuous over 4 min
What is monitored during persantine?
- BP
- HR
- ECG
RP injected how long after persantine?
8 min
Persantine antidote
- aminophylline
- 50-100mg increments
Adenosine additional prep
- discontinue dipyridamole 12-24 hrs
Adenosine additional contraindications
- 2nd and 3rd degree heart block
- sinus node disease
Adenosine characteristics
Coronary vasodilator
Acts directly
Increases coronary blood flow
T1/2 in serum <10 sec
Coronary peak ~55 sec
Increased side effects
Adenosine dose
0.14 mg/kg/min
Adenosine infusion time
- continuous over 6min
