Diagnostic test

Blood Studies

Essential Blood Tests

  • Electrolytes ( some electrolytes cause dysrhythmias)

  • Glucose & Hemoglobin A1C → diabetes is a risk factor for MI

  • Sedimentation Rate (SED Rate) → inflammatory markers

  • Complete Blood Count (CBC) → blood transfusion

  • Blood Coagulation Tests → prevent clotting formation

  • Blood Urea Nitrogen (BUN) and Creatinine → UTI

  • Urinalysis → UTI

  • C-Reactive Protein (CRP)

Lab Values: Cardiac Biomarkers

Important Cardiac Biomarkers

  • Troponin T (cTnT) & Troponin I (cTnI): Assess cardiac muscle damage. Rises in 4-6 hours, peaks 10-24 hours, detectable for 10-14 days. Can elevate with renal failure.

  • Creatine Kinase (CK):

    • CK-MB: Cardiac specific isoenzyme. Rises in 3-6 hours, peaks 12-24 hours, returns to baseline in 12-48 hours.

    • Note: Copeptin and myoglobin are not observed locally.

  • Graphical Representation: Figure 33-10 depicts Troponin, CK-MB, and Myoglobin increase over time.

Additional Blood Studies

  • C-Reactive Protein (CRP): Marker for inflammation, linked to atherosclerosis.

  • Homocysteine: Elevated levels increase risk for CVAD, PVD, and stroke.

  • Cardiac Natriuretic Peptide Markers: Elevated B-type Natriuretic Peptide (BNP) indicates heart failure. (ANP, C-type NP also exist).

  • Serum Lipids: Triglycerides, LDLs are key markers.

Radiological Tests

Types of Imaging Studies

  • Chest X-Ray

  • Fluoroscopy

  • Echocardiography (Echo/TEE)

  • CT Scan (Multi-dimensional CT)

  • MRI/CMRI/MRA

Echocardiogram

  • Ultrasound of the heart, assesses structure and motion, measures ejection fraction (EF). Includes stress echo or TEE.

Nuclear Cardiology Testing

  • Techniques like MUGA scan, stress perfusion imaging. IV medications may simulate exercise effects. Types include SPECT and PET stress testing.

Exercise or Stress Testing

  • Evaluates cardiac vascular response to physical activity. EKG recorded during exercise (treadmill/pedal bike) to monitor heart's response to increased workload. Protocols vary.

Diagnostic Studies of Cardiovascular System

  • Cardiac Catheterization:

    • Right-sided: Measures heart pressures.

    • Left-sided: Evaluates coronary arteries (coronary angiography) using contrast to identify blockages. Provides info on cardiac diseases. Involves mild sedation and post-procedure care.

  • Intravascular Ultrasound: Performed during coronary angiography.

  • Fractional Flow Reserve: Uses a special wire to measure pressure and flow in coronary arteries.

  • Electrophysiology Study (EPS): Determines origin of unexplained dysrhythmias (e.g., atrial fibrillation/flutter, SVT). Minimally invasive, uses electrodes in heart to record electrical activity, induce dysrhythmias, and apply medications/ablation for rectification.

Audience Response Example

  • A patient returns to the cardiac observation area following a cardiac catheterization with coronary angiography. Which assessment would require immediate action by the nurse?

    • a. Pedal pulses: 2+ bilaterally

    • b. Apical pulse: 54 beats/minute

    • c. Mean arterial pressure: 72 mm Hg

    • d. ST-segment elevation develops on the ECG