Cardiology Diagnostic Tests

The speaker expresses enthusiasm for cardiology, indicating their long-standing passion for the subject.
Background:
- Graduated from the Indiana Certified College (ICC) years ago.
- Initially hesitant to take a job on the heart floor (2 West).
- Circumstances compelled the speaker to accept the job despite reservations.

Worked on 2 West and later with cardiologists:
- Spent years on the Heart Floor and in the cardiac clinic.
- There is a noted transition from being a nurse to teaching about cardiology for 20 years.
Encouragement for students to embrace the challenge of cardiology:
- They will either love or hate it, which affects their performance in the field.
- Emphasis on the complexity of the material and necessity of understanding it.

Importance of Diagnostics: - The heart cannot be seen or felt directly; thus, diagnostics are essential.
The heart is described as a single large muscle with blood vessels, focusing on:
- The coronary arteries:
- Three main arteries: right coronary artery, left main coronary artery, circumflex artery (circ), left anterior descending artery (LAD).
- These are crucial for supplying blood to the heart muscle.

Heart Attack Description:
- Defined as a complete blockage of a coronary artery.
- Plaque builds up, leading to platelet aggregation, and resulting in a clot.
- When tissue supplied by the blocked artery lacks blood supply, it dies.
- Symptoms: chest pain arises from dying muscle tissue not receiving adequate blood supply.
Enzymes and Biomarkers:
- Cardiac Biomarkers: - When muscle tissue dies, it releases enzymes detectable in the blood which helps diagnose a heart attack.
  - Creatine Kinase (CK): A general indicator of muscle damage that can elevate due to exercise, injections, or heart attacks.
  - CK-MB: A cardiac-specific isoenzyme of CK used to assess damage specifically related to the heart.
  - Elevates within hours of a heart attack, peaks at approximately 24 hours, and normalizes within 12-48 hours post-event.
  - Serial measurements over 12-24 hours are necessary to monitor levels.
- Troponin:
  - The most specific biomarker for diagnosing heart attacks.
  - Starts to elevate within hours and can remain elevated for 10 to 14 days.
  - Crucial for diagnosing delayed presentations of heart attacks (such as the hypothetical case of "Tiffany").
- Explanation using a scenario involving Tiffany and Jamie during a heart attack:
- Jamie presents with acute symptoms and elevated CK-MB and troponin.
- Tiffany presents days later and may only have elevated troponin due to the delayed nature of troponin release.

C-Reactive Protein (CRP):
- A marker for inflammation in the body indicating increased risk for heart attacks. Not typically used in the ER.
- Used for preventive screenings to assess patient risk levels.
Homocysteine:
- Another marker that indicates increased risk for coronary artery disease (CAD).
- Like CRP, used during routine check-ups, not emergencies.
B-Type Natriuretic Peptide (BNP):
- Used specifically to diagnose heart failure, with normal levels less than 100. Elevated levels indicate heart failure severity.

Understanding cholesterol is vital for assessing risk for coronary artery disease:
- Total Cholesterol: Ideally less than 200 (but only a starting point).
- Breakdown of total cholesterol into:
- LDL (Low-Density Lipoprotein): The “bad” cholesterol which should be less than 130; for those with CAD risk factors, even lower is preferred.
- HDL (High-Density Lipoprotein): The “good” cholesterol with a target of above 45-50.

Explanation of how high dietary intake (like fatty foods) as well as endogenous cholesterol production impacts cholesterol levels.

Importance of Potassium Levels:
- Essential for cardiac rhythm stability.
- Normal levels are between 3.5-5.0 mEq/L.
- Abnormal potassium levels (high or low) can trigger dysrhythmias and need careful monitoring during cardiac care.
BUN and Creatinine:
- Used to assess kidney function which can be affected by medications given to cardiac patients.

Types of EKGs:
- 12-Leads EKG:
- Real-time imaging, used during acute ER presentations to assess heart rhythm.
- Holter Monitor:
- Continuous monitoring for 24-48 hours to catch intermittent arrhythmias.
- Event Monitor:
- Long-term monitoring for suspected intermittent arrhythmias, can last up to 30 days.

Purpose:
- Assess heart response to physical stress; patients walk on a treadmill while monitored.
Technique:
- Gradual increases in speed/incline to reach target heart rate.
- EKG changes or symptoms of ischemia reveal potential blockages.
Beta Blocker Considerations:
- Beta-blockers should be held before tests to allow for maximal heart rate response.

X-rays: Used to assess structural heart changes, size, and function.
Echocardiography: Ultrasound imaging of cardiac structures; assesses heart function through ejection fraction.
CT Scans: Used to assess coronary arteries and various pathologies, often requiring beta-blockers to slow the heart down for clearer images.

Procedure:
- Diagnostic test injecting dye into heart vessels to identify blockages or issues.
Preparation:
- NPO, blood tests like BUN, creatinine, INR, potassium are critical.
Post Care:
- Monitoring for bleeding, assessing vital signs and pulses, especially at access sites.

Focuses on heart rhythms; similar nursing care as cardiac catheterizations:
- Asses vital signs, puncture sites, and rhythm stability post-procedure.

Summarize the overarching importance of diagnostics in cardiology and the student's role in mastering this information for their future practice in healthcare related to cardiology.