Cardiovascular System Assessment, Diagnostic Tests, and Lab Tests Practicum

A & P Review

Layers of the Heart

Conduction

Conduction Rate SA Node: times a minute AV Node: times a minute Bundle of His: times a minute AV Node and Bundle of His are often referred to as AV junction or just the junction and all above considered supraventricular rhythms.

Conduction Rates If all supraventricular pacer nodes fail, the right and left bundle branches and Purkinje fibers will attempt to pace the ventricles at a rate times a minute. Essentially the ventricles will try to pace themselves.

Assessment First and most important assessment skill is listening to your patient. Listen to what they are complaining of (pain, dizziness, swelling, etc). Take a complete history. Include previous medical problems, surgery, family history, smoking, medications. Review any previous charts and prescriptions.

Inspection Look at your patient closely….WITH YOUR OWN EYES. You may see something someone else missed. Look at lifts, pulsations, neck vein distention, skin color, nail beds, scars, medical ID bracelets, swelling, facial expression, body position.

Vital Signs Pulse A. Regularity B. Rate (Too fast? Too slow?) C. Strength (bounding, strong, weak, thready, absent. *If too weak or unable to palpate, use a doppler.

Doppler

Point of maximal impulse (PMI)

PMI

Blood Pressure

Measured with a sphygmomanometer. Cuff is inflated until pressure is sufficient to stop blood flow, then is slowly released and the person taking the reading uses a stethoscope to listen at the pulse point. The first time a sound is heard a reading is recorded. This is systole which is the sound of the ventricle contracting. The sound gets progressively louder and then a change occurs from loud to soft. That change is recorded at the diastolic pressure (when the ventricles relax and the heart fills.

Blood Pressure Normal Adult Blood Pressure is considered 120/80 mm Hg. the stress resulting from the elongation of an elastic body Tension is the stress resulting from the elongation or stretching of an elastic body (artery wall). Normotension: Normal blood pressure. Hypotensive: Abnormally low blood pressure. Hypertensive: Abnormally high blood pressure.

Orthostatic (Postural) Hypotension A person who experiences a drop in blood pressure (greater than 20mm Hg systolic or 10mm Hg diastolic) when the person stands up from a sitting position.

Orthostatic Hypotension Normal when a person stands, gravity causes the blood to pool in the person’s legs and decrease the circulating volume. Baroreceptors near the heart and neck respond to the drop in blood pressure by speeding up the heart rate or vasoconstricting the blood vessels. Causes might be damage to the receptors (Parkinson’s or diabetes), heart problems, or low circulating volume (dehydration). Treatment: Sit down, get up slowly, TED hose, treat underlying cause. Nursing considerations: YOU MIGHT WANT TO SET THE BED ALARM FOR THESE PATIENTS and also place them on fall precautions. Frequent monitoring of these patients.

Auscultation

The act of listen to sounds arising within the body (usually with a stethoscope). From the latin word auscultation which means the act of listening. Auris means ear.

Auricle: External Ear

Auricle of the heart

Auricles Right has been associated with tachycardias. Left has been correlated with atrial fibrillation and blood clots. The left is a reservoir for the left atrium.

Auscultation Bell of stethoscope is better for hearing high pitched sounds like S1 and S2. (Lub-Dub). S1 is closure of mitral and tricuspid valves and ventricular contraction. S2 is closure of pulmonic and aortic valves.

Heart

Electrocardiogram (ECG or EKG) Recording of patient’s heart rhythm. Continuous monitoring in hospitals is called telemetry (electronic transmission of data-tele/o means distant). In acute care areas (ICU, ED, OR, PACU) patients are placed on continuous heart monitors at the bedside. A Holter monitor is an ECG device that is worn during a 24-hour period to detect rhythm changes and symptoms are recorded in a diary.

5 lead

12 lead

12 ECG Machine

24 Hour Holter Monitor

Stress Test Patient is placed on continuous ecg monitoring and put on treadmill and monitors heart’s response to exertion (stress).

Telemetry (Tele)

Echocardiography (ECHO) Echoes generated by high-frequency sound waves produce images of the heart. Shows movements and structures of the heart as well as blood flow and abnormalities.

Doppler Ultrasound Studies Sound waves measure movement of blood flow. Echoes bounce off red blood cells. The examiner can hear various alterations in blood flow caused by vessel obstruction. Used to detect carotid artery occlusion, aneurysms, varicose veins, blood clots.

Angiography X-ray imaging of blood vessels after injection of contrast material.

Computerized Tomography Angiography (CTA) Three-dimensional x-ray images of the heart and coronary arteries using computed tomography (CT). This new technology take 192 images of the heart per second. Cross-sectional images are assembled into 3D picture. Less invasive than angiography.

Cardiac Catheterization A thin, flexible tube is guided into the heart via a vein or an artery. This procedure detects pressures and patterns of blood flow in the heart. Contrast may be injected and x-ray images taken of the heart and blood vessels.

CXR A radiology image of the chest (basically a picture). Generally done from 2 views (back and side).

Abnormal CXR

Laboratory Tests Cardiac Enzymes Lipid Panels BNP

Cardiac Enzymes Cardiac enzymes are proteins from heart muscle cells that are released into the bloodstream when heart muscle is damaged, such as during a myocardial infarction (MI). By measuring blood levels of cardiac enzymes, doctors can tell whether heart muscle damage has recently occurred. Usually three sets of CE are drawn about every six hours. Cardiac enzymes include CK, CK-MB, Troponin.

Lipid Panels Measurement of fats and lipoproteins (fats and protein combo) to help determine the risk of coronary heart disease. Includes total cholesterol, LDL (low-density lipoprotein) “bad”, HDL (high-density lipoprotein) “good”, and triglyceride.

BNP (brain natriuretic peptide) Measure the amount of BNP hormone in your blood. It is secreted when the heart becomes overloaded. It acts as a diuretic to help the heart function return to normal. It is seen in patients with heart failure (CHF, cardiac arrest, etc).