NCLEX-RN Flashcards: Cardiac Nursing, Heart Failure, MI, ECG Rhythms, CPR

Classic signs of myocardial infarction, or heart attack, include substernal chest pain described as crushing, squeezing, or heaviness that may radiate to the left arm, jaw, neck, or back. Associated symptoms include diaphoresis, nausea, shortness of breath, and a sense of impending doom. Women, elderly patients, and diabetic patients may present atypically with fatigue, indigestion, back pain, or shortness of breath without classic chest pain.

Left-sided heart failure causes fluid to back up into the lungs, producing pulmonary symptoms. Key signs include dyspnea on exertion, orthopnea which is difficulty breathing when lying flat, paroxysmal nocturnal dyspnea where the patient wakes at night gasping for air, crackles or rales on lung auscultation, cough with frothy pink-tinged sputum in severe cases, fatigue, tachycardia, and S3 heart sound also called a ventricular gallop. Chest X-ray shows pulmonary congestion.

Right-sided heart failure causes fluid to back up into the systemic venous circulation, producing peripheral symptoms. Key signs include dependent peripheral edema starting in the ankles and feet, weight gain from fluid retention, jugular venous distention or distended neck veins, hepatomegaly which is an enlarged congested liver, ascites which is fluid accumulation in the abdomen, and elevated central venous pressure. Right-sided failure often results from chronic left-sided failure.

The current basic life support sequence for an unresponsive adult follows C-A-B: compressions, airway, breathing. First, confirm unresponsiveness and call for help. Activate the emergency response system and get a defibrillator. Begin chest compressions immediately: push hard and fast at a rate of 100 to 120 compressions per minute, at a depth of at least 2 inches, allowing full chest recoil. After 30 compressions, open the airway with head-tilt chin-lift and give 2 breaths. Continue the 30 to 2 cycle. When the defibrillator arrives, apply it immediately.

Normal sinus rhythm shows regular, evenly spaced QRS complexes with a consistent P wave before each QRS, a heart rate of 60 to 100 beats per minute, and a regular rhythm. Atrial fibrillation shows an irregularly irregular rhythm with no identifiable P waves, replaced by a chaotic fibrillatory baseline. The ventricular rate varies and can be rapid, normal, or slow depending on conduction through the AV node.

Digoxin toxicity occurs when serum digoxin levels exceed the narrow therapeutic range of 0.5 to 2.0 nanograms per milliliter. Early signs include gastrointestinal symptoms such as anorexia, nausea, and vomiting, and visual disturbances including blurred vision and seeing yellow-green halos around lights. Cardiac signs include bradycardia, premature ventricular contractions, and heart block. Hypokalemia increases the risk of toxicity because digoxin and potassium compete for the same binding sites on the heart muscle.

Troponin is a protein found in cardiac muscle cells that is released into the bloodstream when heart muscle is damaged. It is the most sensitive and specific biomarker for myocardial infarction. Troponin I and troponin T are the two forms tested. Levels begin rising within two to four hours of cardiac injury, peak at 12 to 24 hours, and remain elevated for 7 to 14 days. A positive troponin in a patient with chest pain confirms myocardial injury. Serial troponin levels are drawn at presentation and repeated at three to six hour intervals to detect a rising pattern that confirms acute MI.

After cardiac catheterization, assess the access site, usually the femoral or radial artery, for bleeding, hematoma formation, and signs of pseudoaneurysm. Check distal pulses, sensation, temperature, and color of the affected extremity to detect arterial occlusion. Monitor vital signs frequently, especially blood pressure and heart rate. Maintain the affected extremity straight and immobile for the prescribed time if femoral access was used. Encourage fluid intake to flush contrast dye and prevent nephropathy. ---