Page 1 Cardiovascular Study Guide for the CCRN®
On the CCRN® test, you will see that about 18% of the questions concern making decisions about cardiovascular issues while in a critical care nursing position. The questions all begin with a scenario and you’ll need to rely on a vast amount of knowledge about not only the anatomy of the cardiovascular system but also what to do if things aren’t functioning properly and methods of addressing emergency situations in this realm. This study guide will review the basics that will be assessed on the test.
Acute Coronary Syndromes
Acute coronary syndromes occur in the event that blood flow is lost, intermittently or permanently, causing cardiac muscle damage, ischemia, and injury. There are several types of acute coronary syndrome. Please review these diagnoses, risk factors, prevention strategies, and therapies:
Stable angina is chest pain that occurs with stress or exercise and is a result of decreased blood flow through the heart. Symptoms include dyspnea, diaphoresis, dizziness, fatigue, nausea, and anxiety. It can be diagnosed by angiogram and by performing a stress test. Risk factors for stable angina include diabetes, high blood pressure, hyperlipidemia, sedentary lifestyle, smoking, older age, and male gender. This type of angina is relieved by rest and/or nitroglycerin. Medications and/or lifestyle changes to manage the underlying chronic conditions/risk factors should also be considered.
Also called preinfarction or crescendo angina, unstable angina is chest pain that occurs both at rest and with exertion. The pain gradually worsens and becomes more frequent, eventually leading to a myocardial infarction (heart attack). Symptoms of unstable angina are the same as stable angina. Risk factors include diabetes, obesity, family history, hypertension, hyperlipidemia, male gender, smoking history, and an inactive lifestyle. Age is also a risk factor. Men over the age of 45 and women over the age of 55 are more at risk for unstable angina. Diagnosis can be completed with lab work (creatine kinase, troponin, etc.), electrocardiogram (ECG), echocardiography (echo), and CT angiography (CTA). Treatment includes eliminating or reducing the blockage, antiplatelet therapy (heparin, Lovenox®, warfarin, clopidogrel, etc.), and medications to treat any underlying chronic conditions. Lifestyle changes, including a low-sodium diet, lowering stress, increasing exercise, losing weight (if overweight), and stopping smoking, are also recommended.
Also known as Prinzmetal’s angina, variant angina occurs at rest and rarely with exertion and is a result of epicardial coronary artery spasm. It usually happens in the night or early morning hours. Diagnosis is confirmed with ergonovine or acetylcholine administration during angiography. This helps to visualize the active spasm. ST-segment elevation on ECG may occur during the spasms. Treatment of this condition is with calcium channel blockers and nitroglycerin. Beta-blockers may exacerbate spasm and should be avoided. Prognosis with treatment is good.
Non-ST Segment Elevation Myocardial Infarction (NSTEMI)
Please see section on Acute Myocardial Infarction/Ischemia for more information.
ST segment elevation myocardial infarction (STEMI)
Please see section on Acute Myocardial Infarction/Ischemia for more information.
Acute Myocardial Infarction/Ischemia
Acute myocardial infarction/ischemia (MI) is commonly known as a heart attack. MIs occur due to the blockage of blood flow through some of the heart, resulting in death of the cardiac muscles.
Causes and Symptoms
This may be due to either embolus or vasospasm. While previous cardiovascular disease may have been identified, many patients have no prior cardiac history. Common symptoms of acute MI include pain to the neck or arms, palpitations, hypertension or hypotension, pulmonary edema, nausea, vomiting, diaphoresis, neurologic disturbances, visual changes, speech changes, and feelings of dread or doom.
Early diagnosis is key to implementing life-saving measures. Electrocardiogram (ECG) tracings may identify T-wave inversion, elevated ST segments, abnormal Q waves, tachycardia, bradycardia, or dysrhythmias. An echocardiogram may be used to assess ventricular function and identify any concerns in blood flow/perfusion. Numerous blood tests should also be performed. The following are the most commonly drawn labs after a MI:
Troponin levels— increase 3 to 6 hours after infarct, peak at 14 to 20 hours, and are elevated for 1 to 2 weeks.
Creatine kinase (CK-MB)— increases 4 to 8 hours after injury and peaks at 24 hours (earlier with thrombolytic therapy).
Ischemia modified albumin (IMA)— increases in minutes, peaks at 6 hours, and returns to baseline.
Myoglobin— increases in 30 minutes to 4 hours, peaks at 6 to 7 hours, and a failure to increase can be used to rule out MI.
Two Types of MI
There are also two common classifications of MI, Non-ST elevation MI (NSTEMI) and ST elevation MI (STEMI). In the event on NSTEMI, circulation is reduced and not completely blocked. Changes on ECG show a depressed ST wave or T-wave inversion with no progression to Q wave. There will be a partial blockage of the coronary artery noted on cardiac catheterization. In some events, a cardiac stent will be placed to support the vessel and in others, balloon angioplasty may be performed to compress the plaques and reduce the blocked area. STEMI events occur when a blockage occurs, limiting or stopping blood circulation to the cardiac muscle. The ECG will show an elevated ST wave with progression to the Q wave. There will be full blockage of the coronary artery and, depending on the density of the blockage, either a cardiac stent or cardiac bypass surgery will be performed to restore circulation to the distal tissues.
Locations of MI
The most common locations for MI, either STEMI or NSTEMI, are in the left ventricle and septum. However, occlusions can occur in other coronary vessels that may result in right ventricular ischemia. Nurses should understand the association between vessel occlusion and resulting infarct location. Also note which leads to monitor for ECG changes in that patient.
- Anterior infarct
- Vessel: Proximal left anterior descending (LAD) or left coronary artery
- Facing ECG changes: leads \(V_2\) to \(V_4\)
- Reciprocal ECG changes: II, III, \(_aV_F\)
- Lateral infarct
- Vessel: Circumflex coronary artery or branch of left coronary artery
- Facing ECG changes: leads I, \(_aVL\), \(V_5\), \(V_6\)
- Reciprocal ECG changes: leads II, III, \(_aV_F\)
- Inferior/diaphragmatic infarct
- Vessel: Right coronary artery
- Facing ECG changes: leads II, III, \(_aV_F\)
- Reciprocal ECG changes: leads I and \(_aVL\)
- Right ventricular
- Vessel: Proximal section of right coronary artery
- Facing ECG changes: \(V_4R\), \(V_5R\), \(V_6R\)
- Reciprocal ECG changes: none to possible ST elevation in \(V_1\)
- Vessel: Right coronary artery or circumflex artery
- Facing ECG changes: leads \(V_1 - V_4\)
- Reciprocal ECG changes: leads \(V_1−V_4\)
Treatment for MI
Treatment for acute MI may take several forms. Depending on the degree and location of the blockage, MI symptoms may be treated with cardiac catheterization, vessel stenting, and medication. Open heart surgery, bypass procedure, and extended infusions are also treatment options if previous methods do not adequately restore circulation.
Fibrinolytic infusions may be indicated if symptoms of MI have been occurring for less than 12 hours, have greater than or equal to 1mm elevation of ST tracing in greater than two contiguous leads, and have no contraindications or cardiogenic shock. The earlier the administration of these agents, the better the outcome. Common medications include first-generation fibrinolytics streptokinase and anistreplase, second-generation alteplase or tissue plasminogen activator (tPA), and third-generation reteplase and tenecteplase.
Contraindications to fibrinolytic therapy include history of severe bleeding, intracranial hemorrhage, history of stroke, aortic dissection, pericarditis, recent (<3 months) spinal or cranial surgery, neoplasm, aneurysm, or AVM. High caution should be used in patients with active peptic ulcer, renal or hepatic disease, pregnancy, anticoagulation therapy, uncontrolled hypertension, recent (in past 2 to 4 weeks) internal bleeding, and greater than 10 minutes of CPR.
Continual monitoring of labs and need for continued fibrinolytic therapy should be performed. In the event of cardiac surgery or catheterization, follow post-operative recommendations to prevent bleeding, monitor for hemorrhage, and other potential complications.
Papillary Muscle Rupture
Papillary muscle rupture is a rare but deadly complication of myocardial infarction. Responsible for the movement of the tricuspid and mitral valves, these muscles prevent blood regurgitation and valve prolapse. When ruptured, the muscles can no longer prevent the backflow of blood through the heart, which can result in cardiogenic shock.
Symptoms of this condition include acute heart failure, pulmonary edema, tachycardia, diaphoresis, loss of consciousness, pallor, tachypnea, mental status change, weak/thready pulse, and decreased urinary output.
Diagnosis can be achieved with transesophageal echocardiography (TEE) used to visualize the papillary muscles. Color flow doppler and echocardiogram can help identify the flow and severity of the valve prolapse/regurgitation within the heart. Nurses must be aware of any new holosystolic murmurs noted from the apex radiating to the axilla. Emergent surgical repair of the affected valve is indicated when diagnosed to prevent further cardiac damage and death.
Anticoagulants help to prevent clot formation. Patients are often prescribed these medications in response to or prevention of thromboembolism, MI, or stroke. Nurses should monitor for increased risk of bleeding for patients on these medications. Prior to invasive procedures, patients may be asked to stop this medication for a specific amount of time.
Aspirin: prophylaxis; do not give to children or adolescents as it poses an increased risk of Reye’s syndrome
Warfarin (Coumadin®): blocks the body’s uptake of vitamin K; patients need routine blood work to monitor for anticoagulant effects; antidote to overdose is vitamin K administration
Heparin: primarily used for IV anticoagulation; monitored labs include aPTT or AntiXa; monitor for adverse reaction of heparin induced thrombocytopenia (HIT); antidote to overdose is protamine sulfate.
Dalteparin (Fragmin®) and Enoxaparin (Lovenox®): used in DVT prophylaxis, unstable angina, MI, and cardiac surgery
Bivalirudin (Angiomax®): used for prophylaxis and in the event of HIT