Cardiovascular Study Guide for the CCRN

Cardiac Trauma

Cardiac trauma can occur due to blunt force or penetration injury. Trauma may cause outcomes ranging from resolving arrhythmias to imminent death.

The most common cause of blunt force trauma is motor vehicle accidents. Motor vehicle accidents can result in crush, compression, or deceleration injuries to the heart. Blunt cardiac trauma can also be caused by sports-related injuries.

Penetration of the cardiac muscle is most often related to stab or gunshot wounds. Penetration injuries can also be secondary to medical procedures such as central line placement, thoracic surgery, chest tube placement, and pericardiocentesis.

Treatment of cardiac trauma involves preventing further injury to the cardiac muscle, stopping any bleeding, and alleviating any pressure on the cardiac muscle. Patients should be monitored closely for arrhythmias, bleeding, pericarditis, and cardiac tamponade.

Cardiac/Vascular Catheterization

Cardiac catheterization is both a diagnostic and interventional procedure when vascular occlusion is suspected. Nurses must understand the indications for each type of catheterization as well as any interventions to perform postoperatively.

Diagnostic

In diagnostic cardiac catheterization, a catheter is inserted in an artery or vein in the groin, neck, or arm (large vessel) and threaded through blood vessels to the heart. The catheters can be used to assess for blockages and perform pressure measurements of the associated cardiac chambers and vessels. It can also be used to perform right or left ventriculogram and cardiac biopsy. A coronary angiogram is the catheterization of the coronary vessels to determine their perfusion and function. A right heart catheterization may be used to determine right-sided chamber pressures and blood flow. Congenital heart defects, such as septal defects, patent processes, and other cardiac anomalies, may also be diagnosed with cardiac catheterization.

Interventional

Interventional cardiac catheterization occurs in response to a cardiac event in which vessels are blocked or narrowed. It is frequently used as an alternative to open heart surgery. Common types of interventional cardiac catheterization include coronary angioplasty, coronary stenting, angioplasty with or without stent placement, fixing congenital defects, replacing or repairing valves, cardiac ablation, balloon valvuloplasty (open narrowed heart valves), and balloon angioplasty (open narrowed arteries in or near the heart).

Nursing Care

In the event of a patient undergoing cardiac catheterization, the nurse should anticipate interventions regarding preparation for and recovery from this procedure. Risk factors of cardiac catheterization include bleeding, heart attack, stroke, damage to the artery, arrhythmia, allergic reaction to contrast or medication, renal damage, infection, and clots. Post-surgical observation and assessment of the puncture site and dressing should be performed regularly. The dressing should not be prematurely removed and the nurse should monitor for clot dislodgement or internal bleeding (hematoma, ecchymosis), especially if the patient is coughing or vomiting. Generally, the dressing can be removed after 24 hours.

To help prevent internal or external bleeding from the puncture site, patients undergoing diagnostic cardiac catheterization are required to have strict bed rest and lie flat (no greater than 30-degree head of bed elevation) for four hours. If an interventional cardiac catheterization was performed, the patient’s bed rest and flat time increases to six hours.

Just as with any surgical procedure, postoperative nursing assessment should include monitoring for infection and thrombus formation. Frequent neurovascular checks to assess distal extremity circulation are also required. Retroperitoneal bleeding is a significant concern and may be indicated by fluctuating blood pressure response, bradycardia, hypotension, abdominal pain, groin and/or back pain, and diaphoresis. Other signs of bleeding include tachycardia, hypotension, decreased peripheral perfusion, increasing pulse pressure, agitation, and decreased hemoglobin.

Cardiogenic Shock

Cardiogenic shock occurs when the heart cannot pump enough blood for the needs of the body. It is most often caused by a severe myocardial infarction. It can also be caused by myo- and endocarditis, cardiomyopathy, and drug overdose/poisoning. Those at highest risk include older age, history of prior heart failure or myocardial infarction, coronary artery disease, diabetes, hypertension, and females. While rare, it is an extremely fatal condition if not treated promptly.

Symptoms

Symptoms of cardiogenic shock include severe shortness of breath, tachycardia, loss of consciousness, thready pulse, hypotension, diaphoresis, pallor, clammy hands and feet, and decreased urination. This condition is diagnosed by ECG changes, chest x-ray, echocardiogram, and cardiac catheterization (angiogram).

Treatment

Treatment medications include inotropic agents such as norepinephrine (Levophed®) or dopamine; aspirin; thrombolytics such as alteplase (Activase®) or reteplase (Retavase®); and antiplatelet medication such as clopidogrel (Plavix®), abciximab (Reopro®), tirofiban (Aggrastat®), and eptifibatide (Integrilin®). Understand the indication for these medications, side effects, and contraindications to administration.

In addition to pharmacologic support, the patient must be placed on oxygen and undergo therapy to restore blood flow to and through the heart. The patient may have to undergo angioplasty with stenting to remove and/or stent a blocked vessel, balloon pump to decrease the workload of the heart, and/or mechanical circulatory support such as extracorporeal membrane oxygenation (ECMO). If these measures fail to treat the shock, surgical measures such as coronary artery bypass surgery, ventricular assistive device (LVAD), and heart transplant may be considered.

Cardiomyopathies

Dilated Cardiomyopathy

Dilated cardiomyopathy (DCM) is characterized by an enlarged left ventricle limiting effective blood flow to the body. It is often caused by coronary artery disease, excessive alcohol intake, metabolic disease (thyroid, diabetes, etc.), viral infections, anatomic abnormalities (valve concerns), drugs (cocaine), and heavy metal poisoning (cobalt). The damaged cardiac muscle is replaced with scar tissue that then stimulates overgrowth of healthy cardiac cells. The overgrowth of the cardiac cells causes hypertrophy and muscle stretching. The muscle weakens, stresses the cardiac valves, and becomes ineffective in pumping blood.

Symptoms

Symptoms of DCM include dyspnea, shortness of breath, tachycardia, S3/S4 heart sounds, holosystolic murmur, wheezes/crackles, pleural effusions, edema, jugular vein distension (JVD), and ascites. ECG testing often shows tachycardia with T wave changes, cardiomegaly will be present on chest x-ray, and echocardiogram testing may show valve regurgitation and decreased ejection fraction.

Treatment

Treatment for dilated cardiomyopathy includes medications such as beta-blockers, ACE inhibitors, and diuretics. A low-sodium diet should also be implemented. Surgical interventions may include placement of a pacemaker, especially in light of cardiac dysrhythmia, and repair of the left ventricle. In severe cases, a heart transplant may be indicated.

Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy is a genetic disorder causing idiopathic thickening of the heart muscle, particularly the ventricular septum and left ventricle. Other characteristics of this disease include asymmetrical septum, forceful systole, cardiac dysrhythmias, and myocardial disarray. It may not be diagnosed until middle or late adulthood when symptoms become apparent.

Symptoms

Common symptoms of hypertrophic cardiomyopathy include exertional or atypical chest pain, dyspnea at rest, syncope, and palpitations. Diagnostic studies such as echocardiogram, ECG, x-ray, and a thorough family history can help to identify this condition.

Treatment

The primary treatment measure is a septal myectomy. While this has a higher mortality rate (3-10%), the outcome, when successful, increases cardiac output and quality of life. An alternate therapy is alcohol-based septal ablation, where ethanol 100% is injected into the heart, creating a controlled infarction and consequential thinning of the septum. Nurses must frequently assess these patients prior to and after treatment to monitor for significant changes in heart rate, blood pressure, and respiratory status.

Families should be educated on the genetic factor of this condition and educate them regarding the early signs, symptoms, and treatments to help identify and prevent extensive cardiac damage.

Idiopathic Cardiomyopathy

Idiopathic cardiomyopathy tends to occur in younger patients, 20 to 60 years old. Theories for this disease progression include overactive immune response (immune-mediated), toxic or metabolic injury, tachycardia-induced, viral, or inherited cause. A thorough family history, cardiac history, and any unusual recent changes in health should be documented. Treatment medications include ACE inhibitors, angiotensin II receptor antagonists, beta-blockers, diuretics, aldosterone antagonists, and digitalis.

Restrictive Cardiomyopathy

In restrictive cardiomyopathy, the ventricles stiffen due to the infiltration of fibroelastic tissues into the cardiac muscle. This decreases the compliance of the ventricles, thus decreasing the end-diastolic cardiac refill volume. Atrial enlargement occurs due to this resistance, which can lead to atrial fibrillation.

Symptoms

Symptoms of restrictive cardiomyopathy include exercise intolerance/fatigue, edema, crackles, elevated central venous pressure (CVP), S3/S4 heart sounds, cardiac murmur, and dyspnea at rest. It can be diagnosed with echocardiogram testing (showing an enlarged atria), hemodynamic monitoring (increased right atrial pressure, pulmonary wedge pressure, and systemic vascular resistance), x-ray, ECG, and cardiac biopsy. There may not be an identifying cause to the restrictive cardiomyopathy.

Treatment

Treatment plans include diuretics, calcium channel blockers, beta-blockers, ACE inhibitors, anticoagulants, lifestyle changes (low sodium), and even heart transplant in advanced cases.