Doctor of Nursing Practice Portfoilio of Timothy S. Neilson

Atrial fibrillation (AF) is a relatively common arrhythmia encountered by the family nurse practitioner (FNP) in outpatient clinics, emergency departments, and inpatient units. The FNP must be able to gather a relevant history, perform a focused exam, and order appropriate diagnostic tests to accurately diagnose, classify, and treat the patient with AF. Current diagnostic and treatment strategies are discussed in this case study in the context of new onset AF in a 61 year-old woman. This patient was encountered in the emergency department of a rural hospital. The patient was subsequently followed on an outpatient basis with input from cardiology. The literature review for this case was conducted using CINAHL and Ovid databases, utilizing various combinations of the following keywords: atrial fibrillation, AF, underlying disease, evaluation, treatment, and CHADS2 (congestive heart failure, hypertension, age more than or equal to 75, diabetes mellitus, and stroke or transient ischemic attack history). Reference lists for the resulting articles were further explored for relevant research. ATRIAL FIBRILLATION 3 Introduction and Background Atrial fibrillation (AF) is a relatively common arrhythmia characterized by ineffective atrial contraction due to chaotic atrial depolarization (Patterson, Wolfe, & Bower, 2010). It is more prevalent in men and incidence rises in both sexes with increasing age (Go et al, 2001). Failure to diagnose and treat AF leads to a higher incidence of stroke due to the formation of atrial emboli that may become systemic (Aronow, 2008). In addition, adverse cardiac events may be increased due to a rapid ventricular response to AF. This can also lead to tachycardia-related cardiomyopathy (Aronow, 2008). Increased mortality rates in patients with untreated AF result from these higher incidences of cerebrovascular and cardiovascular events. The minimum evaluation of the patient with AF consists of a history, physical examination, specific laboratory diagnostics, and electrocardiogram (EKG), with echocardiogram after hemodynamic stabilization (Fuster, Ryden, & Cannom et al, 2006). Onset of symptoms, frequency and duration of symptoms, associated symptoms, and past treatment— as well as response—all contribute to the development of appropriate AF classification as outlined in Table 1 (Podrid, Zimetbaum, & Saperia, 2010). In addition, personal and family history can help the clinician determine if the AF could be secondary to an underlying disease process like diabetes or hypertension (Kannel, Wolf, Benjamin, & Levy, 1998). Gathering a social history is also important; those with a history of tobacco use have a higher incidence of AF (Kannel et al, 1998). ATRIAL FIBRILLATION 4 Table 1 AF Classification Paroxysmal Episodes terminate spontaneously in less than seven days, usually less than 24 hours. Persistent Episodes fail to spontaneously terminate in seven days, but may still do so. Cardioversion may be necessary. These patients often have paroxysmal events after initial conversion. Permanent Episode has lasted for more than one year; cardioversion has either been unsuccessful or not attempted. Lone Any type of AF that exists in patients with structural heart disease, usually applied to patients under 60 years of age. Appropriate diagnostics also assist in the classification and treatment of AF. Certain underlying physiologic conditions may be correctable and lead to resolution of AF. Serum studies, including complete blood count (CBC), comprehensive metabolic profile (CMP), thyroid stimulating hormone (TSH), and Troponin I are indicated. Inflammation and infection can contribute to the pathogenesis of AF (Ichiki, Orihara, & Hamasaki, 2009). Electrolyte imbalances can lead to a variety of dangerous arrhythmias, including AF (Nishimura, Nakayama, & Ishikawa, 1996). Untreated or undiagnosed hyperthyroidism can also cause AF (BieleckaDabrowa, Mikhailidis, Rysz, & Banach, 2009). In addition to laboratory tests, an EKG must be performed to evaluate the electrophysiology of the heart and an echocardiogram to assess the structural condition of the heart. Ischemic heart disease, congestive heart failure, pericarditis, and valvular disease are all examples of clinically relevant pathologies that should be considered ATRIAL FIBRILLATION 5 because they can contribute to the development of AF (Nattel, Shiroshita-Takeshita, Brundel, & Rivard, 2005). Treatment of AF has three main objectives: rate control, correction of the arrhythmia, and prevention of thromboembolism (Patterson et al, 2010). Control of the heart rate and rhythm is usually accomplished by using beta-blockers, calcium channel blockers, amiodarone, or digoxin (Patterson et al, 2010). If the heart does not respond to medications, electrical cardioversion or surgical ablation of accessory atrial pathways is considered. The CHADS2 (congestive heart failure, hypertension, age more than or equal to 75, diabetes mellitus, and stroke or transient ischemic attack history) scoring system helps identify the need for anticoagulation and direct its management based on the patient’s co-morbidities (Table 2). A score of 0-1 indicates that aspirin therapy is sufficient, while a score of 2-6 indicates the need for warfarin in the absence of other contraindications (Patterson et al, 2010). Table 2 CHADS2 Scoring System