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Office of Education
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Caroline Bell: DiscussionCaroline describes her palpitations (awareness of the beating of the heart) as intermittent for a year and constant for 2 days. A continuous sensation suggests a tachyarrhythmia such as paroxysmal supraventricular tachycardia, atrial flutter, or atrial fibrillation. A momentary sensation such as a “flip flop” is more indicative of a premature beat. The physical exmaination reveals elevated blood pressure and an irregularly irregular pulse that suggests either atrial fibrillation, atrial flutter with variable block, ventricular or atrial ectopy, or multifocal atrial tachycardia. An undiagnosed irregular pulse is an indication for an EKG. Caroline Bell's EKG shows atrial fibrillation with a ventricular rate of about 120 beats per minute, normal QRS complexes, and non-specific t-wave changes. The diagnosis therefore is atrial fibrillation (AF) and hypertension. The common causes of AF are hypertension, coronary artery disease, and aging. However AF can result from virtually any form of intrinsic heart disease including valvular disorders and cardiomyopathy. Non-cardiac causes of AF include hyperthyroidism, electrolye imbalance, and acute stresses such as surgery and infection. Patients whose AF may have been caused by a critical event such as myocardial infarction or pneumonia should be admitted to the hospital. Other indications for admission include advanced age, decompensated cardiac status (chest pain or CHF), and rapid ventricular rate. Others can be safely treated in the out-patient setting. Since Caroline's ventricular rate is rapid and she is 75 years old, she should be admitted to the hospital promptly for treatment and tests. The diagnostic evaluation should include a CBC, Chem 7 panel, cardiac enzymes, and thyroid function tests, a chest x-ray, and an echocardiogram to assess cardiac structure and function. The important treatment themes are rate control, anticoagulation, and return to sinus rhythm. A beta blocker or calcium channel blocker is appropriate to slow the ventricular rate. Examples include initial doses of atenolol 25 mg po qd or or diltiazem 120 mg po qd. In the hospital either drug can be given iv in low doses every 30 minutes until the ventricular rate is controlled. The major complication of atrial fibrillation is systemic embolization most often resulting in stroke. Aspirin therapy is indicated for prophylaxis for individuals under age 65 without structural heart disease, hypertension, diabetes or a history of cerebrovascular insufficiency. Individuals with atrial fibrillation over age 65, or any individual with ischemic or structural heart disease, diabetes, or a history of TIA or stroke benefit more from Warfarin than from aspirin. AF will sometimes resolve within hours or days with or without beta or calcium blockers. If it does not resolve, electrical or pharmacologic cardioversion, most often with sotalol, can be attempted after approximately one month of starting coumadin. An alternative to the above approach would be to admit Caroline to the Emergency Department, start heparin, and perform a transesophageal electrocardiogram. If there is no evidence of intracardiac clot, cardioversion can be performed safely, followed by short term coumadin. Caroline will benefit from referral to a cardiologist who can oversee evaluation and treatment in the acute phase of her illness, and for periodic follow-up visits since the odds are that AF will recur within 2 years and eventually persist. Next: References for this case  |
