Atrial Fibrillation Through the Years

ForwardInformation about a real patient is presented in stages (boldface type) to an expert clinician (Dr Valentin Fuster), who responds to the information, sharing his reasoning with the reader (regular type).A discussion by the authors follows.A 61-year-old man presents with 2 weeks of exertional dyspnea.Pertinent medical history includes hypertension, nephrolithiasis, and internal hemorrhoids.He takes no medications and has no known drug allergies.His father died after a myocardial infarction at 57 years of age.He formerly smoked 1 pack of cigarettes daily for 15 years but ceased tobacco use 10 years before presentation.He ingests 2 glasses of alcohol weekly and denies illicit drug use.His caffeine intake is limited.He is an architect and is married, with healthy children.On physical examination, his temperature is 98.0°F, blood pressure is 130/85 mm Hg bilaterally, pulse is irregular at 130 beats per minute, and respiratory rate is 18 breaths per minute with an oxygen saturation of 97% while breathing room air.He is a slender white man in no distress.His jugular venous pressure is elevated at 14 cm H 2 O.There is no thyromegaly, and the carotid upstrokes are brisk, without bruits.Cardiovascular examination reveals a rapid and irregular heart rhythm with variation in the intensity of the first heart sound.The point of maximal impulse is not displaced.The remainder of the chest and abdominal examination is within normal limits.The extremities are warm and show mild pitting edema.Laboratory testing is significant for normal renal function and electrolytes, but a hemogram reveals a mild thrombocytopenia of 90 000 platelets/μL.ECG demonstrates atrial fibrillation (AF) with an average ventricular rate of 123 bpm (Figure 1).Dr Valentin Fuster: This is a patient with presumably nonvalvular AF presenting with a rapid ventricular rate.This is the patient's first detected episode of AF, and the duration of the arrhythmia, including previously undetected episodes, is unknown.The symptoms of AF may be subtle, and patients may become accustomed to limitations in exertional capacity.An attempt to elucidate common precipitants for AF, including alcohol consumption, emotional or physical stress, and sleep deprivation, is imperative.Physical examination in this patient suggests congestive heart failure with jugular venous distension and pitting edema.The ECG demonstrates the absence of organized atrial activity and corroborates the physical examination finding of an irregular ventricular rhythm.Initially, the priority is to address the presenting problem and control the patient's heart rate.This can be accomplished with β-blockade, which should be initiated in low doses and with careful monitoring given the risk of subsequent exacerbation of heart failure in patients with severe ventricular dysfunction.Although nondihydropyridine calcium channel antagonists could also be effective, they have negative inotropic effects and are better avoided in patients with heart failure.Digoxin, with its positive inotropic effects, is useful in controlling the resting heart rate during AF in the setting of heart failure or hypotension, particularly in combination with β-blockade.However, its relatively slow onset time makes digoxin less effective for acute heart rate control, and its proarrhythmic potential and ineffectiveness in the setting of high sympathetic tone render it less useful as monotherapy.Amiodarone can be used as an additional rate control agent, but given the chance of cardioversion, it should be preceded by at least 3 weeks of therapeutic anticoagulation or imaging to rule out intracardiac thrombus (Figure 2). 1,2Long-term, lenient control of the heart rate in AF is easy to achieve and may be sufficient in many patients, but few patients with heart failure have been studied with this strategy, and strict heart rate control is mandatory for patients with tachycardia-related ventricular dysfunction.After ventricular rate control has been achieved, electric cardioversion should be attempted.The merits of rhythm or rate control aside, when AF is first discovered, I usually recommend an attempt at restoration of sinus rhythm, which may avert the progressive electric and structural remodeling that will ultimately make long-term maintenance of sinus rhythm difficult.Importantly, cardioversion should be delayed until the patient's volume status is improved, or early AF recurrence will be likely.Because the patient's AF duration is uncertain, transesophageal echocardiography before cardioversion is