A 64-year-old man with a history of hypertension and diet-controlled type 2 diabetes mellitus comes to the office due to generalized malaise and palpitations for the past 2 weeks. An echocardiogram last year showed mild left atrial dilation and left ventricular hypertrophy. The patient's medications include lisinopril and hydrochlorothiazide. Blood pressure is 170/90 mm Hg. ECG rhythm strip is shown in the exhibit. Which of the following is the most appropriate next step in management of this patient?

Question

A 64-year-old man with a history of hypertension and diet-controlled type 2 diabetes mellitus comes to the office due to generalized malaise and palpitations for the past 2 weeks.  An echocardiogram last year showed mild left atrial dilation and left ventricular hypertrophy.  The patient's medications include lisinopril and hydrochlorothiazide.  Blood pressure is 170/90 mm Hg.  ECG rhythm strip is shown in the exhibit.  Which of the following is the most appropriate next step in management of this patient?

Quizplus · Accepted Answer

11ec25c8_d336_4a3a_bc81_1d4fbb43466e_MD0003_00 This patient with 2 weeks of malaise and palpitations has an ECG showing an irregularly irregular rhythm with an absence of organized P waves, consistent with atrial fibrillation. The ventricular rate is elevated at approximately 100/min. Patients with evidence of hemodynamic instability (eg, severe hypotension, confusion, ischemic chest pain) usually have a ventricular rate >150/min and should undergo emergency electrical cardioversion (Choice B). In contrast, the initial management of those who are hemodynamically stable typically focuses on rate control with atrioventricular (AV) node blocking agents to reduce symptoms and help prevent tachycardia-induced cardiomyopathy. ECG 100/min For long-term rate control (eg, typical goal rate of <80/min at rest, or lower if coronary artery disease is present), a beta blocker (eg, metoprolol) or nonhydropyridine calcium channel blocker (eg, verapamil, diltiazem) is given initially. A second agent can then be added if additional rate control is needed (eg, metoprolol added to diltiazem). Digoxin is not used in the acute setting or as monotherapy, but it is particularly useful as a second agent in patients with left ventricular systolic dysfunction (due to a positive inotropic effect). Amiodarone has rate-control properties (due to inhibition of calcium channels in the AV node) and is sometimes used as a third-line agent for rate control. A rhythm-control strategy is pursued in some patients using nonemergency electrical cardioversion and/or pharmacologic rhythm-control agents (eg, amiodarone, dofetilide, flecainide). Regardless of whether rate or rhythm control is used, all patients should undergo an assessment of thromboembolic risk (eg, CHA₂DS₂-VASc score) and should be initiated on chronic anticoagulation when appropriate. CHA₂DS₂-VASc score (Choice A) Adenosine blocks conduction through the AV node, but its effects are short-lived. The drug is most useful in helping to determine the specific rhythm present in rapid supraventricular tachycardia or to help terminate atrioventricular nodal reentrant tachycardia (AVNRT), but it is not useful for rate control of atrial fibrillation. atrioventricular nodal reentrant tachycardia (AVNRT) (Choice C) Carotid sinus massage increases vagal stimulus to the AV node and may be helpful in terminating AVNRT; however, as with adenosine, the blocking effects on the AV node are short-lived and the utility for atrial fibrillation is minimal. (Choice E) Lidocaine is sometimes used for rhythm control of ventricular tachycardia, but it is not useful for atrial arrhythmias. Educational objective: The initial management of atrial fibrillation usually focuses on rate control; a beta blocker (eg, metoprolol) or nondihydropyridine calcium channel blocker (eg, verapamil, diltiazem) is given initially. Emergency electrical cardioversion is indicated only in patients who are hemodynamically unstable (eg, severe hypotension). References: Low-dose diltiazem in atrial fibrillation with rapid ventricular response. (http://www.ncbi.nlm.nih.gov/pubmed/20825912) Rate control in atrial fibrillation. (http://www.ncbi.nlm.nih.gov/pubmed/27560277) Who, when, and how to rate control for atrial fibrillation. (http://www.ncbi.nlm.nih.gov/pubmed/18281823)

A 64-Year-Old Man with a History of Hypertension and Diet-Controlled