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Average 4.6 of 7 Ratings
A 78-year-old man presents to the emergency room with a three day history of palpitations. He denies dizziness, dyspnea, and chest pain, and says he sleeps comfortably on one pillow each night. His history is significant for diabetes mellitus type 2, hyperlipidemia, and hypertension. Medications include glyburide, lisinopril, and hydrochlorothiazide. The patient has a ten pack-year history of smoking but quit 15 years ago. He does not drink alcohol or use drugs. His heart rate is 115/min and his blood pressure is 145/95 mmHg. Physical examination demonstrates no evidence of heart failure. Electrocardiogram shows atrial fibrillation with rapid ventricular response. Which of the following is an appropriate therapy for this patient:
Metoprolol and aspirin
Metoprolol and warfarin
Digoxin and aspirin
Digoxin and warfarin
Diltiazem and aspirin
Select Answer to see Preferred Response
Medical treatment for atrial fibrillation in stable patients centers around rate control and anticoagulation. This patient's CHADS2 score is 3 (age, hypertension, and diabetes), so in addition to rate control with a non-dihydropyridine calcium channel blocker or beta-blocker, warfarin is indicated for anticoagulation.
The CHADS2 score is a clinical prediction rule for estimating the risk of stroke in patients with atrial fibrillation. The score dictates whether a patient should be treated with aspirin or warfarin anticoagulation therapy. One point is assigned for each of the following: congestive heart failure, blood pressure consistently above 140/90 mmHg, age greater than or equal to 75 years, and diabetes mellitus. Two points are added for prior stroke or TIA or thromboembolism. Patients with a score of zero can safely be treated with aspirin. A score of one indicates moderate risk and either aspirin or warfarin is acceptable. If CHADS2 is two or greater, the patient is high risk for embolic complications and warfarin is indicated.
Guierrez and Blanchard review the diagnosis and treatment of atrial fibrillation and highlight the preference of rate control over rhythm control. The latter is considered if rate control cannot be obtained or if there are persistent symptoms despite adequate rate control. Anticoagulation therapy is needed as an additional measure to lower stroke risk. Warfarin is superior to aspirin or clopidogrel in preventing stroke, despite its narrow therapeutic range and increased risk of bleeding.
Deedwania and Huang explain how dabigatran, a direct thrombin inhibitor, is now approved by the USFDA for stroke prophylaxis in nonvalvular atrial fibrillation. Recent studies have found it to be superior in preventing stroke and systemic embolism and to have a similar bleeding risk when compared with warfarin.
Illustration A is a table of the CHADS2 scoring and the appropriate treatments for each risk category.
Illustration B elucidates the mechanisms of action of some of the anticoagulants.
Answer 1 and 5: This patient’s CHADS2 score is 3, indicating that warfarin is preferred over aspirin as anticoagulation therapy.
Answer 3 and 4: Digoxin can be used for rate control in atrial fibrillation patients with congestive heart failure, who are intolerant of beta blockers or non-dihydropyrididine calcium channel blockers, though one of the latter two would be the preferred.
Gutierrez C, Blanchard DG.
Am Fam Physician. 2011 Jan 01;83(1):61-8. PMID: 21888129 (Link to Abstract)
Deedwania P, Huang GW.
Rev Cardiovasc Med. 2012;13(2-3):e89-104. PMID: 23160166 (Link to Abstract)
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Average 5.0 of 2 Ratings
A 76-year-old male with a 5 year history of atrial fibrillation presents to the Emergency Department with an inability to move his left leg. The patient notes that he first noted that his leg "felt funny" about two hours ago, and that it appeared to be more pale than normal. Since the leg started feeling funny, his ability to move it has decreased, to the point where he can no longer move it. He recently ran out of his warfarin, and hasn't taken any in two weeks. On physical exam his vital signs are within normal limits. His neurological exam reveals a pale, painful left leg with absent femoral and dorsalis pedis pulses. He has no other strength deficits and pulses in his right leg and right arm are intact. Which of the following would be the appropriate first action for this patient's condition?
No intervention necessary
This patient has an embolic occlusion of his left common iliac artery resulting in the pale, painful leg. The appropriate intervention would be an embolectomy to try and remove the occlusion.
Patients with atrial fibrillation are at risk for embolic complications, especially patients who abruptly discontinue their anticoagulation. Embolic complications can include stroke or other systemic embolizations. An embolism to the common iliac artery results in a pale, pulseless, painful leg, and requires immediate embolectomy to preserve the limb. Post-embolectomy complications include compartment syndrome which may require further surgical intervention (e.g., fasciotomy).
Answer 1: Thrombolysis would be appropriate for a patient with an ischemic stroke.
Answer 3. A fasciotomy might be indicated after this patient's embolectomy, but would not be the initial management for this patient.
Answer 4: An amputation would be premature but may be indicated if the patient developed an infected limb.
Answer 5: This patient has an intervenable condition; thus, an embolectomy would be indicated.
Average 3.0 of 6 Ratings
A 59-year-old woman presents to the ED with palpitations, which she has never experienced before now. Her past medical history is notable for chronic obstructive pulmonary disease (COPD) for which she has been hospitalized once in the last year. On exam her T 98.4F, HR 86, BP 105/70, RR 18, SpO2 94% on room air consistent with her baseline. Her EKG is shown in Figure A. What is the most common site of origin for ectopic foci causing the arrhythmia in this patient?
This patient has new onset atrial fibrillation; in atrial fibrillation the most likely site of origin for ectopic foci is the pulmonary veins.
Atrial fibrillation, the most common chronic arrhythmia, is a supraventicular arrhythmia that causes an irregularly irregular rhythm. Some risk factors include COPD, pulmonary embolism, chest surgery, myocardial ischemia, cardiomyopathy, pericarditis, hypertension, atrial septal defects, mitral or aortic valve abnormalities, atrial myxoma, hyperthyroidism, alcohol, and sepsis. Presentation can be asymptomatic, but common symptoms include dyspnea, palpitations, chest pain, or syncope. Hemodynamically stable patients should be rate-controlled with beta-blockers, diltiazem, or digoxin (in order of preference). If the patient has been in atrial fibrillation for less that 48 hours, cardioversion can be attempted without anticoagulation. If the arrhythmia had occurred for more than 48 hours or the duration is not known, anticoagulation should be achieved before cardioversion, unless left atrial thrombus has been ruled out by transeosophageal echocardiogram (TEE).
In a review of the diagnosis and management of atrial fibrillation, Gutierrez and Blanchard remind physicians that rate control is preferable to rhythm control, and rhythm control should only be used when rate control has failed. Although guidelines state a goal rate of 80bpm, recent data has shown that goal heart rates of less than 110 are non-inferior.
In chronic, uncontrolled atrial fibrillation, a single inciting ectopic focus can be the source. In a descriptive study of discrete radio-frequency ablation for the treatment of atrial fibrillation, Jai et al. found that this approach was curative in 9 out of 9 patients with a single inciting focus after 4±4 radiofrequency pulses.
Figure A shows an EKG of a patient in atrial fibrillation.
Answers 1 and 2: Although left and right atrium ectopic foci can cause atrial fibrillation, ectopic foci in the pulmonary veins are the most common. Of note, the tricuspid annulus is the most common site for atrial flutter.
Answers 4 and 5: Atrial fibrillation is a supraventricular tachycardia and by definition cannot originate in the ventricle.
Jaïs P, Haïssaguerre M, Shah DC, Chouairi S, Gencel L, Hocini M, Clémenty J.
Circulation. 1997 Feb 04;95(3):572-6. PMID: 9024141 (Link to Abstract)
Jaïs, CIRC 1997
Average 5.0 of 6 Ratings