Tag Archives: atrial fibrillation

Cardiology MCQ 22.4.15

 CARDIOLOGY MCQ & REVIEW

Q. All of the following statements about accessory pathways (AP) are correct except

A. Majority of APs conduct both antegradely and retrogradely

B. Around 50% of patients with preexcitation have bypass tracts that conduct only antegradely.

C. Retrograde only conduction is more common than antegrade only conduction via APs

D. In around 10% of patients spontaneous disappearance of preexcitation may be seen

Explanation:

 -The vast majority of A-V bypass tracts conduct both antegradely and retrogradely.

-Less than 5% of patients with preexcitation have bypass tracts that conduct only antegradely (1). This is much less common than the converse situation of retrogradely conducting bypass tracts in the absence of antegrade preexcitation (i.e., so-called concealed bypass tracts).
-In patients who manifest only antegrade conduction over their bypass tract, spontaneous circus movement tachycardia, either antidromic or orthodromic, is not usually observed, but when it is, it is antidromic. The primary rhythm disturbance they manifest is atrial fibrillation 

-Over time antegrade conduction over an A-V bypass tract may disappear. Chen et al. (2) noted a loss of preexcitation in one fifth of symptomatic patients with WPW. Only 7.8% lost retrograde conduction. Spontaneous loss of preexcitation has been observed in one fifth to one half of children with WPW.
References:
1. Hammill SC, Pritchett EL, Klein GJ, et al. Accessory atrioventricular pathways that conduct only in the antegrade direction. Circulation 1980;62:1335–1340.
2. Chen SA, Chiang CE, Tai CT, et al. Longitudinal clinical and electrophysiological assessment of patients with symptomatic Wolff-Parkinson-White syndrome and atrioventricular node reentrant tachycardia. Circulation 1996;93:2023–2032.
Answer: B
Keywords: Cardiology review, Cardiology, Multiple choice questions, medical students, Electrophysiology, Atrial fibrillation, WPW syndrome

Cardiology MCQ 21.4.15

CARDIOLOGY MCQ & REVIEW

Q. All of the following statements about atrial flutter – fibrillation in WPW syndrome are correct except

A. Atrial fibrillation can precipitate ventricular fibrillation in patients with accessory pathways

B. The incidence of atrial flutter and/or fibrillation appears to be higher in patients with A-V bypass tracts than in the normal population

C. Prevalence of atrial fibrillation is same in patients with manifest preexcitation and those with concealed preexcitation

D. Atrial flutter-fibrillation may be the presenting arrhythmia in 5% to 10% of patients with A-V bypass tracts

Explanation:

-In patients with WPW syndrome atrial flutter and fibrillation are less common presenting arrhythmias, but they are potentially more life threatening, because they can result in extremely rapid ventricular rates that precipitate ventricular tachycardia and/or fibrillation

-Atrial flutter-fibrillation may be the presenting arrhythmia in 5% to 10% of patients with A-V bypass tracts and occurs even more commonly when orthodromic or antidromic tachycardia also is present

-As many as 50% of patients with symptomatic arrhythmias will have atrial fibrillation of variable duration at some time.

-The incidence of atrial flutter and/or fibrillation appears to be higher in patients with A-V bypass tracts than in the normal population

-Atrial fibrillation appears to be five times more common when overt preexcitation (i.e., WPW) is present than in patients with concealed bypass tracts at similar locations and similar rates of tachycardias

-Patients with atrial fibrillation have a higher incidence of inducible atrial fibrillation than those without the arrhythmia

1. Klein GJ, Bashore TM, Sellers TD, et al. Ventricular fibrillation in the Wolff-Parkinson-White syndrome. N Engl J Med 1979;301:1080–1085.
2. Cosio FG, Benson DW Jr, Anderson RW, et al. Onset of atrial fibrillation during antidromic tachycardia: association with sudden cardiac arrest and ventricular fibrillation in a patient with Wolff-Parkinson-White syndrome. Am J Cardiol 1982;50:353–359.
Answer: C
Keywords: Cardiology review, Cardiology, Multiple choice questions, medical students, Electrophysiology, Atrial fibrillation, WPW syndrome

 

Antiplatelet Therapy for Stable CAD in AF Patients Taking an Oral Anticoagulant

Background—The optimal long-term antithrombotic treatment of patients with coexisting atrial fibrillation and stable coronary artery disease is unresolved, and commonly, a single antiplatelet agent is added to oral anticoagulation. The study investigated the effectiveness and safety of adding antiplatelet therapy to vitamin K antagonist (VKA) in atrial fibrillation patients with stable coronary artery disease.

Methods and Results—Atrial fibrillation patients with stable coronary artery disease (defined as 12 months from an acute coronary event) between 2002 and 2011 were identified. The subsequent risk of cardiovascular events and serious bleeding events (those that required hospitalization) was examined with adjusted Cox regression models according to ongoing antithrombotic therapy. A total of 8700 patients were included (mean age, 74.2 years; 38% women). During a mean follow-up of 3.3 years, crude incidence rates were 7.2, 3.8, and 4.0 events per 100 person-years for myocardial infarction/coronary death, thromboembolism, and serious bleeding, respectively. Relative to VKA monotherapy, the risk of myocardial infarction/coronary death was similar for VKA plus aspirin (hazard ratio, 1.12 [95% confidence interval, 0.94–1.34]) and VKA plus clopidogrel (hazard ratio, 1.53 [95% confidence interval, 0.93–2.52]). The risk of thromboembolism was comparable in all regimens that included VKA, whereas the risk of bleeding increased when aspirin (hazard ratio, 1.50 [95% confidence interval, 1.23–1.82]) or clopidogrel (hazard ratio, 1.84 [95% confidence interval, 1.11–3.06]) was added to VKA.

Conclusions—In atrial fibrillation patients with stable coronary artery disease, the addition of antiplatelet therapy to VKA therapy is not associated with a reduction in risk of recurrent coronary events or thromboembolism, whereas risk of bleeding is increased significantly. The common practice of adding antiplatelet therapy to oral VKA anticoagulation in patients with atrial fibrillation and stable coronary artery disease warrants reassessment.

Circulation.2014; 129: 1577-1585