A 75-year-old diabetic woman with a history of previous MI and an LVEF of 35% has been on amiodarone for paroxysmal AF for several years. On examination she is breathless at rest and has signs of congestive cardiac failure. She has heard about dronedarone and is wondering whether she can have it instead of amiodarone.
What do you advise her about dronedarone?
This woman appears to be in NYHA class IV heart failure and thus dronedarone is contraindicated according to NICE guidelines. Dronedarone is a structural analogue of amiodarone, but does not contain iodine and thus has a lower risk of skin, lung, and eye side effects. The ATHENA study showed a 24% relative risk reduction of the combined endpoint of cardiovascular hospitalization and death compared with placebo (mainly driven by a reduction in cardiovascular hospitalizations, especially for AF). Dronedarone was also found to reduce the ventricular rate response during AF by 10–15 bpm. Dronedarone is contraindicated in NYHA class III–IV heart failure but is recommended by NICE as an option in patients whose AF is not controlled by first-line therapy and who have at least one of the following risk factors: hypertension (requiring at least two different drugs), diabetes, previous TIA/stroke, LA ≥ 50 mm, LVEF ≤ 40%, and ≥70 years old. There is no evidence that dronedarone is more effective than amiodarone at maintaining sinus rhythm.
A 66-year-old woman with a past medical history of hypertension undergoes DC cardioversion for atrial fibrillation. Immediately following the procedure, transient ST elevation is seen. The patient is asymptomatic post-procedure but cardiac enzymes are taken 12 hours later. These show a normal troponin I but a raised CK. The SHO calls you to advise him on the significance of the ECG and blood tests.
What do you advise?
Transient ST elevation can be a normal finding post DC cardioversion. A rise in CK is also usually normal but neither troponin T nor troponin I should rise following DC cardioversion of AF.
A 40-year-old man presents to A&E with a 12-hour history of sudden-onset palpitations. He has no previous medical history of note and the clinical examination is unremarkable. His troponin is negative. His ECG shows atrial fibrillation with a ventricular rate of 130 bpm, his BP is 110/70 mmHg, and his oxygen saturation is 98%. He has no symptoms associated with his palpitations.
What is the best management?
The option of anticoagulation, rate control, and DC cardioversion is reasonable if the onset of atrial fibrillation is >48 hours or if unsure of duration. DC cardioversion could be performed immediately as the onset of AF appears to be acute, but there are no signs of haemodynamic compromise and therefore it does not need to be performed as an emergency. Beta-blockers are good for rate control but are less likely to cardiovert a patient to sinus rhythm than other options. Amiodarone is probably the first-choice drug for chemical cardioversion of patients with structural heart disease or heart failure. Digoxin is unlikely to cardiovert a patient to sinus rhythm and may even be profibrillatory. Flecainide is likely to cardiovert this patient faster than any of the other options, and is likely to be safe in a young patient with no evidence of cardiac disease.
A 72 year old man with symptomatic persistent atrial fibrillation is admitted for pulmonary vein isolation.
Which one of the following statements is most likely to be true?
The risk of stroke is around 1%. The risk of pulmonary vein stenosis/occlusion is around 2%. The success rates reported in the literature for persistent AF ablation are 55–80% at 1 year (this includes some patients who have had more than one procedure). The success rate for PAF ablation is higher at 70–90% at 1 year. Cardiac tamponade usually occurs during or very soon after the procedure, and rates as high as 6% have been reported.
A patient is admitted for a DC cardioversion for their persistent atrial fibrillation.
Which one of the following statements is true?
Biphasic waveforms are more effective than monophasic ones, requiring less energy and fewer shocks to cardiovert patients. Pretreatment with IV ibutilide, flecainide, or sotalol has been shown to decrease the energy requirement for DC cardioversion and increase the success rate. The initial success rate for persistent AF cardioversion is around 80%. All patients should be anticoagulated prior to cardioversion for persistent AF regardless of CHADS2 score. Increased left atrial size, duration of AF prior to cardioversion, previous recurrences, reduced LA function, and underlying cardiac disease are all known to increase AF recurrence risk.
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