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Q8.

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docnikki
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02/19/08 - 11:01 AM

A 72-year-old man with a history of multiple admissions to the hospital for acute cholecystitis undergoes elective cholecystectomy. His recovery period is unremarkable until the day before discharge, when he suddenly begins to experience palpitations. He denies chest pain. An EKG reveals his baseline right bundle branch block (RBBB) and a new atrial flutter at a rate of 120 to 140/min. The patient is started on anticoagulation with heparin. He remains in atrial fibrillation over the next two days. His chest x-ray is normal, and laboratory studies demonstrate normal potassium, magnesium, and thyroid-stimulating hormone. Transesophageal echocardiogram was negative for intracardiac thrombi. The decision was made to proceed with chemical cardioversion.

The patient has a history of allergy to cephalosporins and aspirin. He is given intravenous procainamide. During the infusion, the telemetry reveals a rate of 230/min with wide QRS complexes. He is found to be pulseless. CPR is started, and he is defibrillated with 100 J, which restores sinus rhythm that then degenerates into atrial fibrillation.

What could have prevented this reaction?

(A) If the infusion of procainamide had been administered slower
(B) If the patient's allergy to procainamide had been known
(C) If quinidine had been used instead of procainamide
([font size="2"]D) If pretreatment before procainamide had been undertaken with propranolol, digoxin, or verapamil[/font]

farnsworth
Forum Newbie

Topics: 0
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02/19/08 - 02:11 PM

Good question. I had to look it up, the solution is... (D), from a veterinary medicine article.
Procainamide is off the market in some countries due to the unfavorable side effect profile. I am not sure about the US.

dr.wad
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02/20/08 - 01:56 AM

yes D.......seems like another one u have posted...

Adam
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02/20/08 - 05:48 AM

parameter wrote:
Procainamide is off the market in some countries due to the unfavorable side effect profile

you are right.. i didn't know that b4,, thanks

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docnikki
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Topics: 93
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02/21/08 - 06:50 AM

yup ure right...but why will the complexes be wide complexed with procainamide...?

docnikki
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02/21/08 - 06:50 AM

This is the explaination though...

The most likely explanation for his rhythm was one-to-one conduction of atrial flutter through an AV node. This could have been prevented through an adequate AV nodal blockade before administration of procainamide. Quinidine, which could have resulted in the same response, also requires an adequate AV nodal blockade before its administration. Both procainamide and quinidine actually speed conduction through the AV node. Drug allergies generally do not result in a rhythm disturbance. When procainamide is administered too rapidly, the abnormal response is hypotension, not progression to a wide complex tachycardia

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