WBR0359

Author	PageAuthor::Neeraja Danda M.B.B.S
Exam Type	ExamType::USMLE Step 2 CK
Main Category	MainCategory::Internal medicine
Sub Category	SubCategory::Cardiovascular
Prompt	[[Prompt::A 48 year old male presented to the emergency room with chest pain and diaphoresis . Electrocardiogram showed ST segment elevation in leads II, III, aVF. Angiogram revealed 75% stenosis in the right coronary artery and angioplasty was performed. While in the Intensive care unit the patient suddenly complains of dizziness , and dyspnea . Electrocardiogram on the monitor displays uncoordinated P waves and QRS complexes with an atrial rate of 90 beats per minute and ventricular rate of 45 beats per minute. What is the most likely diagnosis?]]
Answer A	AnswerA::Reinfarction
Answer A Explanation	AnswerAExp::'''incorrect''' Reinfarction would show new ST elevations or depressions on electrocardiogram.
Answer B	AnswerB::Sinus bradycardia
Answer B Explanation	AnswerBExp::'''Incorrect''' Sinus bradycardia refers to a heart rate less than 60 per minute with regular rhythm on electrocardiogram.
Answer C	AnswerC::Third degree atrioventricular block
Answer C Explanation	AnswerCExp::Uncoordinated firing of the atria and ventricles accompanied by dizziness, and dyspnea strongly suggest third degree heart block
Answer D	AnswerD::Multifocal atrial tachycardia
Answer D Explanation	AnswerDExp::'''Incorrect''' Multifocal atrial tachycardia is characterized by polymorphic P waves on electrocardiogram.
Answer E	AnswerE::Ventricular Tachycardia
Answer E Explanation	AnswerEExp::'''Incorrect''' Ventricular tachycardia is characterized by a wide QRS complex tachycardia on electrocardiogram
Right Answer	RightAnswer::C
Explanation	[[Explanation::Complications of myocardial infarction is a high-yield topic for USMLE exams. Sinus bradycardia, heart block, ventricular tachycardia, ventricular fibrillation, valvular or septal rupture and pericarditis are complications of myocardial infarction.Dizziness,dyspnea and an electrocardiogram showing uncoordinated P and QRS suggest third degree heart block. Educational Objective: Uncoordinated firing of the atria and ventricles accompanied by dizziness, and dyspnea strongly suggest third degree heart block . References:Page 71, 551, 552, 553, 558 Master the boards Step 2 Ck second edition, Page 73 Master the boards Step 3 2009 edition. Educational Objective: References: ]]
Approved	Approved::Yes
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