Answer to A fib: “You can’t Handle the Truth”
Correct answer is B. This is a heart sectioned obliquely in order to demonstrate all four chambers of the heart. The symptoms described in the stem of the question are consistent with development of atrial fibrillation. There is also evidence that cold weather may lead to the onset of the atrial fibrillation. Combined with the dry air and elevation at Steamboat and the drinking, the fibrillation led to the severe light headedness and the sequela of the events.
The atrioventricular node is located in the interatrial septum, near the coronary sinus. Importantly, after an AV node ablation, a pacemaker is necessary for proper heart function. The device is generally placed several weeks before the ablation is performed to ensure it is working well.
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Answer to this question is based on material presented in lectures 12 of the Thorax Lecture Series.
= Approximate location of SA node
= Approximate location of AV node
= Anterior papillary muscle right ventricle
= Posterior papillary muscle, left ventricle
= Approximate location of mitral valve