inappropriate shock in the setting of a stable rhythm (such as seen with the
patient in question). The patient in this scenario is receiving a shock while he
is in sinus rhythm. Some potential causes of inappropriate shock delivery
include false sensing of supraventricular tachycardias, muscular activity (eg,
shivering), sensing T waves as QRS complexes, unsustained tachydysrhyth-
mias, and component failure. AICDs are generally inactivated by placing a
magnet over the AICD generator.Although, there is some variability
depending on the generation of the AICD, most EDs have a special donut
magnet that is reserved for this function. If the patient subsequently experi-
ences a dysrhythmia in the setting of having his or her defibrillator tuned off,
the physician should use the bedside defibrillator to treat the patient.
Sending the patient back to the radiology suite (a)will not temporarily
turn off the AICD. However, radiographs are important in detecting AICD
lead fractures. Most patients carry a manufacturer card and it is often pos-
sible to contact the AICD company. However, it is not appropriate to wait
for a representative (b)to arrive at the hospital to deactivate the AICD. (c)
The patient will require that his AICD be interrogated to confirm that he
was not having runs of a shockable rhythm. Either a cardiologist or com-
pany representative has the ability to do this. However, it is ill advised to let
the AICD inappropriately deliver shocks to the patient while you adminis-
ter pain medication. The AICD should not be removed (e)from the chest
wall in the ED. If this procedure is required (if the device was a source of
infection), it should be performed by a cardiothoracic surgeon in the oper-
ating room.
36.The answer is b.(Rosen, pp 1154-1155.)The patient’s presentation is
consistent with acute mitral valve regurgitationbecause of a ruptured
papillary musclein the setting of an AMI. Patients usually present with
pulmonary edema in the setting of an AMI.Chest x-ray characteristically
reveals pulmonary edema with a normal heart size. The characteristic mur-
mur of mitral regurgitation is a holosystolic murmur that is loudest at
the apex.
(a)Critical aortic stenosis produces a loud systolic murmur that is best
heard at the second right intercostal space and radiates to the carotids.
(c)The classic finding of a pericardial effusion is a pericardial friction rub.
(d)CHF does not cause a murmur but rather an extra heart sound (S 3 ) from
fluid overload. (e)Aortic dissection is associated with a murmur of aortic
insufficiency.
Chest Pain and Cardiac Dysrhythmias Answers 43