Internal-Medicine

28 1: Cardiology
most useful initial investigation since it identifies
individuals with ST-segment elevation who may
be candidates for either thrombolysis or primary
angioplasty (PCI). The troponins are important
in diagnosing myocardial necrosis. The other
investigations may be important in looking for
alternate causes of chest pain once ST-elevation
MI has been ruled out. (Fuster, pp. 1252, 1256)
52. (C) Essential hypertension is the most likely
diagnosis. A secondary cause for hypertension
is found in only 10% of patients, with 90%
labeled as essential. Current recommendations
for initial workup of a hypertensive patient
include serum chemistry (glucose, potassium,
creatinine), urinalysis, and ECG. (Fuster, p. 1545)
53. (C) Coarctation of the aorta is the diagnosis.
There is a reverse 3 deformity of the
esophagus, the belly of which represents the
dilated aorta after the coarctation. The border
of the descending aorta shows a medial indentation
called the 3 or tuck sign, the belly of the
3 representing the poststenotic dilation and
the upper portion by the dilated subclavian
artery and small transverse aortic arch. (Fuster,
p. 1809)
54. (B) Note the abnormal humped contour of the
left ventricular border, with a curvilinear calcification
following the abnormal cardiac contour.
The presence of calcification in the
ventricular wall and the abnormal left ventricular
contour alerts one to the consideration of
a ventricular aneurysm. (Fuster, pp. 1321–1322)
55. (B) The cardiac rhythm is atrial flutter with 2:1
AV conduction. QRS complexes occur with
perfect regularity at a rate of about 150/min.
Their normal contour and duration indicate
that ventricular activation occurs normally via
the AV junction-His-Purkinje system. (Fuster,
pp. 841–842)
56. (B) The PR interval of the first two complexes
is normal at 0.20 seconds. The QRS duration is
0.16 seconds. The third P wave is nonconducted.
This cycle recurs in the remainder of
the strip. This is second-degree heart block of
the Mobitz type II variety. Note the wide QRS.
When this type of heart block develops, either
de novo or in the course of an AMI, a cardiac
pacemaker is usually recommended, as the
incidence of complete heart block is high in
this situation. (Fuster, pp. 901–903)
57. (D) The ST is depressed in leads II, III, aVF, and
V4–V6. These nonspecific abnormalities do not
indicate significant coronary heart disease,
especially in an apprehensive young patient.
Further evaluations should be guided by clinical
circumstances. (Fuster, pp. 304–305)
58. (E) The underlying rhythm is a regular sinus
rhythm with a rate of 85 beats/min. The sinus
rhythm is interrupted frequently by bursts of
irregular ventricular, premature beats. The sinus
rhythm is uninterrupted as can be determined
by plotting the PP intervals, which are regular.
The rhythm may be termed a chaotic ventricular
arrhythmia or ventricular tachycardia. Its
gross irregularity is unusual. Antiarrhythmic
therapy is usually not indicated for nonsustained
VT in the setting of thrombolytic treatment.
(Fuster, pp. 876–877)
59. (A) No atrial activity is detected. The ventricular
rate is slightly irregular. Beat number 4 is
a ventricular premature contraction. The T
waves are tall and markedly peaked. This type
of T wave is characteristic of hyperkalemia, as
is absence of visible atrial activity.
The potassium level was 8.2 mmol/L.
(Fuster, p. 313)
60. (A) Sudden death, defined as death within 1 hour
of onset of symptoms, is usually caused by cardiac
disease in middle-aged and elderly
patients, but in younger age groups noncardiac
causes predominate. There is a bimodal
distribution in the population, with the first
peak before 6 months of age (sudden infant
death syndrome). The most common coronary
artery finding is extensive chronic coronary
atherosclerosis, although acute syndromes do
occur. (Fuster, p. 1057)
61. (B) Over 90% of hypertensives in the general
population have essential hypertension. Only