(a)Digoxin is vagotonic. It has a slow onset that may take several
hours or more to work. It should be avoided if cardioversion is being con-
sidered because it can lead to a fatal dysrhythmia. (b and c)Lidocaine and
amiodarone, although may be effective in treating narrow-complex tachy-
cardias, are agents generally used to treat wide-complex or ventricular
tachycardias. (e)Bretylium is no longer available in the United States as it
has a poor safety profile.
22.The answer is e.(Rosen, pp 1011-1049.)This ECG depicts an acute
anterior wall myocardial infarction with ST elevations in leads V1 to V4.
The patient is also hypotensive secondary to cardiogenic shock.The
preferred treatment for an ST-elevation MI is primary percutaneous inter-
vention (eg, angioplasty, coronary stent). It has shown to improve long-
term mortality over (d)thrombolytic therapy. As a stabilizing measure, the
patient may require an intra-aortic balloon pump. This is a mechanical
device that is used to decrease myocardial oxygen demand while at the
same time increasing cardiac output. By increasing cardiac output it also
increases coronary blood flow and therefore myocardial oxygen delivery. It
is inserted through the femoral artery.
(a)β-Blockers and CCBs are contraindicated in patients who are
hypotensive.(b)The patient does not have a dysrhythmia and therefore
should not be cardioverted. (c)Calcium gluconate is the agent of choice for
individuals with ECG signs of potassium toxicity. It does not have a role in
the management of acute MI.
23.The answer is c.(Tintinalli, p 356.)Sildenafil (Viagra)is a selective
cyclic guanosine monophosphate (GMP) inhibitor that results in smooth-
muscle relaxation and vasodilation by the release of nitric oxide. It is used
in men for erectile dysfunction. It is contraindicated to administer nitro-
glycerinto individuals who have taken sildenafil in the previous 24 hours.
The combination of nitroglycerin and sildenafil can lead to hypotension and
death. If nitrates are coadministered with sildenafil, the patient should be
closely monitored for hypotension. Fluid resuscitation and pressor agents
may be needed to restore BP.
(a)Aspirin is contraindicated in individuals with an anaphylactic
allergy or active bleed. (b)Heparin is contraindicated in individuals with
heparin-induced thrombocytopenia, and those who are actively bleeding.
(d)Metoprolol is contraindicated in hypotensive individuals. (e)Morphine
sulfate is contraindicated in patients with respiratory depression.
36 Emergency Medicine