docnikki
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A 45-year-old man presents with the sudden onset of nausea, vomiting, and chest discomfort, which started three hours ago. The patient took Maalox and Tums, but they didn't relieve his symptoms. His past medical history is significant for gastroesophageal reflux disease.
Vital signs: temperature 100.9 F (rectal), heart rate 40/min, blood pressure 86/52 mm Hg, and respiratory rate 26/min. Physical examination is significant for jugular venous distension with clear lungs. EKG shows ST elevation in II, III, and AVF, and the chest x-ray is normal. Oxygen saturation is 98% on room air. Which of the following would be the most appropriate initial therapy?
(A) Aspirin, nitroglycerin, morphine, ACE inhibitors
(B) Transcutaneous pacemaker
(C) Thrombolytics
(D) Atropine sulfate
(E) Metoprolol
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| simi
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A ------ Inferior myocardial infarction
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| sandra
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D atropine to correct bradycardia n hypotension?
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| dr.wad
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B
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| deja_vu
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why B before D ?
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| dr.wad
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deja_vu wrote:
why B before D ?
beacause the pt is distressed..low BP
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| farnsworth
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D - if atropine fails to correct the bradycardia, use a pacer
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| redddd
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A should be the answer, In bradycrdia, correction of underlying cause is important. Docnikki whats the answer???
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| farnsworth
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giving morphine/nitroglycerine/aspirin (and heparin) will improve symptoms and halt the progression of the myocardial infarction and relieve the symptoms. Since the systolic blood is already <100mmHg, nitroglycerin is not indicated here. Furthermore, correction of the underlying cause of the MI would be restoring the patency of the coronary vessels (PCI, CABG, lysis, or waiting for spontaneous recanalisation of the thrombus). Meanwhile, low output failure should be addressed by symptomatic therapy (treating bradycardia w/ atropin, or pacemaker). IV dobutamine also works (increases heart rate as well as contractility, at the expense of an increase myocardial oxygen consumption).
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| deja_vu
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dr.wad wrote:
beacause the pt is distressed..low BP
So when do we give atropine then? Smiling patient with BP of 120/80? (kiddin)
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| farnsworth
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a transcutaneous pacer wipes the smile off the patient's face (without adequate analgosedation) ;-)
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| mitthoo
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I will go for D
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| docnikki
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D is correct!!
The combination of low blood pressure and bradycardia suggests a vagal response, so an anticholinergic agent, such as atropine, is the correct answer. Volume replacement is required, especially if hypotension persists after correction of the bradyarrythmia. Nitroglycerin, ACE inhibitors, and beta-blockers are contraindicated in this setting because of low blood pressure. Although thrombolytics should be given as soon as possible, they are not as urgent as using atropine to correct the heart rate. Beta-blockers are absolutely contraindicated in the presence of bradycardia with hemodynamic instability. A transcutaneous pacemaker should definitely be applied, but this question is asking you to determine the appropriate order of therapy. Atropine can be given more rapidly and may correct the problem in the short term. Also, atropine is certainly more comfortable than using the transcutaneous pacemaker with the amperage turned up high enough to capture the heart. In this patient, the heart rate must be fixed (thus raising the blood pressure) while you are getting the pacemaker hooked up. As soon as the blood pressure is fixed, thrombolytics can be given or angioplasty can be performed.
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| guangyu
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i think it is C. you can not use nitroglycerin to hypotension patient.
only use pacer and atropine will increase HR, and make MI worse. so the only choice is C
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| farnsworth
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@guangyu: C is the a good therapeutic option (still inferior to PCI/PTCA), but the patient is severely hemodynamically compromised. Low blood pressure and bradycardia are hinting at a low cardiac output, an ominous sign in myocardial infarction. You have to act fast now, if you are not able to stabilize the patient (atropin, dobutamine, epinephrine, pacer), he won't live long enough to experience the benefits of thrombolytics.
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| docnikki
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guys! this patient is unstable...had he been stable with his hypotension and bradycardia the the DOC would have been Epinephrine...no? I knbow its not in choices..i just want to make sure that the funda is correct for a stable pt !
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| farnsworth
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I have some problem considering a patient w/ hypotension and bradycardia stable. Anyway, I would go for atropine first, then dobutamine or epinephrine, followed by pacemaker.
Dobutamine increases contractility and heart rate, thus increasing cardiac output. Systemic vascular resistance is affected in that way, that the beta1 receptors mediate relaxation of large arteries (afterload is decreased, comes in handy in myocardial infarction ;-). If the heart rate goes up to 90bpm and the blood pressure remains at 80/50, I would add norepinephrine (a1 agonist) to increase systemic vascular resistance. The problem is: you don't know myocardial contractility and if there are any valve defects. This is a good indication for a TTE/TEE to guide your therapy (fluid status? contractility?). You may also add phosphodiesterase inhibitors (milrinon, for increasing contractility, reducing pulmonary vascular resistance in severe heart failure), or vasopressin (increasing systemic vascular resistance via V1 receptor, e. g. in septic patients) guided by the TEE.
If the blood pressure was 60/35 and the heart rate 40bpm, I would directly proceed to epinephrine, and put in a transvenous pacer (if pt still bradycardic w/ epi), and do an TEE for therapy guidance (fluids, norephinephrine, milrinone, vasopressin).
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