CARDIOLOGY 1

60-year-old white male presents to the ER with sudden onset of chest pain, nausea, vomiting, and diaphoresis. He describes this chest pain as a squeezing sensation, it started 2 hours ago at rest, radiates to jaw, and is partially relieved by sublingual nitroglycerin. He has a history of 30 pack/year of cigarette smoking. He is a known hypertensive for the past 10 years and suffered a hemorrhagic stroke 6 months ago. His medications include aspirin, atenolol, and hydrochlorothiazide. On examination, PR: 76/min; BP: 139/79 mmHg; RR: 13/min; Temperature: 37.3C(99F). On auscultation, lungs are clear and heart sounds are normal. Chest x-ray is normal. EKG shows ST segment elevation of 2mm in leads V3 to V6. These ST changes persist after sublingual nitroglycerin. Which of the following steps is the most appropriate regarding the management of this patient?

A. IV tissue plasminogen activator, IV heparin, and aspirin

B. IV tissue plasminogen activator and aspirin

C. IV heparin, IV nitroglycerin, and aspirin

D. IV amiodarone and IV magnesium

E. Immediate coronary angiography and PTCA


The answer is E.
Immediate coronary angiography and PTCA


Explanation:

The above patient is likely to benefit from thrombolytic therapy, but he has a history of a relatively recent hemorrhagic stroke (less than 1 year ago). Thrombolytic therapy would put him at a tremendous risk for intracranial bleeding and is therefore contraindicated. In such circumstances, immediate coronary angiography and PTCA or stent is the procedure of choice.

Thrombolytic therapy is indicated when the chest pain is suggestive of MI and there is ‘ST’ segment elevation greater than 1 mm in two contiguous leads after sublingual nitroglycerin administration to rule out coronary vasospasm. Another indication for thrombolytic therapy is a new or presumably new left bundle branch block. Thrombolytic therapy is not indicated for an MI with ‘ST’ segment depression and it is also not indicated for unstable angina. In these settings, no proven benefit has been shown for thrombolytic therapy. Thrombolytic therapy can be given when ‘ST’ depression shows a posterior MI, especially in the setting of an inferior wall MI.

Absolute contraindications to thrombolytic therapy include: active internal bleeding; history of hemorrhagic stroke anytime, or an ischemic stroke within past year; known intracranial neoplasm; current systolic BP greater than 180 or diastolic BP greater than 110; or suspected aortic dissection.

Thrombolytic therapy with tissue plasminogen activator requires co-administration of heparin and aspirin for greater benefit. Tissue plasminogen activator is slightly more effective than streptokinase but it has a slightly more risk of intracranial bleeding. For streptokinase, co-administration of heparin is not required.

Treatment with IV heparin, aspirin, and IV nitroglycerin is indicated in cases of unstable angina and non-Q wave infarcts. In those cases, thrombolytic therapy has not been shown to be associated with a proven benefit.

IV amiodarone and IV magnesium are not useful in the setting of MI unless arrhythmias or low serum magnesium levels complicate it.