Diseases of the Myocardium, Acquired Flashcards
What class of medication should you avoid in cocaine toxicity
Beta blockers
Cocaine intoxication clinically presents as a
Cocaine intoxication clinically presents as a sympathomimetic toxidrome that includes tachycardia, hypertension, diaphoresis, chest pain, and mydriasis. Patients may also have hyperthermia and cardiac dysrhythmias.
Cocaine works by
Cocaine exerts its affects by stimulating and blocking reuptake of multiple neurotransmitters (dopamine, epinephrine, norepinephrine, and serotonin). Although many receptors are activated, the most profound effect is the adrenergic stimulation caused by norepinephrine and epinephrine, resulting in vasoconstriction, increased myocardial contractility, increased myocardial oxygen demand, and increased heart rate.
Cocaine-related chest pain ensues as a result of
Cocaine-related chest pain ensues as a result of coronary vasospasm and ischemia due to increased myocardial oxygen demand.
Cocaine-related chest pain is most effectively managed through
benzodiazepines, which will decrease the oxygen demand and sympathetic effects
Should you give aspirin in cocaine induced chest pain
Aspirin should be administered as well since cocaine induces platelet aggregation
Beta-blockers are generally recommended to be avoided in cocaine-related chest pain due to
Beta-blockers are generally recommended to be avoided in cocaine-related chest pain due to the unopposed alpha stimulation that can lead to increased cardiac ischemia. Concern that it can lead to worsening vasoconstriction.
Cocaine effects
True or false: preexistent cardiovascular disease is a prerequisite for cocaine-related myocardial ischemia.
False
Rapid Review: Cocaine Intoxication
Myocarditis
Myocarditis occurs when there is inflammation and necrosis of the myocardium. This typically occurs after an infection and can present with fever, chills, and chest pain. The diagnosis is more likely in a young patient. ECG may demonstrate nonspecific ST segment changes, T wave inversions, and QT prolongation. Echocardiography can demonstrate global hypokinesis. Troponins will be elevated given the damage to the cardiac myocytes. Other tests can include an erythrocyte sedimentation rate or C-reactive protein, serum viral titers, and a cardiovascular MRI. An endomyocardial biopsy is the gold standard to confirm the diagnosis, although it is rarely done. The prognosis is variable in myocarditis, and sudden death is possible even in young and previously healthy patients. The treatment of myocarditis is supportive care, with heart failure medications and antidysrhythmics as needed.
Myocarditis Chart
What is the treatment of pericardial tamponade in a hemodynamically unstable patient?
Pericardiocentesis.
Rapid Review: Myocarditis
What is the biggest risk factor for the development of a left ventricular aneurysm?
Left anterior descending coronary artery infarction
Left ventricular aneurysm
Left ventricular aneurysm formation is a potential complication following a myocardial infarction. Occurring in up to 15% of patients after myocardial infarction, it is characterized by a thinned, focal area of the myocardium and is four times as likely to involve the anterior or apical walls than the inferior or posterior walls. On echocardiogram, the involved segment will appear to paradoxically balloon outward during systole. Electrocardiographic findings include persistent ST segment elevation in the distribution of the recent myocardial infarction. Those at greatest risk for the development of a left ventricular aneurysm include patients with complete occlusion of the left anterior descending artery, delayed or incomplete reperfusion, and absence of collateralization. Treatment of left ventricular aneurysm includes afterload reduction, usually with an angiotensin-converting enzyme inhibitor, and anticoagulation, if there is evidence of significant left ventricular dysfunction or thrombus formation.
Left ventricular aneurysm Chart
Rapid Review: Left ventricular aneurysm
What are the three main complications related to development of a left ventricular aneurysm?
Heart failure, dysrhythmias, and thromboembolic disease.
The use of nitrates is contraindicated in patients who also take
sildenafil
Sildenafil is an
inhibitor of cyclic guanosine monophosphate specific phosphodiesterase type 5. It leads to an increased release of nitric oxide, resulting in smooth muscle relaxation and vasodilation
Sildenafil is commonly used to treat
Erectile dysfunction
Which electrolyte is increased with hydrochlorothiazide use?
Calcium (causing hypercalcemia).
Erectile Dysfunction
Rapid Review: PDE-5 Inhibitors
Which medication is the first line treatment for patients with acute decompensate heart failure
This patient presents with symptoms of acute decompensated heart failure and should be started on nitroglycerin therapy immediately. Patients present with shortness of breath, increased work of breathing, tachycardia, hypoxia, crackles on lung examination, and jugular venous distension. These patients experience acute worsening of left ventricular function and output secondary to a number of mechanisms including increased systemic vascular resistance. Therapy focuses on the reduction of preload to decrease the flow of blood into the lungs and afterload reduction to increase the effectiveness of the left ventricle. Both of these goals can be accomplished through the administration of nitroglycerin. At lower doses, nitroglycerin acts as a peripheral vasodilator and increases venous capacitance leading to decreased preload. At higher doses, nitroglycerin causes arterial vasodilation leading to decreased afterload. Because of its rapid onset of action, nitroglycerin is the first-line medication in patients with acute decompensated heart failure.
Rapid Review: Acute Decompensated Heart Failure
Nitrates chart
What life-threatening toxicity is associated with nitroprusside administration?
Cyanide toxicity.
Which medication has the greatest impact on reducing mortality in patients presenting with acute coronary syndrome?
Aspirin
Aspirin in ACS
Aspirin has been shown to have the greatest effect on reducing mortality in patients with acute coronary syndrome (ACS). Aspirin is an irreversible antiplatelet agent. It inactivates platelets for the life span of the platelet (8–10 days). Studies have demonstrated a 23% reduction in mortality for patients with acute myocardial infarction (AMI) who received aspirin but not thrombolytic therapy. Aspirin also works synergistically with thrombolytics (42% reduction in mortality). Overall, aspirin has a number needed to treat (to prevent death) of 42. Administration of aspirin (chewed and swallowed) is recommended in any patient with suspected ACS.
Which cardiac biomarker has the highest sensitivity and specificity?
Cardiac troponin
Initial Medical Therapy for ACS
Rapid Review: Ischemic Heart Disease
Which medication is contraindicated n an inferior STEMI
Nitroglycerin
Why is nitroglycerin contraindicated in an inferior MI
Patients with an inferior STEMI may have right ventricular infarct and be preload dependent. In a patient with an inferior STEMI, right ventricular infarct is suggested by the presence of ST elevation in lead III larger than that in lead II. A right ventricular infarct can be discovered by performing a right-sided ECG and looking for ST elevation in lead V4R. In these patients, a preload-reducing medication like nitroglycerin can lead to a precipitous drop in blood pressure.
Please interpret this EKG
A right ventricular infarct is suggested by the presence of ST elevation in lead III larger than that in lead II.
Right Ventricular Infarction Chart
Which coronary artery most commonly supplies the inferior wall with blood?
The right coronary artery.
Rapid Review: Inferior ST Elevation Myocardial Infarction
The Sgarbossa ST elevation myocardial infarction (STEMI) criteria
ECG predictors of myocardial infarction are used in the presence of a conduction delay like a left bundle branch block (LBBB). ST segment elevation of at least 1 mm that is concordant with the QRS complex in any lead meets one of the criteria for STEMI. Concordant means that the ST segment and QRS complex have the same direction. The two other criteria for STEMI include concordant ST segment depression of at least 1 mm in lead V1, V2, or V3 and ST segment elevation of at least 5 mm that is discordant with the QRS complex. However, this latter criterion is based on the original Sgarbossa criteria and has been replaced in the modified Sgarbossa criteria with excessive discordance, defined by an ST/S ratio > 0.25. The original Sgarbossa criteria assigned weighted scores to determine the likelihood of STEMI. However, in the modified Sgarbossa criteria, meeting any single criterion yields increased sensitivity without significant loss of specificity in the diagnosis of STEMI in the setting of a conduction delay.
Sgarbossa Criteria