A 22-year-old male is admitted to the intensive care unit (ICU) after sustaining a cardiac arrest while playing soccer in a rural area. Cardiopulmonary resuscitation was performed, but no automatic external defibrillator was available; he was intubated in the field because of poor mental status. He is transferred to your tertiary care ICU. Examination reveals an ejection systolic murmur, and he followed commands when sedation was lightened. Transthoracic echocardiography reveals discrete upper septal hypertrophy measuring 18 mm and an elevated left ventricular outflow velocity. He successfully passes a spontaneous awakening trial and spontaneous breathing trial. Unfortunately, at that time, he develops atrial fibrillation, became hypotensive to blood pressures of 94/52, and FiO2 was increased from 0.4 to 0.6 in response to desaturations to the low 80s.
The best treatment for this patient’s atrial fibrillation is:
Correct Answer: D
Hypertrophic cardiomyopathy (HCM) is defined as left ventricular wall thickness >15 mm not explained by loading conditions including hypertension or aortic valve stenosis. Patients with HCM are at risk for lethal ventricular arrhythmias, and cardiac arrest may be the initial presentation, whereas other patients may experience dyspnea, palpitations, chest pain, or syncope as presenting symptoms. However, the most common arrhythmia experienced by patients with HCM is atrial fibrillation that occurs in approximately 20% to 25%.
HCM may cause obstruction to left ventricular outflow, caused by systolic anterior motion of the anterior mitral valve leaflet. Conditions that worsen the obstruction include hypotension and tachycardia. Atrial fibrillation can cause both of these. Also, patients with HCM are markedly dependent on the “atrial kick” for adequate ventricular filling. These conditions can worsen left ventricular outflow tract obstruction resulting in flash pulmonary edema and hemodynamic collapse.
As such, any patient with hypertrophic obstructive cardiomyopathy experiencing hemodynamic stressors with acute changes to preload or afterload, such as intubation or extubation, should have close monitoring and titration of hemodynamics. Avoiding hypotension by maintaining preload and afterload, preventing a hyperdynamic state, and maintenance of sinus rhythm are essential to optimize hemodynamics.
Digoxin and norepinephrine should be avoided in this patient population as it can increase contractility and thereby worsen left ventricular outflow tract obstruction. In patients with HCM who develop atrial fibrillation, AHA/ACC guidelines recommend amiodarone or disopyramide combined with beta blocker or nondihydropyridine calcium channel blocker as first line medications. Although beta blocker can help reduce left ventricular outflow tract obstruction, these could possibly exacerbate hypotension and thus not the best initial choice. In the setting of moderate hypotension, amiodarone bolus and load is the best initial choice for medical management. Should the hypotension be profound, immediate cardioversion would be the best step in management.
A 75-year-old female with prior history of hypertension and hyperlipidemia presents with acute onset chest pain and dyspnea for last 4 hours ago. Physical examination revealed bilateral rales, cool extremities, and diaphoresis. She had no murmurs on auscultation. ECG revealed 1.5-mm ST segment elevations throughout the precordial leads. High-sensitivity troponin was elevated at 100 ng/L. Left coronary angiogram reveals nonobstructive coronary disease and ventriculography shows apical ballooning with sparing of base as well as globally reduced ejection fraction.
Left ventriculography on cardiac catheterization.
On arrival to the ICU she has bibasilar rales with oxygen requirement of 6 L/min via nasal cannula. Blood pressure is 95/48 mm Hg and HR is 122 beats per minute.
Which of the following medications should be avoided at this stage?
Correct Answer: B
Patients with Takotsubo cardiomyopathy often have a clinical presentation that is similar to those patients presenting with acute coronary syndrome. The wall motion abnormalities seen in Takotsubo cardiomyopathy extend beyond a single vascular territory, but multivessel coronary lesions must be excluded. Diagnostic modality of choice is coronary angiography. When obstructive coronary artery disease is seen in one vessel, but the wall motion abnormalities extend beyond one vascular territory, the diagnosis of Takotsubo cardiomyopathy may be suggested. The most classic phenotype of Takotsubo cardiomyopathy is the apical ballooning with basilar sparing, seen on left ventricular catheterization or on transthoracic echocardiography. Other morphologies include midventricular, biventricular, and an “inverted” form with basal hypokinesis. The underlying pathophysiology is thought to be related to catecholamine surge resulting in myocardial myocyte dysfunction. Takotsubo cardiomyopathy is more likely to affect women than men and often occurs in postmenopausal women who experienced a hemodynamic, physical, or emotional stressor. It can occur secondary to medical conditions including sepsis, subarachnoid hemorrhage, and pheochromocytoma. Mortality is similar to that of STEMI in the acute phase for hospitalized patients, 4% to 5%. Complications of Takotsubo cardiomyopathy include cardiogenic shock, severe mitral regurgitation, arrhythmias, pulmonary edema, and left ventricular outflow tract obstruction (particularly in patients with preexisting left ventricular upper septal hypertrophy).
Studies have reported increased mortality in Takotsubo cardiomyopathy with catecholamines. However, a calcium sensitizer called levosimendan may theoretically be used in place of inotropes and vasopressors, though this medication is not available in the United States. ACE inhibitors may help with recovery of cardiac function but should be avoided in the early phase of cardiogenic shock. Beta blockers have not shown benefit in Takotsubo cardiomyopathy and are contraindicated in cardiogenic shock or decompensated heart failure. Management is guided by standard heart failure measures, including afterload reduction and diuresis.
A 44-year-old female, G1P0, at 36 weeks gestation presents with worsening shortness of breath, lower extremity edema, and fatigue. Vital signs are notable for blood pressure of 84/58 mm Hg, heart rate of 144 beats per minute, respiratory rate 38 breaths per minute, and oxygen saturation of 92% while breathing room air. Examination is notable for 2+ bilateral lower-extremity pitting edema and bibasilar rales extending one-third of the way up bilateral lung fields. Urinalysis shows no protein and indices of renal and hepatic function are normal. Diuretics and afterload reduction with hydralazine and nitrates are started. Echocardiography shows left ventricular dilatation and severe left ventricular dysfunction with ejection fraction of 15%. Cesarean section delivery is performed, but her hemodynamics continue to worsen. Further diagnostic testing including coronary angiography at time of pulmonary artery catheter placement does not reveal alternate etiology, but she is noted to have a cardiac output of 2.1 L/min (cardiac index of 1.3 L/min/m2 ). Unfortunately, her clinical condition worsens and she develops progressive cardiogenic shock refractory to medical therapy including norepinephrine, milrinone, and epinephrine.
The most appropriate next step in management is:
Correct Answer: C
Peripartum cardiomyopathy is a condition that can occur from 1 month before delivery up to 5 months following delivery and is characterized by left ventricular ejection fraction <45%, and no prior history of cardiac disease. Peripartum cardiomyopathy is a diagnosis of exclusion and other causes of heart failure must be exonerated. Diagnostic testing should be driven by an interdisciplinary team and often includes transthoracic echocardiography, as well as cardiac MRI, endomyocardial biopsy, and coronary angiography. Cardiac workload increases during pregnancy as a result of increased circulating volume, heart rate, and stroke volume. This results in a net increase in cardiac output of approximately 20% to 50%. Vascular resistance decreases by about 20% but rises in the third trimester.
Management of peripartum cardiomyopathy is similar to management of other etiologies of heart failure, but with mindfulness regarding teratogenicity of medications. During the gravid period, beta blockers and hydralazine may be used for medical afterload reduction under close monitoring to avoid decreases in uretoplacental perfusion. The main stays in medical management following delivery are ACE inhibitors and beta blockers. Optimization of volume status and management of anemia are additional considerations in management. Peripartum cardiomyopathy is associated with atrial and ventricular arrhythmias, the most common of which is atrial fibrillation.
As with other cardiomyopathies, management of patients with shock and clinical instability should include vasopressors and inotropes. However, phenylephrine should be avoided as it primarily increases afterload without providing inotropy. Appropriate consideration of mechanical circulatory support includes ventricular assist devices and extracorporeal membrane oxygenation, whether as a bridge to recovery or transplantation. For patients with hemodynamic instability, cesarean delivery is preferred to minimize hemodynamic stressors of vaginal birth. Over 50% of women with peripartum cardiomyopathy eventually recover ejection fraction. However, some will require mechanical support as a bridge to transplant or recovery. Those requiring mechanical support have better survival than women with other nonischemic or ischemic cardiomyopathies.
A 22-year-old male with no known medical history presents with insidious fatigue, nonproductive cough, and shortness of breath with exertion over the prior 3 weeks. His laboratory test results are notable for an elevated high sensitivity troponin to 60 ng/L, and an NT-proBNP elevated to 2,400 pg/mL. Ejection fraction on transthoracic echocardiogram is noted to be 15% but a normal LV dimension and wall thickness, with no other structural abnormality. He is admitted to the Cardiac ICU for further monitoring and management. You are suspicious for myocarditis. He exhibits no dysrhythmia on telemetry. His symptoms improve with medical management.
The next best test to confirm a diagnosis is:
Viral myocarditis is one of the most common causes of myocarditis. It may be caused by a variety of viral infections including hepatitis C, HIV, and enteroviruses among others, as well as bacterial and parasitic infections. Viral myocarditis may be preceded by upper respiratory tract symptoms, gastroenteritis, fatigue, fevers, and myalgias, followed by the onset of heart failure symptoms. Presentation can vary from occult heart failure to cardiovascular collapse or complex ventricular arrhythmias. With advances in imaging, cardiac MRI has been particularly useful in diagnosis of myocarditis. In myocarditis, cardiac MRI may show late gadolinium enhancement and relative myocardial enhancement compared to skeletal muscle, indicating damage, scaring, edema, and increased capillary permeability.
Once MRI suggests myocarditis, endomyocardial biopsy is useful as it may exonerate other infiltrative etiologies including sarcoidosis, amyloidosis, and hemochromatosis. Biopsy is still considered the gold standard for diagnosis. However, the biopsy of the native heart is not without risks, such as ventricular perforation, valvular damage, and vascular injury. Thus, endomyocardial biopsy may be useful in select patients after cardiac MRI or when hemodynamic instability or need for rapid tissue diagnosis requires expeditious biopsy. Although cardiac PET scans can also assist in confirming the diagnosis of myocarditis, they are not easily available and needs preparation before testing and thus not the diagnostic modality of choice. Although viral serologies may be positive in a select number of patients, the overall sensitivity is poor, and thus these results are unlikely to change management. In this patient, with clinical improvement on medical management, cardiac MRI may be the next best test, to avoid risks of endomyocardial biopsy while assisting in assessment of a diagnosis, with biopsy considered only if there is no definitive diagnosis made by cardiac MRI and or concerning clinical trajectory.
A 48-year-old male with no known medical history came to the emergency room reporting worsening dyspnea on exertion. ECG is without ischemic changes and high-sensitivity troponin is modestly elevated at 68 ng/L. He is quickly admitted to the cardiac intensive care unit in advanced cardiogenic shock and with recurrent ventricular tachycardia despite diuretics, inodilators, lidocaine, and amiodarone. Emergent myocardial biopsy at time of initiation of mechanical support reveals lymphocytes and multinucleated giant cells.
Which of the following agents is an appropriate treatment?
Correct Answer: A
Giant cell myocarditis is a type of myocarditis characterized by cardiovascular collapse, with frequent ventricular arrhythmias and/or advanced atrioventricular heart block. The gold standard for diagnosis is endomyocardial biopsy. Although given the potential for sampling bias, a negative first biopsy with a high clinical suspicion should warrant consideration for repeat biopsy. Cardiac MRI and cardiac PET scan can help identify affected areas and can assist with biopsy planning, increasing the yield. In giant cell myocarditis, pathology reveals lymphocytic infiltrate with multinucleated giant cells. Beyond the initial presentation, patients with giant cell myocarditis are at high risk for malignant ventricular arrhythmias.
Therapeutically, there is no clear mortality benefit for the use of IVIG in patients with giant cell myocarditis. Literature suggests improved survival in patients receiving immunosuppresive therapy with multiple agents: azathioprine, cyclosporine, antithymocyte globulin, methotrexate, mycophenolate mofetil, and glucocorticoids. IVIG or glucocorticoids alone is less effective. NSAIDs are not helpful in myocarditis and may worsen heart failure. The patient with giant cell myocarditis should also be evaluated for mechanical circulatory support.
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