QUICK RECERTIFICATION SERIES
Cardiac tamponade Lendell Richardson, MD
GENERAL FEATURES • Cardiac tamponade is a compressive syndrome that affects the heart. Significant fluid accumulation in the pericardial space can cause serious obstruction of blood flow into the ventricles. • The normal pericardial sac contains only a thin layer of pericardial fluid. Under usual circumstances, this sac can stretch to accommodate physiologic changes in cardiac volume. ¡ Once the pericardium’s reserve (or potential) volume is exceeded, the sac stiffens and becomes much less compliant. ¡ When the pericardium markedly stiffens, even small amounts of fluid accumulation can result in cardiac tamponade. ¡ This causes intrapericardial pressure to rise (>15 mm Hg), which causes compression of all the cardiac chambers. ¡ As tamponade progresses, intracardiac pressures continue to increase, and various clinical symptoms and signs may result. ¡ In severe cases, cardiac tamponade may reduce total venous return, cardiac chamber size, cardiac output, and BP. • Cardiac tamponade may be acute or subacute, depending on the speed with which the pericardial fluid accumulates and exceeds the pericardium’s capacity to expand. ¡ The quantity of fluid required to cause tamponade varies. ¡ When pericardial fluid accumulates rapidly, as little as 200 mL can cause tamponade. ¡ For slowly developing pericardial effusions, more than 2,000 mL may be needed to produce tamponade. CLINICAL ASSESSMENT • History ¡ Cardiac tamponade is most commonly caused by neoplastic disease, renal failure, blunt chest trauma,
Lendell Richardson is medical director and an associate professor in the PA program at Midwestern University in Downers Grove, Ill. The author has disclosed no potential conflicts of interest, financial or otherwise. Dawn Colomb-Lippa, MHS, PA-C, department editor DOI: 10.1097/01.JAA.0000455653.42543.8a Copyright © 2014 American Academy of Physician Assistants
50
www.JAAPA.com
or idiopathic pericarditis. However, tamponade may result from any condition causing pericardial effusion or hemorrhage into the pericardium. An appropriate history should include questions about: t Chest pain t Syncope or presyncope t Any history of pericarditis, cancer, or infectious processes such as tuberculosis t History of renal disease t Trauma or recent invasive medical procedures t Serious bleeding disorders t Hypersensitivity or autoimmunity (such as rheumatic fever, systemic lupus erythematosus, collagen vascular disease, or drug-induced) t Acute myocardial infarction, which can be associated with left ventricular free-wall rupture or hemorrhagic pericarditis. ¡ In acute tamponade, patients may present with chest pain, tachypnea, dyspnea, cool extremities, and peripheral cyanosis. ¡ In subacute tamponade, patients may be asymptomatic early but later may develop dyspnea, edema, chest discomfort, and fatigue.
QUESTIONS 1. The diagnosis of cardiac tamponade is best confirmed by which of the following? a. low voltage (diffuse) on ECG b. chest radiograph showing cardiomegaly c. presence of pericardial effusion on echocardiogram d. hemodynamic and clinical response to pericardial fluid drainage e. electrical alternans on ECG 2. Which finding below is most likely to be present in a patient with cardiac tamponade? a. sinus tachycardia b. pericardial friction rub c. pulsus paradoxus d. peripheral cyanosis e. acute myocardial infarction
Volume 27 • Number 11 • November 2014
Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Cardiac tamponade
JAAPA Journal of the American Academy of Physician Assistants
TREATMENT • Definitive treatment of cardiac tamponade is removal of the pericardial fluid. ¡ Most patients require early drainage. ¡ Patients who exhibit clear hemodynamic compromise will need urgent fluid removal. ¡ Patients with cardiac tamponade but minimal or absent hemodynamic compromise can be safely treated conservatively with serial echocardiograms, careful hemodynamic monitoring, avoidance of volume depletion, and treatment of the underlying cause of the effusion. ¡ Pericardial fluid drainage is required for patients with refractory cardiac tamponade (those initially treated conservatively—whose symptoms worsen, or whose effusions enlarge). • Pericardial fluid can be removed in three ways: ¡ Percutaneous drainage (pericardiocentesis) ¡ Open surgical drainage with or without pericardiectomy (pericardial window) ¡ Video-assisted thoracoscopic pericardiectomy.
Answers
DIAGNOSIS • Electrocardiogram (ECG) ¡ sinus tachycardia ¡ may show low voltage (diffuse) ¡ may show electrical alternans (amplitude of QRS complexes varies from one beat to the next); a fairly specific finding for cardiac tamponade but not very sensitive. • Chest radiograph ¡ In subacute cardiac tamponade, which develops slowly, the cardiac silhouette is enlarged; lung fields are clear. ¡ In contrast, cardiomegaly is usually absent in acute tamponade because at least 200 mL of pericardial fluid must accumulate before the cardiac silhouette enlarges. • Echocardiogram (two-dimensional and Doppler) ¡ Enables the clinician to identify the presence of pericardial effusion and to determine its hemodynamic significance ¡ May show pericardial effusion, cardiac chamber collapse, a dilated inferior vena cava, or respiratory variations in cardiac blood volumes and flow rates. In combination, these abnormalities would be highly suggestive of cardiac tamponade. However, these findings do not confirm the diagnosis. t Cardiac tamponade is a clinical diagnosis. Suspected cases of cardiac tamponade can only be confirmed by hemodynamic and clinical response to pericardial fluid drainage.
• Cardiac CT and cardiovascular MRI are not typically required in the workup of pericardial effusion if echocardiography is available.
1. D. Although each of the abnormal test findings listed may be seen in patients with cardiac tamponade, they are only suggestive, or supportive, of the diagnosis. Because cardiac tamponade is a clinical diagnosis, clinical and hemodynamic response to pericardial fluid drainage confirms the diagnosis. 2. A. Of the findings listed, the most common in patients with cardiac tamponade is sinus tachycardia (elevated jugular venous pressure is also very common). Sinus tachycardia is seen in almost all patients with this disorder; however, its presence is not specific for tamponade. In addition, although electrical alternans is pathognomonic for cardiac tamponade, as it reflects the heart swinging within a large effusion, it is actually only present occasionally.
• Physical examination ¡ Sinus tachycardia (present in almost all patients with cardiac tamponade)—helps to maintain cardiac output ¡ Beck triad (three principal features of tamponade): hypotension, jugular venous distension (indicating elevated jugular venous pressure), and muted or distant heart sounds ¡ Low or narrow pulse pressure (the difference between systolic and diastolic BPs). Normal pulse pressure is 30 to 40 mm Hg. ¡ Pulsus paradoxus (a decline of 10 mm Hg or more in systolic BP on inspiration) is common ¡ Pericardial friction rub may be heard due to inflammation of the pericardium.
www.JAAPA.com
Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
51
Cardiac tamponade Lendell Richardson, MD
GENERAL FEATURES • Cardiac tamponade is a compressive syndrome that affects the heart. Significant fluid accumulation in the pericardial space can cause serious obstruction of blood flow into the ventricles. • The normal pericardial sac contains only a thin layer of pericardial fluid. Under usual circumstances, this sac can stretch to accommodate physiologic changes in cardiac volume. ¡ Once the pericardium’s reserve (or potential) volume is exceeded, the sac stiffens and becomes much less compliant. ¡ When the pericardium markedly stiffens, even small amounts of fluid accumulation can result in cardiac tamponade. ¡ This causes intrapericardial pressure to rise (>15 mm Hg), which causes compression of all the cardiac chambers. ¡ As tamponade progresses, intracardiac pressures continue to increase, and various clinical symptoms and signs may result. ¡ In severe cases, cardiac tamponade may reduce total venous return, cardiac chamber size, cardiac output, and BP. • Cardiac tamponade may be acute or subacute, depending on the speed with which the pericardial fluid accumulates and exceeds the pericardium’s capacity to expand. ¡ The quantity of fluid required to cause tamponade varies. ¡ When pericardial fluid accumulates rapidly, as little as 200 mL can cause tamponade. ¡ For slowly developing pericardial effusions, more than 2,000 mL may be needed to produce tamponade. CLINICAL ASSESSMENT • History ¡ Cardiac tamponade is most commonly caused by neoplastic disease, renal failure, blunt chest trauma,
Lendell Richardson is medical director and an associate professor in the PA program at Midwestern University in Downers Grove, Ill. The author has disclosed no potential conflicts of interest, financial or otherwise. Dawn Colomb-Lippa, MHS, PA-C, department editor DOI: 10.1097/01.JAA.0000455653.42543.8a Copyright © 2014 American Academy of Physician Assistants
50
www.JAAPA.com
or idiopathic pericarditis. However, tamponade may result from any condition causing pericardial effusion or hemorrhage into the pericardium. An appropriate history should include questions about: t Chest pain t Syncope or presyncope t Any history of pericarditis, cancer, or infectious processes such as tuberculosis t History of renal disease t Trauma or recent invasive medical procedures t Serious bleeding disorders t Hypersensitivity or autoimmunity (such as rheumatic fever, systemic lupus erythematosus, collagen vascular disease, or drug-induced) t Acute myocardial infarction, which can be associated with left ventricular free-wall rupture or hemorrhagic pericarditis. ¡ In acute tamponade, patients may present with chest pain, tachypnea, dyspnea, cool extremities, and peripheral cyanosis. ¡ In subacute tamponade, patients may be asymptomatic early but later may develop dyspnea, edema, chest discomfort, and fatigue.
QUESTIONS 1. The diagnosis of cardiac tamponade is best confirmed by which of the following? a. low voltage (diffuse) on ECG b. chest radiograph showing cardiomegaly c. presence of pericardial effusion on echocardiogram d. hemodynamic and clinical response to pericardial fluid drainage e. electrical alternans on ECG 2. Which finding below is most likely to be present in a patient with cardiac tamponade? a. sinus tachycardia b. pericardial friction rub c. pulsus paradoxus d. peripheral cyanosis e. acute myocardial infarction
Volume 27 • Number 11 • November 2014
Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Cardiac tamponade
JAAPA Journal of the American Academy of Physician Assistants
TREATMENT • Definitive treatment of cardiac tamponade is removal of the pericardial fluid. ¡ Most patients require early drainage. ¡ Patients who exhibit clear hemodynamic compromise will need urgent fluid removal. ¡ Patients with cardiac tamponade but minimal or absent hemodynamic compromise can be safely treated conservatively with serial echocardiograms, careful hemodynamic monitoring, avoidance of volume depletion, and treatment of the underlying cause of the effusion. ¡ Pericardial fluid drainage is required for patients with refractory cardiac tamponade (those initially treated conservatively—whose symptoms worsen, or whose effusions enlarge). • Pericardial fluid can be removed in three ways: ¡ Percutaneous drainage (pericardiocentesis) ¡ Open surgical drainage with or without pericardiectomy (pericardial window) ¡ Video-assisted thoracoscopic pericardiectomy.
Answers
DIAGNOSIS • Electrocardiogram (ECG) ¡ sinus tachycardia ¡ may show low voltage (diffuse) ¡ may show electrical alternans (amplitude of QRS complexes varies from one beat to the next); a fairly specific finding for cardiac tamponade but not very sensitive. • Chest radiograph ¡ In subacute cardiac tamponade, which develops slowly, the cardiac silhouette is enlarged; lung fields are clear. ¡ In contrast, cardiomegaly is usually absent in acute tamponade because at least 200 mL of pericardial fluid must accumulate before the cardiac silhouette enlarges. • Echocardiogram (two-dimensional and Doppler) ¡ Enables the clinician to identify the presence of pericardial effusion and to determine its hemodynamic significance ¡ May show pericardial effusion, cardiac chamber collapse, a dilated inferior vena cava, or respiratory variations in cardiac blood volumes and flow rates. In combination, these abnormalities would be highly suggestive of cardiac tamponade. However, these findings do not confirm the diagnosis. t Cardiac tamponade is a clinical diagnosis. Suspected cases of cardiac tamponade can only be confirmed by hemodynamic and clinical response to pericardial fluid drainage.
• Cardiac CT and cardiovascular MRI are not typically required in the workup of pericardial effusion if echocardiography is available.
1. D. Although each of the abnormal test findings listed may be seen in patients with cardiac tamponade, they are only suggestive, or supportive, of the diagnosis. Because cardiac tamponade is a clinical diagnosis, clinical and hemodynamic response to pericardial fluid drainage confirms the diagnosis. 2. A. Of the findings listed, the most common in patients with cardiac tamponade is sinus tachycardia (elevated jugular venous pressure is also very common). Sinus tachycardia is seen in almost all patients with this disorder; however, its presence is not specific for tamponade. In addition, although electrical alternans is pathognomonic for cardiac tamponade, as it reflects the heart swinging within a large effusion, it is actually only present occasionally.
• Physical examination ¡ Sinus tachycardia (present in almost all patients with cardiac tamponade)—helps to maintain cardiac output ¡ Beck triad (three principal features of tamponade): hypotension, jugular venous distension (indicating elevated jugular venous pressure), and muted or distant heart sounds ¡ Low or narrow pulse pressure (the difference between systolic and diastolic BPs). Normal pulse pressure is 30 to 40 mm Hg. ¡ Pulsus paradoxus (a decline of 10 mm Hg or more in systolic BP on inspiration) is common ¡ Pericardial friction rub may be heard due to inflammation of the pericardium.
www.JAAPA.com
Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
51
