Cardiac Tamponade Jonathan E Karademos, MD Emergency Medicine, PGY-1 Thomas Jefferson University Hospital

Objectives What is Cardiac Tamponade How does it happen Clinical Findings Timing Ultrasound Findings

What is it? Slow or rapid compression of the heart due to pericardial accumulation of fluid or gas. Leads to hemodynamic instability.

Pathophysiology Increasing intrapericardial pressure Pericardium stretches until reserve volume is exceeded (happens slowly and It is why acute effusions are so dangerous) The heart then must compete with the increasing pericaridal contents within a fixed space. Heart chambers become smaller, diastolic compliance is reduced. Venous return progressively shifted to systole as the peak associated with early diastolic filling diminishes. Progressively worse as pericardial pressure becomes higher than ventricular diastolic pressures.

Beck’s Triad Hypotension Jugular Venous Distension Muffled/Distant Heart Sounds

Beck’s Triad Hypotension Jugular Venous Distension Muffled/Distant Heart Sounds Present in 1/3 of cases

Clinical Findings Nonspecific symptoms and physical exam findings Tachypnea Dyspnea on Exertion progressing to air hunger at rest Tachycardia Muffled heart sounds Hypotension Shock (cool extremities in rapid tamponade) Jugular venous distension Pulsus paradoxus (inspiratory drop in systolic pressure of 10 mm Hg). Pericardial Rub (if inflammatory cause) Tachycardia in all except early tamponade and hypothyroidism

Timing Is Key Acute Subacute Low pressure (occult) Regional

Lab Studies CXR: Need 200ml of fluid before cardiac silhouette is affected Lateral may show pericardial-fat lines (uncommon but specific) EKG: Sinus tachycardia May show electrical alternation Low voltages Echocardiography: Principle tool for diagnosis. CT MRI: Takes too long Low voltages: present in 60% with tamponade but not present w/o.

Signs on Ultrasound Presence of pericardial effusion (there are exceptions) Chamber collapse Right atrial wall during end diastole Right ventricular collapse during early diastole Left atrium Left Ventricle (most specific) IVC dilation with loss of respiratory variations Respiratory variations >25% in mitral, aortic, and/or tricuspid flow. Exceptions: Mediastinal Mass or Large b/l pleural effusions

Pericardial Effusion Anechoic stripe surrounding heart. 50 mL of fluid, acutely, can cause tamponade Small effusions will not surround the heart and can be seen in the most dependent area of the pericardial space. Can be loculated (post-Cardiac surgery patients) Pericardial fat pad appears as isolated anechoic area with brighter speckles on anterior surface. Don’t confuse with pleural effusions.

Pericardial and Pleural Fluid

Chamber Collapse Make sure it is during diastole (opening of mitral valve) With increasing pericardial pressures, the lower pressures on the right side of the heart are affected first. Can use M-mode with cursor across anterior leaflet of mitral valve and across either right atrial or ventricular free wall. Left atrial collapse seen in 25% with hemodynamic compromise (very specific)

IVC Dilation Sign of increased central venous pressure (CVP) IVC that is greater than 2 cm and collapses less than 50% with inspiration (forced sniff), correlates with CVP greater than 10 cm H2O Present in majority of patients requiring pericardial drainage Highly sensitive but not specific

Mitral Valve Inflow Normal variation in flow across valves due to respiratory cycles. During inspiration, septa move leftward. Reversed during expiration. During cardiac tamponade, this variation in blood flow is exaggerated. Can measure velocities of flow across valves (best in apical view). During cardiac tamponade: Mitral flow variation usually exceeds 30% Tricuspid valve flow usually exceeds 60% Measured in first beat of inspiration and expiration. Can be obscured in severe hypovolemia or right ventricular hypertrophy

Mitral Valve Inflow Ultrasound Podcast

Treatment IV Fluids Pericardiocentesis Scope of another lecture

Conclusions Signs and symptoms can be nonspecific US is a beneficial tool in the confirmation of cardiac tamponade Ultimately, a clinical diagnosis

References Spodick, David H., M.D.,D.Sc. “Acute Cardiac Tamponade” N Engl J Med 2003;349:684-90 ”Cardiac Tamponade”. Sinai EM Ultrasound. http://sinaiem.us/2012/01/30/cardiac-tamponade/ Accessed 7 Dec 2016. Goodman, Adam et al. “The Role of Bedside Ultrasound in the Diagnosis of Pericardial Effusion and Cardiac Tamponade.” Journal of Emergencies, Trauma, and Shock 5.1 (2012): 72–75. PMC. Web. 10 Dec. 2016. ”Diagnosis and Treatment of Pericardial Effusion”. UpToDate. http://bit.ly/2hlNGZa Accessed 11 Dec 2016. ”Tamponade”. Standford Univeristy: Echocardiography in ICU. https://web.stanford.edu/group/ccm_echocardio/cgi- bin/mediawiki/index.php/Tamponade Accessed 11 Dec 2016. Diastology archives. (2016, September 30). Retrieved October 3, 2016, from Ultrasound Podcast, http://www.ultrasoundpodcast.com/tag/diastology/