Cardiology Week 8 Scq Study Guide Questions

CARDIOLOGY WEEK 8 Saq STUDY GUIDE QUESTIONS a. List THREE causes of cardiac tamponade. b. How can proximal aortic dissection lead to a cardiac tamponade? c. Why are cardiac tamponade patients more likely to experience symptomps of right heart failure? d. Apart from collapsing of the left heart champers, decreased cardiac output and low organ perfusion, why can dyspnea be seen in such patients? e. Explain the mechanism behind why on aucsculations cardiac tamponade patients will distant and muffled heart sounds. f. Explain the concept of pulses paradoxus. g. Discuss the step wise approach for a patient with a cardiac tamponade. Answer: a. 1. Post-MI 2. Proximal aortic dissection. 3. Trauma: could be a penetrating trauma, trauma from a PCI or a trauma from a CABG. b. This is because blood can flow retrogradely and thus get into the pericardial cavity. c. This is because thinner walls of the heart are more likely to get collapsed. As the free wall of the right side of the heart is the thinnest, it is more likely to collapse -> cause a lesser lumen and more pressure within the cavity of the RV chamber -> blood will backflow into the SVC and IVC -> JVD, ascites, hepatomegaly and peripheral edema. d. This is because when the patient takes in deep breaths, this will cause the volume of the intrathoracic cavity to increase and thus will cause the pressure within the intrathoracic cavity to decrease. This will cause the right side of the heart to suck more blood from IVC and the SVC, this will increase the preload to the heart. This will be taken as a compensatory mechanism, so since the body will want to pioritsing doing whatever it takes, to increase preload and thus cardiac output, there will be many more frequent episodes of deep breathes, and hence the dyspnea. e. Since there would be increase fluid accumulation within the pericardical cavity, this means that heart sounds will need to flow the heart cambers, myocardium and through the enlarged pericardial cavity full of fluid -> this will decrease the intensity of the heart sounds -> muffled and distant heart sounds. f. Normally, when a healthy subject inspires there is an increase in blood return/preload to the heart as there an increase in the intrathoracic volume and thus a decrease in the intrathoracic pressure, so more blood from the IVC and SVC will be pulled into the right atrium. Because of the increased volume in the RV this will cause the septum to slightly be pushed more towards the cavity of the left ventricle. This will mean that the space for blood to fill, will be slightly less, so there will be less SV and thus less CO so less BP. However, in a patient with cardiac tamponade because there is an already a squeeze on the LV from the fluid accumulation in the pericardial cavity, the push of the interventricular septum will further decrease the space of the LV cavity for blood filling. As a result, between inspiration and expiration a difference of blood pressure of more than 10 mmHg may be noted. g. 1. Pericardiocentesis: drain fluid from the pericardial cavity until the patient can be stabilised and give the patient IV fluids to increase their blood volume. If the symptoms improve, that is there is an increase in venous return to the heart and thus a greater blood volume and EDV and a higher CO this confirms the diagnosis of a cardiac tamponade. 2. Give the patient vasopressors such as epinephrine and norepinephrine. However, norepinephrine is better, because it has a stronger effect on both the beta 1 receptors of the heart and the alpha 1 receptor on the vessels. These will help increase the heart rate and contractility (b1 receptor antagonism) and cause vasoconstriction (through alpha 1 agonism) of the veins IVC and SVC which will cause less blood pooling into the periphery and more blood being returned to the heart. This will increase blood volume. Together these two effects will increase the cardiac output, increase blood pressure and organ perfusion. 3. Avoid a decrease in the intrathoracic pressure -> AVOID INTUBATING THE PATIENT -> this will take away the physiological compensatory mechanisms. 4. Pericardiocentesis: keep draining the fluid via placing a drain via a pericardial window (interm). 5. Figure out what the cause is and manage it. 1. a) b) c) d) e) List TWO pathogens that are associated with an increased risk of developing pericarditis. (1 mark). What is the main difference between pericardial effusion and cardiac tamponade? Patients with pericardial effusion have pleuritic 1pain. Explain what that means and its’ mechanism of action. In what position is pain made worse? Explain. Describe Ewart’s sign. Answer: a) SARs-COV2 and COX-B. b) A pericardial effusion is when there is fluid accumulation that happens over a long period of time and is slower. Cardiac tamponade happens very suddenly and very fast. Though not all pericardial effusions may progress into cardiac tamponade, most of them do. c) As the patient inspires there lungs will expand outwards towards the periphery to the chest and inwards centrally towards the heart in order to increase the volume of the lungs to be able tp get as much air in as possible. the central expansion of the lungs that happens towards the heart, will squeeze on the heart and thus the pericardium and thus cause pain, as the heart and pericardium may be inflamed. d) The pain is made worse lying down. This is because when someone is in supine position the diaphragm will push on the pericardium and thus make the pain worse. e) Ewart’s sign consist of presence of bronchial sounds only and no visceral breath sounds, vocal/tactile fremitus and dullness to percussion.