Cardiology Flashcards
Syncope and dyspnoea
Aortic stenosis.
- Aortic stenosis refers to the narrowing of the aortic valve. This causes reduced cardiac output and increased left ventricle pressure.
- With exertion, the heart cannot increase cardiac output because of a narrow aortic valve. This can cause syncope due to insufficient perfusion to the brain when it needs the extra oxygen. Syncope is a hallmark sign of aortic stenosis.
Aortic regurgitation, mitral stenosis, and mitral regurgitation do not cause syncope
EKG
- V2 is placed on the fourth intercostal space to the left of the sternum.
- V1, is placed on the fourth intercostal space to the right of the sternum.
- V6, is placed on the fifth intercostal space, at the midaxillary line.
- V5 is placed halfway between V4 and V6 but is not directly next to V6.
Third heart sound
- S3 occurs immediately after S2. It has a very low pitch compared to the S2. and has been described as a ventricular “gallop”. It can occur normally in people under 40 and in athletes. Later in life, it may indicate heart failure (ventricular dysfunction) and/or fluid overload.
- Incorrect: Split S2 is when the pulmonary valve closes slightly after the aortic valve. This normally occurs on inspiration, due to the increased pressure in the pulmonary circulation. It may also be caused by septal defects, pulmonary stenosis, or other abnormalities.
- Incorrect: A split S1 occurs when the closure of the mitral valve is slightly delayed. This is caused by a dysfunction in conduction.
- Incorrect: A murmur due to aortic regurgitation has a high pitch, not very low, and is described as a decrescendo during early diastole.
ventricular tachycardia
- Electrolyte imbalances that are common causes of ventricular tachycardia are hypomagnesemia (low magnesium), hypokalemia (low potassium), and hyperkalemia (high potassium).
- Incorrect: Calcium imbalances may cause QT and ST changes, but not typically ventricular tachycardia.
- Incorrect: Sodium imbalances do not cause arrhythmias.
atrial fibrillation
- In atrial fibrillation, no P waves can be identified because the sinoatrial (SA) node is not the origin of the electrical impulse.
- In atrial fibrillation, multiple areas inside the atria of the heart fire off electrical impulses, preventing the atria from beating effectively, instead only “quivering.”
The result is an atrial rate that is sometimes as high as 600bpm, but the beats have a low amplitude and are too fast to see properly on an EKG.
•As these multiple electrical impulses travel to the atrioventricular (AV) node, the ventricles are stimulated to contract. These random electrical impulses cause the ventricles to squeeze, causing the ventricular rate to increase to 100-200bpm and the irregular intervals of QRS waveforms on an EKG.
Atrial tachycardia and ventricular tachycardia typically exhibit regular QRS intervals.
Ventricular fibrillation does not exhibit regular or identifiable wave forms.
CHF
• Patients with CHF should avoid foods high in sodium such as steak sauce. Monitoring/limiting sodium intake is important to help reduce fluid retention. CHF patients should also weigh themselves daily to help monitor fluid retention, which can exacerbate CHF symptoms
The nurse is caring for a patient suspected to have pulmonary edema. The nurse notes bilateral crackles, orthopnea, edema, and shortness of breath. After notifying the physician, the nurse should avoid which of the following while waiting for the physician to arrive?
- This patient is showing signs of pulmonary edema caused by left-sided heart failure.
- Elevating the patient’s legs would increase venous return. This could overload the heart and worsen the patient’s condition.
- This question asked you to identify the action the nurse should avoid, so the following are incorrect options:
- Incorrect: High-Fowler’s position would improve the patient’s ventilation.
- Incorrect: Supplemental oxygen would help improve the patient’s oxygenation.
- Incorrect: Diuretics would help reduce pulmonary edema and fluid overload.
The nurse is caring for a patient with unstable ventricular tachycardia (VT) who is undergoing immediate synchronized cardioversion. After two unsuccessful shocks, the patient becomes pulseless. What is the nurse’s priority action?
•If a patient becomes pulseless during synchronized cardioversion, immediate unsynchronized defibrillation should occur.
Incorrect:
- If a patient becomes pulseless during synchronized cardioversion, is not appropriate to synchronize the shock again.
- While magnesium sulfate is a medication that may be used during synchronized cardioversion, considering using this medication is not the priority action when a patient become pulseless during synchronized cardioversion.
- Transcutaneous pacing will not be performed if a patient becomes pulseless during synchronized cardioversion.
dysrhythmia
Dysrhythmias can occur when there are disturbances from the three mechanisms of the heart: automaticity, conduction, and re-entry of impulses.
Dysrhythmias can severely decrease the heart’s ability to pump effectively, even causing death.
The most serious complication of dysrhythmia is not myocardial infarct. The most serious complication of a dysrhythmia is asystole, which can cause sudden death.
aortic dissection
- Deep palpation of the abdomen may cause aortic rupture. The nurse should never perform deep palpation on a patient with an aortic dissection or AAA.
- Incorrect: The nurse should inspect the abdomen for ecchymosis, including turning the patient toward the side to inspect the back for any ecchymosis.
- Incorrect: The nurse should also auscultate the aorta for bruits.
evidence of peripheral vascular disease (PVD)
- The ankle brachial index (ABI) is the blood pressure ratio between the lower legs and the arms. Blood pressure in the lower legs is normally higher than the arms, and abnormalities indicate narrowing of arteries. Clinical findings that may suggest the presence of PVD include a history of angina with activity, intermittent claudication, and abnormal (weak or absent) pedal pulses.
- The formula for ABI is the systolic blood pressure of the ankle (measured at the dorsalis pedis or posterior tibial arteries) divided by the systolic pressure in the arms. It is measured on both sides.
- A ratio under 1.0 indicates peripheral vascular disease.
- Incorrect: Allen’s test is used to assess blood supply to the hand.
- Incorrect: Cardiac stress tests are used to measure the heart’s ability to respond to stress.
- Incorrect: Echocardiogram evaluates the structure and function of the heart muscle, but does not tell if there is peripheral vascular disease present.
Angina pectoris
- Angina pectoris is caused by increased oxygen demand and decreased oxygen supply to the heart. With activity, cardiac output and oxygen demand increases. Without an adequate oxygen supply to the heart, ischemia and pain develop.
- Angina is usually self-limiting and often lasts for only 10 or 15 minutes. Pain is usually brought on by activity (such as walking) and ceases after resting.
- Patients may have chest pain related to eating (heartburn) and breathing (pleurisy), but this is generally not related to angina pectoris.
Uncontrolled atrial fibrillation. Determine adequate stroke volume
- A pulse deficit is when the apical pulse is greater than the radial pulse. This is due to a low stroke volume in which most of the blood flow is not reaching the periphery.
- Incorrect: A widening pulse pressure would not be expected. Instead, the nurse would assess for a narrow pulse pressure (when the difference between the systolic and diastolic pressures is less than 25% of the systolic value).
- Incorrect: Corrigan’s pulse is associated with increased stroke volume and decreased peripheral resistance.
- Incorrect: O’Connor’s pulse is not a real condition.
Patient with severe heart failure and coronary artery disease has decreased preload. Causes
- Preload is determined by how much the muscles of the heart stretch due to the blood volume that has filled the ventricles at the end of diastole. Preload is decreased by conditions that reduce circulating volume or venous return. This includes hemorrhage, sepsis, and anaphylaxis.
- Incorrect: Fluid overload and heart failure increase the circulating volume and preload.
- Incorrect: A slower heart rate increases filling time which increases the amount of blood that fills the ventricles and increases preload.
Mitral stenosis
- Mitral stenosis is a narrowing of the mitral orifice and thickening of the mitral valve leaflets, which impedes blood flow into the left ventricle. Blood picks up oxygen in the lungs and re-enters the heart into the left atrium, then must pass through the narrowed and thickened mitral valve into the left ventricle of the heart. The left ventricle is the main chamber, which pumps oxygen-rich blood to the body through the aorta.
- As blood strains to pass through the mitral valve, pressures rise in the left atrium and then in the lungs, where the blood meets vascular resistance as it backs up. This causes pulmonary congestion and shortness of breath, which is worse with activity (as oxygen needs increase).
- If untreated, the pressure and fluid buildup in the lungs increases the workload of the right side of the heart, which has to pump harder to send blood into the lungs to be oxygenated. Over time, right-sided heart failure develops. Complications include secondary pulmonary hypertension, atrial fibrillation, and thrombus.
- Symptoms associated with mitral stenosis include fatigue (especially with activity), edema in the arms and legs (as right-sided heart failure develops), coughing (sputum may be blood- tinged), chest pain, and palpitations. A third heart sound may be heard on auscultation, and patients often have a low oxygen saturation even with supplemental 02. it is diagnosed by echocardiography.
- The most common cause of mitral valve stenosis is rheumatic heart disease caused by rheumatic fever, which can develop after a strep infection (strep throat).
- Incorrect: Fluid overload of the pulmonary circulation can impair gas exchange, potentially leading to respiratory acidosis as CO2 builds up.
- Incorrect: Hypoventilation refers to slow breathing. Patients with mitral stenosis have shortness of breath from pulmonary congestion, which often contributes to faster breathing to compensate.
