Cardiac – Heart disease/hypertension/Myocardial Infarction/fluid control/renal/sickle cell. Flashcards
What is the main concept of fluid balance?
Fluid balance involves maintaining the proper amount of water and electrolytes in the body, which is crucial for normal cell and organ function. It includes the intake, distribution, and output of body fluids.
What are the primary compartments of fluid in the human body?
Intracellular fluid (ICF): 28L within the cells.
Extracellular fluid (ECF): 11L surrounding the cells, of which 3L is plasma and 8L is interstitial fluid.
What is osmolarity?
Osmolarity is the concentration of solutes in a solution, measured as milliosmoles per liter (mOsm/L), which is important for maintaining fluid balance in the body.
What is the difference between isotonic, hypotonic, and hypertonic fluids?
Isotonic: Equal solute concentration inside and outside the cell.
Hypotonic: Lower solute concentration outside the cell, causing water to move into the cell.
Hypertonic: Higher solute concentration outside the cell, causing water to move out of the cell.
What hormones regulate fluid balance?
ADH (Antidiuretic Hormone): Regulates water retention by the kidneys.
Aldosterone: Regulates sodium and water reabsorption in the kidneys.
Atrial Natriuretic Peptide (ANP): Regulates sodium and fluid balance, decreasing blood volume.
How does ADH (Antidiuretic Hormone) work?
ADH is released when blood osmolarity increases or blood volume/pressure decreases. It increases water reabsorption by the kidneys to conserve water and reduce osmolarity.
What triggers thirst in the body?
Thirst is primarily stimulated by:
Hypertonicity: Dehydration causing cellular dehydration.
Hypovolaemia: Low blood volume.
Hypotension: Low blood pressure.
Angiotensin II: Produced in response to low blood pressure or low blood volume.
What is water intoxication?
Water intoxication occurs when excessive fluid intake dilutes extracellular body fluids, causing swelling of cells, which can lead to coma and death. It can be caused by conditions like renal disease or excessive ADH production.
What is the role of aldosterone in fluid balance?
Aldosterone acts on the kidneys to promote sodium and water reabsorption, which increases blood volume and blood pressure. It also helps maintain electrolyte balance, particularly sodium and potassium levels.
What is the Renin-Angiotensin-Aldosterone System (RAAS)?
RAAS regulates blood pressure and fluid balance. When blood volume is low, renin is released from the kidneys, leading to the production of angiotensin II, which stimulates aldosterone release to conserve sodium and water.
What is Diabetes Insipidus?
Diabetes insipidus is a condition characterized by the lack of ADH or resistance to ADH, leading to the production of large volumes of dilute urine and excessive thirst.
What is the Syndrome of Inappropriate ADH Secretion (SIADH)?
SIADH is a condition where excessive ADH production leads to fluid retention, resulting in low sodium levels in the blood (hyponatremia) and potential fluid overload.
What is oedema and its causes?
Oedema is the accumulation of excess fluid in the interstitial spaces. It can result from increased blood pressure, venous blockage, increased capillary permeability, or decreased protein (e.g., in liver disease or malnutrition).
What is the role of capillary transport in fluid dynamics?
Capillaries exchange fluids, ions, and gases between the blood and tissues. Factors like blood pressure, osmotic pressure, and capillary permeability influence the movement of water and solutes across capillary walls.
What is shock?
Shock is an acute circulatory crisis characterized by hypotension and inadequate blood flow, which leads to oxygen and nutrient starvation of tissues, resulting in severe, potentially fatal symptoms.
What is Mean Arterial Pressure (MAP) and why is it important?
MAP = Diastolic BP + 1/3(Systolic BP – Diastolic BP).
A normal MAP is between 70 and 100 mmHg. If MAP drops below 60 mmHg, vital organs may not receive adequate blood supply, while higher MAPs may cause blood clots or heart muscle damage.
What are the main compartments for fluid in the body?
Intracellular Fluid (ICF): Fluid within cells.
Extracellular Fluid (ECF): Includes interstitial fluid and intravascular fluid (plasma).
Third Space: Fluid in non-functional areas like the peritoneal and pleural cavities.
What are the signs and symptoms of shock?
- Low blood pressure (reduced MAP).
- Increased pulse and respiration rate.
- Skin colour changes, anaerobic metabolism, and accumulation of metabolic waste.
- Decreased urine output and altered consciousness.
What are the stages of shock?
Initial Stage: No signs but cellular changes occur.
Compensatory Stage: Physiological adaptations to overcome the issue.
Progressive Stage: Compensatory mechanisms fail, leading to adverse effects.
Refractory Stage: Pathophysiological processes established, leading to death.
What is hypovolemic shock and its causes?
Hypovolemic shock is caused by a significant loss of blood or fluids. It can be due to blood loss (hemorrhage, trauma) or non-blood loss (vomiting, diarrhea, burns, polyuria).
What happens during the stages of hypovolemic shock?
Stage 1: Loss of 15% blood volume, mild symptoms like pale skin and anxiety.
Stage 2: Loss of 30% blood, increased heart rate, sweating, and delayed capillary refill.
Stage 3: Loss of 30-40%, low blood pressure, rapid heart rate, cold skin.
Stage 4: Loss of more than 40%, critical, with very low blood pressure and minimal urine output.
What is the treatment for hypovolemic shock?
Fluid replacement to restore blood volume, blood transfusion if needed, and vasopressors as a last resort to constrict blood vessels and increase blood pressure.
What is cardiogenic shock and its causes?
Cardiogenic shock occurs when the heart is unable to pump effectively due to conditions like heart failure, myocardial infarction, myocarditis, or valve stenosis.
How is cardiogenic shock treated?
Treatment includes improving myocardial function through arrhythmia management, reperfusion therapy (e.g., PCI), and the use of inotropes (e.g., dobutamine) and vasopressors.
What is obstructive shock?
Obstructive shock occurs when there is a blockage in the blood flow, such as in cardiac tamponade, pulmonary embolism, or tension pneumothorax.
How is obstructive shock treated?
Treatment is primarily directed at addressing the underlying obstruction. Once the obstruction is resolved, the patient’s condition often improves.
What is distributive shock and its causes?
Distributive shock occurs when there is an alteration in systemic vascular resistance (SVR), caused by conditions like sepsis, anaphylaxis, or spinal cord injury.
What is sepsis and how is it treated?
Sepsis is an infection leading to widespread inflammation, blood vessel dilation, and reduced SVR. Treatment involves screening for infection, using antibiotics, fluid replacement, and vasopressors (meds that increase bp by narrowing blood vessels) if necessary.
What is anaphylaxis and how is it treated?
Anaphylaxis is a severe allergic reaction leading to widespread edema and airway constriction. It is treated with IM adrenaline (epinephrine), antihistamines, fluid replacement, and airway management.
What is neurogenic shock?
Neurogenic shock results from spinal cord injury, leading to reduced sympathetic nervous system function, causing hypotension and bradycardia, often in patients with injuries above the T6 vertebra.
How is neurogenic shock treated?
Treatment includes aggressive fluid replacement, the use of vasopressors (vaso-constrictors) inotropes, and atropine (increases Heart rate) if bradycardia is present.
What is the primary cause of cardiovascular disease-related deaths in the UK?
Cardiovascular diseases, including coronary heart disease and stroke, are the second leading cause of death in the UK, accounting for approximately ¼ of all deaths.
What is hypertension and what causes it?
Hypertension is high blood pressure caused by factors such as inflammation in blood vessels, insulin resistance, ineffective hormone responses (like renin-angiotensin-aldosterone), vasoconstriction, and renal salt and water retention.
What is myocardial ischemia and its common causes?
Myocardial ischemia occurs when coronary arteries cannot supply enough blood to meet the heart’s metabolic demands, often due to atherosclerosis, leading to conditions like angina, heart failure, and arrhythmias.
What is coronary artery disease and how does it develop?
Coronary artery disease develops slowly through atherosclerosis, where plaques narrow arteries, reducing blood flow. Unstable plaques can rupture, causing thrombosis, which may lead to myocardial infarction, pulmonary embolism, or stroke.
What is angina pectoralis and what triggers it?
Angina pectoralis is chest pain caused by a fixed coronary obstruction. It typically occurs during exertion, stress, or extreme temperatures, and is often associated with atherosclerotic heart disease.
What are the signs of a myocardial infarction (MI) vs. angina?
Symptoms of MI include chest pain lasting more than 5-10 minutes, radiating to the left arm, shoulder, or neck/jaw, and worsening pain at rest. Angina typically subsides with rest and is not as intense.
What is the role of the coronary circulation?
The coronary circulation supplies blood to the heart muscle via the left and right coronary arteries. It is controlled by myocardial oxygen demand, blood pressure, autonomic nervous system regulation, and local metabolic activity.
How does metabolic activity affect coronary blood flow?
As the myocardium works, adenosine is released, which acts as a vasodilator to increase blood flow. The endothelial cells also release substances like nitric oxide (vasodilator) and endothelins (vasoconstrictor).
What is the significance of 70% oxygen usage in myocardial blood flow at rest?
The myocardium uses over 70% of the oxygen supplied to it at rest. During exertion, this demand increases, and any reduction in blood flow (due to disease) can lead to ischemia and myocardial infarction.
What are some common pharmacological treatments for cardiovascular diseases?
- Anticoagulants: Minimize clot formation.
- Nitrates (e.g., GTN): Dilate coronary arteries.
- Beta-blockers: Reduce heart rate and contraction force.
- ACE inhibitors: Regulate blood pressure by causing vasodilation.
- Calcium channel blockers: Control blood pressure.
- Statins: Lower cholesterol and control blood pressure.
- Diuretics: Prevent fluid overload.
What should a normal sinus rhythm look like on an ECG?
A Normal Sinus Rhythm ECG has:
✅ Spike that looks like a SAILBOAT ⛵ = QRS complex
✅ 2 waves between each ⛵ = P wave + T wave
✅ 60-100 BPM
What should a SINUS TACHYCARDIA rhythm look like on an ECG?
SINUS TACHYCARDIA = Spike ⛵ + 2 waves that come fast together. >100 BPM
What should a SINUS BRADYCARDIA rhythm look like on an ECG?
SINUS BRADYCARDIA = Spike ⛵ + 2 waves that are slowed apart. <60 BPM
What should an AFIB rhythm look like on an ECG?
AFIB = Spike ⛵ + choppy or chaotic waves pattern on repeat
What should an AFLUTTER rhythm look like on an ECG?
AFLUTTER = Spike ⛵ + waves cut w/ a sawtooth
What should a VTACH rhythm look like on an ECG?
VTACH = Mountains of HUGE waves🌊🌊 VTACH with pulse = cardiovert
VTACH without pulse = defibrillate
What should a VFIB rhythm look like on an ECG?
VFIB = Pure chaos of waves w/ no spike ⛵. Have the V (VFIB) give the D (defibrillate)
What is the unknown Wave?
P wave = Also known as atrial depolarization
What is the unknown Wave?
QRS wave = Time it takes for the ventricles to depolarize
What is the J point?
Exact point where the ventricular depolarization stops and the ventricular repolarization starts
What is the unknown interval?
PR interval
What is the unknown interval?
QT interval
What is the unknown interval?
ST interval
What is the unknown Wave?
T wave = ventricular repolarization
What are common signs and symptoms of a myocardial infarction - MI (heart attack)?
- Central crushing chest pain (not always)
- Pain radiates to the left arm and jaw (not always)
- Grey color or dusky appearance in darker skin tones
- Cold and clammy to touch
- Nausea
- Breathlessness
- Impending sense of doom
- Silent MI is not uncommon
How might women present during a myocardial infarction (MI)?
Women may present with signs similar to indigestion, which can be easily missed and misdiagnosed as gastrointestinal issues.
What are the key investigations for diagnosing a myocardial infarction?
- 12-lead ECG: Can show STEMI (ST-Elevation Myocardial Infarction) or non-STEMI.
- Blood tests, especially for Troponin levels, which are proteins released from the heart muscle when under stress or injury.
What is the role of Troponin in diagnosing myocardial infarction?
Troponin is a cardiac-specific protein that is released into the blood when the heart muscle is damaged, acting as a marker for myocardial injury.
What is MONA in the context of myocardial infarction treatment?
M - Morphine: Pain relief and reduces heart workload.
O - Oxygen: Increases oxygen delivery to the heart.
N - Nitroglycerin: Relieves chest pain by dilating coronary arteries.
A - Aspirin: Prevents platelet aggregation and reduces clotting.
What role do Anticoagulants play in treating myocardial infarction?
Anticoagulants help reduce clot formation and minimize the risk of a clot traveling from the site of the plaque rupture, which can worsen the myocardial infarction.
What is the purpose of Nitrates in MI treatment?
Nitrates like Glyceryl Trinitrate (GTN), administered sublingually or as a spray, dilate the coronary arteries, improving blood flow to the heart muscle and relieving pain.
How do Beta blockers work in myocardial infarction management?
Beta blockers reduce heart rate and the force of contraction in the left ventricle by blocking the action of adrenaline and nor-adrenaline, thereby decreasing the heart’s oxygen demand.
What is the role of ACE inhibitors in treating myocardial infarction?
ACE inhibitors block the conversion of angiotensin I to angiotensin II, leading to vasodilation, which helps lower blood pressure and reduce heart strain.
How do Calcium channel blockers help manage blood pressure in myocardial infarction?
Calcium channel blockers relax the blood vessels and reduce heart workload by preventing calcium from entering smooth muscle cells in the heart and blood vessels.
What role do Statins play in myocardial infarction treatment?
Statins help lower cholesterol levels and improve vascular health, which is important for managing blood pressure and preventing further cardiovascular events.
What is the role of Diuretics in myocardial infarction management?
Diuretics help maintain fluid balance by removing excess salt and water, preventing fluid overload, and reducing strain on the heart.
What does a raised ST segment on an ECG indicate?
A raised ST segment is a sign of ST-Elevation Myocardial Infarction (STEMI), which is a type of heart attack caused by a blockage in one of the coronary arteries.
What causes the ST segment elevation in an ECG during a myocardial infarction?
ST segment elevation occurs due to reduced blood flow to the heart muscle caused by a blockage in a coronary artery, leading to heart muscle injury.
What are the typical ECG findings associated with a myocardial infarction (MI)?
In the case of a myocardial infarction, you may observe a raised ST segment and possibly a raised T wave, which are classic markers of STEMI and indicate damage to the heart muscle.
What is Atrial Fibrillation (AFIB)?
Atrial Fibrillation (AFib) is a common heart arrhythmia where the heart’s upper chambers (atria) experience chaotic electrical signals, causing irregular and often rapid heartbeats, which disrupt the normal rhythm between the atria and ventricles.
Symptoms include palpitations, shortness of breath, dizziness, and fatigue.
Blood returning from the lungs first flows into the…
left atrium
During atrial systole…
The bicuspid (mitral) valve is open
Blood flows into the coronary arteries from the …
ascending aorta
Which of these rhythms is known as Normal Sinus rhythm?
A(second one down)
What happens during the depolarisation of the atria in the cardiac cycle?
The impulse begins in the SA node and spreads across both atria, causing the P wave and atrial contraction. This impulse moves through the bundle of Bachmann, but it only affects the atria and does not reach the AV node due to fibrous connective tissue that does not conduct the impulse well.
What happens during atrial systole (contraction)?
During atrial systole, around 70% of the blood flows easily into the ventricles, with the remaining 25% being ejected as the atria contract. The atria contract as the P wave finishes, ensuring the final blood volume enters the ventricles.
What happens during the depolarization of ventricular contractile fibres in the cardiac cycle?
The impulse passes through the AV node, causing the QRS complex to appear. The junctional tissue in the AV node delays the impulse by about 0.04 seconds, ensuring the ventricles are full before they contract, allowing the maximum amount of blood (cardiac output) to be ejected in a single heartbeat.
What happens during ventricular systole (contraction)?
During ventricular systole, the bicuspid (mitral) and tricuspid valves close as the ventricles fill, causing the first heart sound (“lub”). The ventricular pressure rises, eventually surpassing that in the aorta and pulmonary artery, causing the semilunar valves (aortic and pulmonary) to open. This allows blood to be ejected from the ventricles. As the ventricles empty, the pressure falls, and the semilunar valves close, producing the second heart sound (“dub”).
What happens during ventricular repolarization in the cardiac cycle?
During ventricular repolarization, the T wave represents the relaxation phase of the ventricles. As the ventricles reset (repolarize), the myocardium relaxes, preparing for the next contraction.
What happens during ventricular diastole (relaxation)?
During ventricular diastole, the pulmonary artery and aortic valves close. Blood from the vena cava and pulmonary veins returns to the heart and flows into the atria. As atrial pressure increases and ventricular pressure falls, the bicuspid and tricuspid valves open, allowing the ventricles to refill. Blood initially flows quickly and then slows as pressures begin to equalize.
