Quiz 3 Flashcards
What is a re-entrant arrhythmia?
Normally, electrical waves stop propagating when they encounter unexcitable tissue, re-entry occurs when the wave form does not extinguish as it continues to find excitable tissue.
What is considered a hypertensive emergency or crisis?
Direct acute organ damage, often with a BP greater than 180/110. It causes severe vessel damage.
When does sudden cardiac arrest occur?
When there is an abrupt cessation of ventricular function due to rapid ventricular tachycardia or ventricular fibrillation. It is fatal 90% of the time.
How fast does brain damage and brain death occur within sudden cardiac arrest start?
Within 4-6 minutes, and it is reversible in most individuals if it is treated within minutes with CPR and defibrillator. A victim’s chances of survival are reduced by 7-10% per minute without CPR and defibrillator.
Metoprolol
Beta-1 antagonist used to lower blood pressure, angina, glaucoma. Effects include decreased HR and contractility, increased TPR because of beta-2 blockage in skeletal muscle (seems counterintuitive, what decreased HR is more important factor), decreased renin release, bronchial constriction, decreased glycogenolysis in response to hypoglycemia, decreased aqueous humor production. Also used to treat heart failure.
What is an arrhythmia?
Palpitations, irregular heartbeat, premature atrial or ventricular contractions, the most common kind are normal EKG, infrequent, no other heart disease. Can have tachyarrhythmia, which is more serious.
What is a subendocardial infarct?
It is due to hypotension, global ischemia, and is multifocal or diffuse areas of necrosis confined to inner 1/3 to 1/2 of left ventricular wall. Infarct is not necessarily in distribution of one coronary artery. Correlates with Non-ST segment elevation myocardial infarct on EKG, less severe but still potentially lethal.
Dobutamine
This drug is a beta-1 agonist that is used to treat heart failure. Can cause arrhythmias.
What percentage of heart disease deaths does Ischemic heart disease cause in US? (also known as coronary artery disease, or atherosclerotic heart disase)
Causes 70% of US heart disease-deaths and 30% of total mortality.
Chlorthalidone
It is a loop diuretic and it is a thiazide. It inhibits NaCl reabsorption from the luminal side of epithelial cells in the distal convoluted tubule by blocking the Na/Cl transporter. Can also cause hypokalemia, because it increases luminal sodium and thus stimulates the aldosterone-sensitive sodium pump to increase sodium reabsorption in exchange for potassium and hydrogen ions, which are lost to the urine. Also this drug can be inhibited by NSAIDs under certain conditions.
What are the main two causes of calcific aortic valve stenosis?
Post infective endocarditis or rheumatic fever. It is also common in congenital bicuspid valves or normal valves of elderly people.
Definition of cachexia:
The formal definition of cachexia is the loss of body mass that cannot be reversed nutritionally: Even if the affected patient eats more calories, lean body mass will be lost, indicating a primary pathology is in place.
What is liquefactive necrosis?
Liquefactive -See this in infections and, for some unknown reason, in brain infarcts -Due to lots of neutrophils around releasing their toxic contents, “liquefying” the tissue -Gross: tissue is liquidy and creamy yellow (pus) -Micro: lots of neutrophils and cell debris
What is fat necrosis?
Fat necrosis -See this in acute pancreatitis -Damaged cells release lipases, which split the triglyceride esters within fat cells -Gross: chalky, white areas from the combination of the newly-formed free fatty acids with calcium (saponification) -Micro: shadowy outlines of dead fat cells (see image above); sometimes there is a bluish cast from the calcium deposits, which are basophilic
What is caseous necrosis?
Caseous -See this in tuberculosis -Due to the body trying to wall off and kill the bug with macrophages -Gross: White, soft, cheesy-looking (“caseous”) material -Micro: fragmented cells and debris surrounded by a collar of lymphocytes and macrophages (granuloma)
Losartan
This drug is an angiotensin II inhibitor (ACE helps convert angiotensin I to angiotensin II). It decreases peripheral vascular resistance, but has no effect on bradykinin (a potent vasodilator) metabolism and is therefore a more selective blocker of angiotensin effects than ACE inhibitors.
Lovastatin
This drug is a competitive inhibitor of HMG-COA reductase, which helps form cholesterol. These should be avoided during pregnancy. Statins reduce synthesis of cholesterol and have most effect on LDL. These drugs have liver toxicity, and give weakness in skeletal muscles because of increased creatine kinase. If you use them for months, you can have permanent damage to skeletal muscle. This drug is a competitive inhibitor of HMG-COA reductase, which helps form cholesterol. These should be avoided during pregnancy. Statins reduce synthesis of cholesterol and have most effect on LDL. These drugs have liver toxicity, and give weakness in skeletal muscles because of increased creatine kinase. If you use them for months, you can have permanent damage to skeletal muscle.
What is the process of atherosclerosis?
Endothelial injury, then lipid deposits, then inflammation, then fibrosis, then calcification, and this is all mostly in the tunica intima. Then because of this we get slow stenosis which can cause angina and claudication, and then we can get a thrombus/disrupted plaque, where blood flow abruptly stops, we get a myocardial infarct, arrhythmia, sudden cardiac death, and gangrene.
In referring to valvular heart disease, what is stenosis?
A failure to open, prevents forward flow
What are the early events of necrosis?
Cell membrane disruption, Ca++ signal, energy loss.
What is sudden cardiac arrest?
Cardiac arrest, also known as cardiopulmonary arrest or circulatory arrest, is a sudden stop in effective blood circulation due to the failure of the heart to contract effectively or at all. A cardiac arrest is different from (but may be caused by) a myocardial infarction, where blood flow to the muscle of the heart is impaired. It is different from congestive heart failure, where circulation is substandard, but the heart is still pumping sufficient blood to sustain life. Arrested blood circulation prevents delivery of oxygen and glucose to the body. Lack of oxygen and glucose to the brain causes loss of consciousness, which then results in abnormal or absent breathing. Brain injury is likely to happen if cardiac arrest goes untreated for more than five minutes. For the best chance of survival and neurological recovery immediate treatment is important. Cardiac arrest is a medical emergency that, in certain situations, is potentially reversible if treated early. Unexpected cardiac arrest can lead to death within minutes: this is called sudden cardiac death (SCD). The treatment for cardiac arrest is immediate defibrillation if a “shockable” rhythm is present, while cardiopulmonary resuscitation (CPR) is used to provide circulatory support and/or to induce a “shockable” rhythm. A number of heart conditions and non-heart-related events can cause cardiac arrest; the most common cause is coronary artery disease.
Mannitol
It is an osmotic agent. It draws free water out of tissues (including the brain) and into the intravascular space, and can transiently decrease cerebral edema (until excreted by the kidneys). Mannitol is freely filtered in the glomerulus, but cannot be reabsorbed. Thus, it remains in the lumen of the nephron and lowers osmotic pressure. Water then “follows” mannitol into the lumen due to the osmotic pressure.
What kind of lipoproteins are apo-B associated with?
LDLs and VLDLs, the bad ones, lipids induce atherosclerosis, they leak into vessel intima, induce macrophage response/inflammation, the inflammatory response induces smooth muscle cells in intima, fibrosis, calcification, and an atheroma can rupture into lumen and cause a thrombus.
Diltiazem
This drug is a direct vasodilator that reduces calcium influx, is a calcium channel blocker. All the vasodilators that are useful in hypertension relax smooth muscle of arterioles, thereby decreasing systemic vascular resistance. Decreased arterial resistance and decreased mean arterial blood pressure elicit compensatory responses, mediated by baroreceptors and the sympathetic nervous system, and because these are still intact, vasodilator therapies generally do not cause orthostatic hypotension. This drug is also used to treat angina by prevent Ca influx through L-type channels and blocking contraction of smooth and cardiac muscles while reducing O2 demand. Can cause cardiac depression, bradycardia, flushing. This drug is also considered a class IV anti-arrhythmia drug.
What are the best ways to treat angina?
Vasodilation, decreased O2 consumption via beta blockers and calcium channel blockers, nitrates and nitrites (which are metabolized to nitric oxide), which increase smooth muscle relaxation.
What are the main complications of myocardial infarcts, and which are most common?
Most to least common 1. Arrhythmias 2. Congestive heart failure and pulmonary edema 3. Pericarditis 4. Mural thrombosis 5. None 6. Cardiogenic shock 7. Rupture of ventricle or papillary muscle
What is variant or prinzmetal’s angina?
It classically occurs at rest. Brief, like stable angina. Reversible spasm, ST-segment elevation (instead of depression with stable angina).
How do you differentiate a seizure from syncope?
Look for postictal changes with seizures, confusion for 2-10 minutes after seizures.
Definition of metaplasia:
It is the reversible replacement of one differentiated cell type with another mature differentiated cell type. The change from one type of cell to another may generally be a part of normal maturation process or caused by some sort of abnormal stimulus. In simplistic terms, it is as if the original cells are not robust enough to withstand the new environment, and so they change into another type more suited to the new environment.
What is arteriosclerosis vs atherosclerosis?
Arteriosclerosis is the hardening of the arteries. Atherosclerosis is lipid deposits, plaques in arteries, and can cause arteriosclerosis.
What are the systemic symptoms of rheumatic fever?
Polyarthritis of large joints, carditis, subcutaneous nodules, sydenham’s chorea, used to be very common but due to antibiotic treatment for strep throat, not very common anymore.
Spironolactone
This drug is a potassium-sparing diuretic. Most diuretics cause us to lose potassium through urine, sometimes people who take those drugs will also be given a potassium-sparing drug to take with it. This drug prevents K secretion by antagonizing the effects of aldosterone in collecting tubules (via blockade of mineralocorticoid receptors).
What are the consequences of atherosclerosis in the aorta?
Very common in the aorta, most often below the renal arteries, the aorta is usually never occluded complete, but damage to media can cause aneurysm, and can rupture. Abdominal Aortic Aneurysm risk factors include family history, smoking, hypertension, but lipids do not matter for AAA. Ulcerated plaques can embolize.
What is a first degree heart block?
It is a slow but reliable impulse propagation to ventricles, generally not symptomatic, no treatment.
What are the three common causes of hypotension?
- Hypovolemic (low blood volume, blood flows mainly to vital organs) 2. Cardiogenic (heart infarct or failure, arrhythmia, pulmonary emboli 3. Septic shock (overwhelming infection, vasodilation and high permeability, poor cardiac pumping, patient often febrile, flushed, chills, poor prognosis unless infection is rapidly controlled.
What is effusion?
Too much fluid in body cavity, examples are ascites, excess fluid in peritoneal space, pleural effusion, and hydrocephalus, excess cerebrospinal fluid.
What is an atheroma?
It is an accumulation of degenerative material in the tunica intima (inner layer) of artery walls. The material consists of (mostly) macrophage cells, or debris, containing lipids (cholesterol and fatty acids), calcium and a variable amount of fibrous connective tissue. The accumulated material forms a swelling in the artery wall, which may intrude into the channel of the artery, narrowing it and restricting blood flow. Atheroma occurs in atherosclerosis, which is one of the three subtypes of arteriosclerosis.
Necrosis happens more often to individual cells rather than cell clusters. True or False?
False, it is the opposite
Amyl nitrate
Used to treat angina, and this is used for someone who can only breath in the drug instead of swallow. Ampule is crushed and fumes inhaled, it is short acting.
What re the main complications of infective endocarditis?
Cardiac complications, which are coronary artery emboli, abscesses, erosion of valve or chordae tenineae. Non-cardiac complications, which are septic emboli, immune complex diseases in vessels or kidneys.
What is stable angina?
Pain that feels like pressure for 2-5 minutes and associated with exertion. Relieved by rest or vasodilators (nitroglycerine). It is subendocardial ischemia, and you get a ST-segment depression. Usulaly due to fixed coronary stenosis.
Prazosin
This drug is an alpha-1 antagonist. Causes vasodilation and thus decreased TPR and decreased BP. Used to treat hypertension, benign prostatic hypertrophy. Side effects include orthostatic hypotension, nasal congestion.
Mecamylamine
Rarely used, but is a nicoticic neuronal receptor antagonist. It competitively blocks nicotinic cholinoceptors on postganglionic neurons in both sympathetic and parasympathetic ganglia. Causes excessive orthostatic hypotension and constipation, urinary retention, blurred vision, dry mouth, so it has sympathoplegic and parasympathoplegic effects.
What are the main hypertension-induced problems?
Accelerated atherosclerosis due to endothelial injury, myocardial infarcts, stroke, peripheral vascular disease, aneurysms, heart failure, renal failure, retinal and brain damage, hemorrhages.
Which side of the heart gets bigger when body has systemic hypertension?
Left side has to pump harder so it undergoes hypertrophy.
What percent of US adults have hypercholesterolemia levels above 200 mg/dl? 240 mg/dl?
50% and 13%
What is the mechanism behind atherosclerosis?
Endothelial dysfunction (smoking, hypertension, diabetes, lipids, inflammation) then lipids deposit in vessel wall intima, then inflammation/foamy macrophages, which all can do 1 of 2 things, either go to intimal smooth muscle, cause fibrosis, cause fibroatheroma with stenosis, which can lead to angina, claudication, etc, or it can cause plaque ulcer or rupture, which can lead to thrombosis (ruptured or ulcerated plaques), which causes most infarcts and sudden death.
What is a transmural infarct?
It is due to an anuerysm in the heart wall and it has full thickness, endocardium to epicardium. Usually involving left ventricle anterior and posterior free wall or septum with extension into right ventricle wall in 15-30% of cases. More severe than MI, correlates with ST segment elevation myocardial infarct on EKG.
What is a second degree heart block?
It is when impulse propagation to ventricles sometimes fails. You get irregular ventricular contractions, sometimes causes syncope, pacemaker sometimes needed.
How does atherosclerosis cause stenosis and disease?
Resistance to flow is inversely proportional to diameter^4 (i.e. inversely proportional to cross sectional area^2). You must have 75% stenosis (decreased cross sectional area) to clinically impede flow. This increases resistance 16-fold. Slow stenosis causes stable angina while abrupt stenosis or occlusion can cause infarcts/sudden death and is associated with a thrombus or embolus. A rupture/erosion causes a complicated lesion, and is the most common cause of most infarcts.
Where does arteriosclerosis usually happen?
Aorta, coronary arteries, iliac/femoral/and politeal arteries, carotids/circle of willis arteries, kidney, and pulmonary arteries.
Acetazolamide
It is a carbonic anhydrase inhibitor, which will decrease the reabsorption of NaCO3 in the end, because the proton pump isn’t working because CA was blocked, so without that proton pump, less NaCO3 is reabsorbed, and more is secreted, and water will follow. Works in the primary convoluted tubule. It also changes the pH to make urine more basic because not as much acid is being secreted. This drug is used for treating glaucoma, epilepsy.
What are the main symptoms of a myocardial infarct?
Retrosternal chest pain, dyspnea, diaphoresis (sweating), nausea/vomiting, palpitations, anxiety, or can be asymptomatic or present as sudden death.
What is nuclear pyknosis?
Is when the nucleus becomes shriveled and dark.
What are the consequences of atherosclerosis in the peripheral arteries like iliac, femoral, and popliteal arteries?
Causes claudication (ache, pain, fatigue with exertion), then ulcers and ultimately gangrene.
Labetalol
This drug is a beta and alpha-1 antagonist used to treat high blood pressure, angina, glaucoma.
What are the mediators that actually cause angina pectoris?
It is due to ischemia-related metabolites like glucose and other factors.
What are the atherosclerosis main key points?
Exremely common cause of death. Due to endothelial damage, lipid deposits, inflammation, fibrosis/smooth muscle, and rupture or erosion causing thrombosis. Thrombosis (not stenosis) is the main cause of infarcts. Often happens in areas of only mild/moderate stenosis. Stenosis (not thrombosis) is the main cause of predictable pain with exertion, like angina and claudication (leg pain).
Phenoxybenzamine
This drug is a non-selective alpha antagonist.
What is essential hypertension?
No obvious cause, very common, nearly 50 million in US, 95% of all hypertensive patients. Possible causes include increased sodium retention & intravascular volume, narrowing of arteries, high TPR lowers blood pressure in kidneys, kidneys sense lower pressure and signal to retain sodium to increase BP, vicious cycle.
What are the complications of artificial valves?
Thrombosis, can cause thromboembolism, anticoagulant related hemorrhage, increased risk of infective endocarditis, structural or biological deterioration, nonstructural dysfunction-tissue entrapment, paravalvular leaks, anemia, wears out valves and leaks.
What are the four major classes of antihypertensives?
- Diuretics (deplete sodium, reduce blood volume) 2. Sympathoplegics (reduce peripheral vascular resistance) 3. Direct vasodilators (relax vascular smooth muscle, dilating vessels) 4. Anti-angiotensin agents (inhibit action/production of angiotensin and thus reduce peripheral vascular resistance)
Hydralazine
This drug is a direct vasodilator that releases nitric oxide from the drug or from endothelium. All the vasodilators that are useful in hypertension relax smooth muscle of arterioles, thereby decreasing systemic vascular resistance. Decreased arterial resistance and decreased mean arterial blood pressure elicit compensatory responses, mediated by baroreceptors and the sympathetic nervous system, and because these are still intact, vasodilator therapies generally do not cause orthostatic hypotension. Also used to treat heart failure.
How does left-sided heart failure occur and what are the consequences?
It is caused by ischemic heart disease, hypertension, aortic and mitral valve disease, myocardial disease like cardiomyopathy. You get pulmonary edema and breathing problems, dyspnea (breathlessness), orthopnea (dyspnea while lying down due to vascular congestion and it develops within minutes), paroxysmal nocturnal dyspnea (extreme dyspnea, develops over a few hours, due to pulmonary edema from heart failure while lying down). You also get reduced perfusion to organs like kidneys, ending up with prerenal azotemia (high BUN with less high or normal creatinine) or ischemic tubular necrosis.
Nitroglycerin
Allows nitric oxide to float around in the body causing vasodilation to the arteries of the heart, treating angina and chest pain, it also decreases myocardial O2 consumption. They have long-lasting patches for 8 hours, and it is volatile, needs to be stored in closed glass container. Side effects include orthostatic hypotension, tachycardia (reflex), throbbing headache. Tolerance develops rapidly.
Phentolamine
This drug is a non-selective alpha antagonist
What percentage of patients with a history of myocardial infarctions have arrhythmias?
80%, because of all of the scar tissue there.
When we get severe stenosis in coronary arteries, in what layer of the vessels do most changes take place?
Tunica Intima
