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.