The X axis is labeled using the “scores” of political party order anafranil from india, and because this is a nominal variable cheap anafranil express, they can be arranged in any order purchase anafranil toronto. In the frequency table buy anafranil discount, we see that six people were Republicans, so we draw a bar at a height (frequency) of 6 and so on. Say that the lower graph is from a survey in which we counted the number of partic- ipants having different military ranks (an ordinal variable). Political affiliation Ordinal Variable of 8 Military Rank 7 Party f 6 General 3 5 Colonel 8 f 4 Lieutenant 4 Sergeant 5 3 2 1 0 Sgt. Later we will see bar graphs in other contexts and this same rule always applies: Create a bar graph whenever the X variable is discrete. On other hand, recall that interval and ratio scales are assumed to be continuous:They allow fractional amounts that continue between the whole numbers. Histograms Create a histogram when plotting a frequency distribution containing a small number of different interval or ratio scores. A histogram is similar to a bar graph except that in a histogram adjacent bars touch. For example, say that we measured the number of parking tickets some people received, obtaining the data in Figure 3. Although you can- not have a fraction of a ticket, this ratio variable is theoretically continuous (e. By having no gap between the bars in our graph, we communicate that there are no gaps when measuring this X variable. Polygons Usually, we don’t create a histogram when we have a large number of dif- ferent interval or ratio scores, such as if our participants had from 1 to 50 parking tick- ets. The 50 bars would need to be very skinny, so the graph would be difficult to read. We have no rule for what number of scores is too large, but when a histogram is unwork- able, we create a frequency polygon. Construct a frequency polygon by placing a data point over each score on the X axis at a height corresponding to the appropriate fre- quency. Because each line continues between two adjacent data points, we communicate that our measurements continue between the two scores on the X axis and therefore that this is a continuous variable. Later we will create graphs in other contexts that also involve connecting data points with straight lines. This same rule always applies: Connect adjacent data points with straight lines whenever the X variable is continuous. In this way, we create a complete geometric figure—a polygon—with the X axis as its base. Often in statistics you must a read a polygon to determine a score’s frequency, so be sure you can do this: Locate the score on the X axis and then move upward until you reach the line forming the polygon. To show the number of freshmen, sophomores, and a histogram with a few interval/ratio scores, and a juniors who are members of a fraternity, plot a. To show the number of people preferring chocolate versus females (a nominal variable), create a bar or vanilla ice cream in a sample, plot a. Call it a normal curve or a normal distribution or say that the scores are normally distributed. Because it represents an ideal population, a normal curve is different from the choppy polygon we saw previously. First, the curve is smooth because a population produces so many different scores that the individual data points are too close to- gether for straight lines to connect them. Second, because the curve reflects an infinite number of scores, we can- not label the Y axis with specific frequencies. Simply remember that the higher the curve is above a score, the higher is the score’s frequency. Finally, regardless of how high or low an X score might be, theoretically it might sometimes occur. Therefore, as we read to the left or to the right on the X axis, the frequencies approach—but never reach—a frequency of zero, so the curve approaches but never actually touches the axis. The score with the highest frequency is the middle score between the highest and lowest scores. As we proceed away from the middle score either toward the higher or lower scores, the frequencies at first decrease slightly. Farther from the middle score, however, the frequencies decrease more drastically, with the highest and lowest scores having relatively low frequency. In statistics the scores that are relatively far above and below the middle score of the dis- tribution are called the “extreme” scores. Then, the far left and right portions of a normal curve containing the low-frequency, extreme scores are called the tails of the distribution. The reason the normal curve is important is because it is a very common distribution in psychology and other behavioral sciences: For most of the variables that we study, the scores naturally form a curve similar to this, with most of the scores around the middle score, and with progressively fewer higher or lower scores. Because of this, the normal curve is also very common in our upcoming statistical procedures. Do you see that a score of 15 has a rela- tively low frequency and a score of 45 has the same low frequency? Do you see that there are relatively few scores in the tail above 50 or in the tail below 10? On a normal distribution, the farther a score is from the central score of the distribution, the less frequently the score occurs. A distribution may not match the previous curve exactly, but it can still meet the mathe- matical definition of a normal distribution. Curve A is skinny relative to the ideal because only a few scores around the middle score have a relatively high fre- quency. On the other hand, Curve C is fat relative to the ideal because more scores farther below and above the middle have a high frequency. Because these curves generally have that bell shape, however, for statistical purposes their differences are not critical. Other Common Frequency Polygons Not all data form a normal distribution and then the distribution is called nonnormal. A negatively skewed distribution contains extreme low scores that have a low fre- quency but does not contain low-frequency, extreme high scores. This pattern might be found, for example, by measuring the running speed of professional football players. Most would tend to run at higher speeds, but a relatively few linemen lumber in at the slower speeds. This pattern might be found, for example, if we measured participants’ “reaction time” for recogniz- ing words. Usually, scores will tend to be rather low, but every once in a while a person will “fall asleep at the switch,” requiring a large amount of time and thus producing a high score. Another type of nonnormal distribution is a bimodal distribution, shown in the left- hand side of Figure 3. A bimodal distribution is a symmetrical distribution contain- ing two distinct humps, each reflecting relatively high-frequency scores. High scores scores of each hump is one score that occurs more frequently than the surrounding scores, and technically the center scores have the same frequency. Such a distribution would occur with test scores, for example, if most students scored at 60 or 80, with fewer students failing or scoring in the 70s or 90s. Finally, a third type of distribution is a rectangular distribution, as shown in the right-hand side of Figure 3. There are no discernible tails be- cause the frequencies of all scores are the same. Labeling Frequency Distributions You need to know the names of the previous distributions because descriptive statistics describe the characteristics of data, and one very important characteristic is the shape of the distribution that the data form. Thus, although I might have data containing many different scores, if, for example, I tell you they form a normal distribution, you can mentally envision the distribution and quickly and easily understand what the scores are like: Few scores are very low or very high, with the most common, frequent scores in the middle. Therefore, the first step when examining any data is to identify the shape of the simple frequency distribution that they form. Recognize, however, that data in the real world will never form the perfect shapes that we’ve discussed. Instead, the scores will form a bumpy, rough approximation to the ideal distribution. For example, data never form a perfect normal curve and, at best, only come close to that shape.
What is the most likely quadrant of the buttock generic anafranil 10 mg with mastercard, at the medial fat pad of the knee etiology of the patient’s current infection? She describes years of fatigue purchase anafranil us, chronic pain purchase anafranil 75 mg, poor males discount anafranil 25 mg online, and this difference is maintained throughout sleep, and irritability and is unable to work due to her life. Which of the following should be your ﬁrst severity of rheumatoid arthritis or its extraarticular treatment step? Referral for psychotherapy with a psychologist surfaces incompletely approximate each other E. Which of the following statements is creases friction true regarding the development and treatment of disabil- E. A 35-year-old female presents to her primary care now ﬁrst-line therapy and have been shown to limit doctor complaining of diffuse body and joint pain. The patient complains posture and range of motion is important in limit- of chronic pain and poor sleep quality that she feels is due ing disability. A 45-year-old male has been hospitalized for several lupus erythematosus based upon the presence of polyar- weeks in the intensive care unit for postsurgical compli- thritis, malar rash with photosensitivity, and oral ulcer- cations after gastrojejunal bypass surgery. Initial management of this treatment for the joint symptoms as she feels they limit disorder should include all the following except her activities of daily living. A 43-year-old male presents to your ofﬁce com- lifts items, he describes worsening of the pain and also plaining of weakness in the right hand for 2 days. He re- pain in the left buttock that radiates down the posterior ports that he had been in excellent health until 2 months left thigh. The patient denies pain at rest and any his- ago, when he was diagnosed with hypertension. Which ex- that diagnosis, he has lost 20 lb unintentionally and com- amination maneuver is the most speciﬁc for lumbar plains of frequent headaches and abdominal pain that is disk herniation? Left crossed straight leg raise nation, the patient appears well developed and without E. A 42-year-old woman is being treated with cyclo- ity to extend the right wrist and ﬁngers against gravity. Activation of the complement system with postnasal drip and cough that disrupts her sleep. Binding to cell surface receptors on granulocytes addition, she will also note itchy and watery eyes. When and macrophages to initiate phagocytosis the symptoms occur, she takes nonprescription lorata- C. Nonspeciﬁc binding of antigen for presentation to T dine, 10 mg daily, with signiﬁcant improvement in her cells symptoms. Speciﬁc antigen binding in response to B cell activa- causing this patient’s symptoms? She describes these lesions as tal complaining of hemoptysis and shortness of breath. The ulcers have She had been well until 3 months ago, when she noted been appearing for the last 6 months. For the last 2 days, vague symptoms of fatigue and a 10-lb unintentional the patient has had a painful red eye. Past medical history is notable only for osteo- ital ulcerations, arthritis, skin rashes, or photosensitivity. Her current symptoms began on the day of pre- On physical examination, the patient appears well devel- sentation with the expectoration of >200 mL of red blood oped and in no distress. Oxygen saturation is veals two shallow ulcers with a yellow base on the buccal 78% on room air and 88% on nonrebreather mask. The ophthalmologic examination is consistent is 120 beats/min, with a blood pressure of 170/110. The cardiopulmonary examination are diffuse crackles throughout both lung ﬁelds, and the is normal. She has no arthritis, but medially on the right cardiac examination is signiﬁcant only for a regular thigh there is a palpable cord in the saphenous vein. Labo- oratory studies reveal an erythrocyte sedimentation rate ratory studies reveal a hemoglobin of 10. The 3 ferential of 68% polymorphonuclear cells, 28% lympho- white blood cell count is 9760/mm. C3 is 89 mg/dL, and nalysis shows 1+ proteinuria, moderate hemoglobin, 25 C4 is 24 mg/dL. His medications include hydrochlorothiazide ing of left shoulder soreness that has been bothering him and acetaminophen as needed for pain. He experiences intermittent pain that is tion is remarkable for a moderate-size effusion of the right worse at night. Active abduction of his left arm over his knee, with range of motion limited to 90° of ﬂexion and head causes extreme pain. With weight that led to his pain but notes that he lifts weights and bearing, he has outward bowing of the legs bilaterally. On physical examination, radiogram of the right knee shows osteophytes and joint he has tenderness over the lateral aspect of the humeral space narrowing. Acromioclavicular arthritis complaining of recurring ulcers in the mouth and on his B. Inﬂammation of the infraspinatus tendon about 2 weeks before spontaneously resolving. Inﬂammation of the supraspinatus tendon tion, he intermittently gets skin lesions that he describes E. Although he complains of the ap- ing erythema after 72 h pearance of these lesions, they do not itch or hurt. Development of a 2- to 3-mm papule at the site of tient has not been previously evaluated for them and has insertion in 2–3 days recently noticed changes in the nail beds. Development of granulomatous inﬂammation 4–6 weeks, the patient has had increasingly severe pain in the weeks after the injection distal joints of the hands and feet. Development of an urticarial reaction within 15 min that he is having trouble writing and holding utensils. A 45-year-old African-American woman with sys- ness of breath, or changes in bowel or bladder habits. Which of the following is the most common clinical mmHg with a heart rate of 98 beats/min. A 60-year-old woman with a history of Sjögren’s propriate next step in the management of this patient? Initiate cyclophosphamide, 500 mg/m body surface care doctor complaining of facial swelling. She previously had cutaneous vasculitis requiring nisone, 1 mg/kg daily) and mycophenolate mofetil, 2 g treatment with prednisone, but she has been off steroids daily. Antihistone antibody swan-neck and boutonnière deformities in the hands as well C. Anti-Jo-1 antibody as plantar subluxation of the metatarsal heads that prevents D. He has been expe- except for right costovertebral angle tenderness and spleno- riencing knee pain for many months and has had no relief megaly. Laboratory studies at the time of presentation reveal from over-the-counter analgesics. He has a history of hy- 3 a white blood cell count of 2300/mm with 15% polymor- pertension and obesity. Which of the following represents phonuclear cells, 75% lymphocytes, 8% monocytes, and 2% the best initial treatment strategy for this patient? A 53-year-old woman presents to your clinic complain- mains anemic and neutropenic. The patient undergoes a ing of fatigue and generalized pain that have worsened over 2 bone marrow biopsy that shows hypercellularity with a lack years. Acute myelogenous leukemia separated from her husband and has been stressed at work.
Even though the uni- formity corrections at times can correct for large nonuniformities anafranil 10mg line, frequent retuning of the gamma camera is essential as these corrections affect lin- earity buy 50mg anafranil visa, resolution order 75 mg anafranil otc, and overall sensitivity of the camera buy cheap anafranil online. Gamma Camera Tuning 131 Edge Packing Edge packing is seen around the edge of an image as a bright ring and results in nonuniformity of the image. Normally a 5-cm wide lead ring is attached around the edge of the colli- mator to mask this effect. The source of radiation can be either the radi- ation from the patient or an external radioactive source, for example, 99mTc. Performance Parameters of Gamma Cameras Effects of High Counting Rates As discussed in Chapter 8, the scintillation cameras suffer count losses at high counting rates due to pulse pileup. Pulse pileup results from the detec- tion by the camera of two events simultaneously as one event with ampli- tude different from that of either original event. If one or both of the events are photopeaks, then the amplitude of the new event will be outside the pulse-height window setting and so the event will be rejected resulting in a loss of counts. If, however, two Compton scattered photons are processed together to produce an event equivalent to the photopeak in amplitude, then the event will be counted within the window setting. But the X, Y posi- tion of the event will be misplaced on the image somewhere between the locations of the two events. Both count rate loss and image distortion at high count rates must be taken into consider- ation in evaluating the performance of different cameras. Several techniques are employed to improve the high count rate performance of a gamma camera. In modern cameras, buffers (or deran- domizers) are used in which pulses are processed one at a time, and over- lapping events are kept on “hold” until the processing of the preceding event is completed. Other cameras use pulse pileup rejection circuits to minimize the count loss and image dis- tortion and thus to improve images, although they tend to increase the dead time of the camera. Recent developments include high-speed electronics that reduce the number of misplaced events and improve the image quality signiﬁcantly. Contrast Contrast of an image is the relative variations in count densities between adjacent areas in the image of an object. Contrast (C) gives a measure of detectability of an abnormality relative to normal tissue and is expressed as A − C = (10. Lesions on the image are seen as either “hot” or “cold” spots indicating increased or decreased uptakes of radioactivity in the corresponding areas in the object. Several factors affect the contrast of the image, namely, count density, scattered radiation, pulse pileup, size of the lesion, and patient motion, and each contributes to the contrast to a varying degree. Quality Control Tests for Gamma Cameras 133 Statistical variations of the count rates give rise to noise that increases with decreasing information density or count density (counts/cm2) and is given by (1/ N ) × 100, where N is the count density. For a given imaging setting, a minimum number of counts need to be collected for rea- sonable image contrast. Even with adequate spatial resolution from the imaging device, lack of sufﬁcient counts may give rise to poor contrast due to increased noise, so much so that lesions may be missed. This count density depends on the amount of activity administered and the uptake in the organ of interest. Contrast is improved with increasing administered activity and also with the differential uptake between the normal and abnormal tissues. However, due consideration should be given to the radiation dose to the patient from a large amount of administered activity. Sometimes, high count density is achieved by counting for a longer period of time in the case of low administered activity. It should be emphasized that spatial resolution is not affected by the increased count density from increased administered activity or longer counting. Background in the image increases with scattered radiations and thus degrades the image contrast. As discussed above, at high count rates, pulse pileup can degrade the image contrast. Image contrast to distinguish a lesion depends on its size relative to system resolution and its surrounding background. Unless a minimum size of a lesion larger than system resolution develops, contrast may not be suf- ﬁcient to appreciate the lesion, even at higher count density. The lesion size factor depends on the background activity surrounding it and on whether it is a “cold” or “hot” lesion. A relatively small-size “hot” lesion can be well contrasted against a lower background, whereas a small “cold” lesion may be missed against surrounding tissues of increased activities. This primar- ily results from the overlapping of normal and abnormal areas by the move- ment of the organ. It is somewhat alleviated by restraining the patients or by having them in a comfortable position. Quality Control Tests for Gamma Cameras To ensure high quality of images produced by imaging devices, several quality control tests must be performed routinely on gamma cameras. The frequency of tests is daily, weekly, and, for some tests, monthly or even quarterly. Performance Parameters of Gamma Cameras (peaking), uniformity, and spatial resolution of the camera. These tests can be carried out with the collimator attached to the camera (extrinsic) or without the collimator (intrinsic), and should be performed for each radionuclide used in a speciﬁc clinical study. In the intrinsic method, the source of a particular radionuclide contain- ing approximately 100 to 200mCi (3. Because the collimator is removed, the integrity of the collimator cannot be assessed by this method. In the extrinsic method, a sheet source is used made of plastic contain- 99m ing the radionuclide of interest. Because Tc is most commonly used in 99m nuclear medicine studies, a Tc sheet source is prepared by adding several millicuries of 99mTc activity to a water-ﬁlled plastic sheet container. Due to the inconvenience of daily preparation of the 99mTc sheet source and radiation exposure to the technologist during preparation, an alternative solid 57Co sheet source is used, which is commercially available in rectangular or 57 circular forms. Co has a longer half-life (~270d) and emits photons of 122keV and 136keV, which are equivalent to the 140keV photons of 99m 57 Tc. Because Co activity decays over time, counting time increases with time to accumulate sufﬁcient counts for the image. Peaking for 111In, 67Ga, 123I, 201Tl, and so on must be done separately, as needed. In modern cameras, peaking is performed automatically by menu-driven protocol-based software provided by the manufacturer. Initially at the time of the camera set-up, the photopeak window is set with a 99mTc source using the intrinsic method. Subsequently the daily check of the position of the photopeak is performed with a 57Co ﬂood source by the extrinsic method Quality Control Tests for Gamma Cameras 135 using a low-energy high-resolution collimator. Tuning is performed by the computer program by repeaking of the camera with a 99mTc source placed at least 30cm away from the detector and without a collimator (intrinsic method). Uniformity 57 The uniformity of the detector response is checked daily by using a Co ﬂood source. The ﬂood source is placed on the detector with a low-energy high-resolution collimator attached (extrinsic) and an energy window of 20% is used. C max − min integral uniformity = × 100 C max + min where Cmax and Cmin are the maximum and minimum count rates across the ﬁeld of view in a nine-point smoothed image. Images of a 57Co ﬂood source showing the uniformity (a) and nonunifor- mity (b) of the response of a gamma camera. Performance Parameters of Gamma Cameras high − low differential uniformity = × 100 high + low where “high” and “low” are the maximum and minimum differences in counts over ﬁve contiguous pixels in all rows and columns of the matrix. These values should be in the range of 1 to 2%, otherwise, the camera needs to be tuned. Weekly Checks Spatial Resolution and Linearity The spatial resolution and linearity of the gamma camera is checked weekly by using a bar phantom (Fig. An image is taken with approximately 10 million counts and visually inspected to check the linearity and separation of the smallest bars. Although extrinsic tests are done for convenience, intrinsic tests are prefer- able for better accuracy. Annual or As-Needed Checks Tuning of the camera is performed monthly or quarterly by the protocols described earlier. Other essential parameters such as energy resolution, high count rate response, multiwindow registration (e.
Primary surgical excision is the treatment of choice and should be performed regardless of tumor size as even small tumors can cause embolization or valvular obstruction purchase anafranil toronto. Surgical resection is generally curative with only a 1–2% recurrence rate in sporadic cases buy 75 mg anafranil free shipping. Tumors metastatic to the heart are more common than primary cardiac tumors and occur with the highest incidence in metastatic melanoma anafranil 75mg visa. However best anafranil 75mg, by absolute numbers of cases, breast and lung cancer account for the largest number of cases. Cardiac metastases usually occur in patients with known malig- nancies, are usually not the cause of presentation, and are found incidentally. Only 10% are clinically apparent at the time of presentation, and most are found at autopsy. A normal oxygen supply to the myocardium requires adequate inspired oxygen, intact lung func- tion (including diffusion capacity, which is abnormal in emphysema), normal hemoglo- bin concentration and function, and normal coronary blood ﬂow. The resistance to coronary blood ﬂow is determined by three vascular regions: large epicardial arteries, pre-arteriolar vessels, and arteriolar and intramyocardial capillaries. In the absence of signiﬁcant ﬂow-limiting atherosclerosis, the resistance in the epicardial arteries is negligi- ble. The major determinant of coronary-resistance is due to the pre-arteriolar, arteriolar, and intramyocardial capillary vessels. Although myocardial ischemia and subendocardial infarction can produce deep, symmetric T-wave inversions which would result in tachy- arrhythmias and syncope, noncardiac phenomena such as intracerebral hemorrhage can similarly affect ventricular repolarization. The average time to death after onset of symptoms is as follows: angina pectoris, 3 years; syncope, 3 years; dyspnea, 2 years; con- gestive heart failure, 1. In addition, surgery is advocated when the ejection frac- tion falls below 50% or when severe calciﬁcation, rapid progression, or expected delays in surgery are present. There is no speciﬁc age cut-off or degree of left-ventricular function that precludes surgical correction. This is, in part, due to the fact that there are no good medical therapies to treat aortic stenosis. Percutaneous balloon valvuloplasty has been used as a bridge to surgery and in patients with severe left-ventricular dysfunction or who are otherwise too ill to tolerate surgery. After birth, the ductus arteriosus closes as blood now circulates through the low-resistance pulmonary vascular bed. If the ductus arterio- sus fails to close after birth, a left-to-right shunt develops between the aorta and the pul- monary vasculature. Because the pressure in the aorta is greater than that of the pulmonary artery through all portions of the cardiac cycle, the murmur of a patent duc- tus arteriosus is a continuous murmur. There is late systolic accentuation of the murmur at the upper left sternal angle. The murmur is described as “machinery”-like, and often a palpable thrill is present. If Eisenmenger syndrome occurs, as in this patient, the shunt changes directional ﬂow and becomes a right-to-left shunt as a result of pulmonary hy- pertension. Because of the anatomic location of the ductus arteriosus below the level of the left subclavian artery, a characteristic of Eisenmenger syndrome in those with patent ductus arteriosus is cyanosis and clubbing of the toes but not the ﬁngers. Total anomalous pulmonary venous return occurs when all four pulmonary veins drain into the systemic venous circulation. This condition is fatal soon after birth if there is not also an atrial or ventricular septal defect or a patent fora- men ovale. Most patients with this condition are identiﬁed shortly after birth because of cyanosis. Coarctation of the aorta is a relatively common congenital abnormality that is associated with a stricture of the aorta near the insertion site of the ligamentum arterio- sus (the remnant of the ductus arteriosus). Upper extremity hypertension is present in association with low blood pressures in the lower extremities. Tetralogy of Fallot is a congenital heart disease syndrome with ventricular septal defect, right-ventricular outﬂow obstruction, aortic override of the ventricular septal defect, and right-ventricular hypertrophy. Ventricular septal defect results in left- to-right shunt and a holosystolic murmur rather than a continuous murmur. The musical quality of the murmur has been described when the cause is a ﬂail leaﬂet. These patients usually have hypoten- sion and rapidly develop pulmonary hypertension and signs of cardiogenic shock. Respiratory variation in mitral inﬂow velocity is an echocardiographic sign of tamponade physiology. High-frequency ﬂuttering of the ante- rior mitral leaﬂet is the characteristic echocardiographic ﬁnding of acute aortic regurgi- tation, seen most commonly in primary aortic valvular disease, aortic dissection, infective endocarditis, or chest trauma. These symptoms should raise the con- cern for aortic dissection as the cause of the chest pain, and prompt evaluation and treatment are essential to decrease mortality from this often fatal condition. Aortic dissections are classiﬁed by either the DeBakey or Stan- ford classiﬁcations. Type I is caused by an intimal tear in the ascending aorta and has propagated to include the descending aorta. The Stanford classiﬁcation has only two categories: type A, which involves the ascending aorta, and type B, which involves V. Risk factors for developing an aortic dissection include sys- temic hypertension (70%), Marfan syndrome, inﬂammatory aortitis, congenital valve abnormalities, coarctation of the aorta, and trauma. Aortic dissections are a medical emergency with a high in-hospital mortality due to aortic rupture, pericardial tampon- ade, or visceral ischemia. Because of the high associated mortality, it is imperative to evaluate and treat aggressively with early surgical intervention. Transesophageal echocardiography has 80% sensitivity for diagnosing ascending aortic dissections and will also provide infor- mation regarding valvular function and presence of pericardial tamponade. The decision regarding which test to perform should be based on the rapid availability of testing and clinical stability of the patient. Management of an aortic dissection initially begins with medical therapy to stabilize the patient and decrease blood pressure. This should be occurring concurrently with surgical consultation to plan deﬁnitive opera- tive repair on an emergent basis. Medical therapy should consist of antihypertensive therapy to rapidly reduce the systolic blood pressure to 100–120 mmHg. In addition, use of a beta blocker to reduce cardiac contractility and heart rate is recommended. Surgery involves excision of the intimal ﬂap, removal of the intramural hematoma, and placement of a graft. In some cases, replacement of the entire aortic root and aortic valve is necessary when the aortic valve is involved. With prompt surgical intervention, mortality from ascending aortic dis- section is ~15–25%. The differential diagnosis includes pulmonary vascular disease, restrictive cardiomyopathy, constrictive pericarditis, cor pulmonale, and any cause of longstanding left-sided heart failure. Iron stud- ies are a component of the evaluation for hemochromatosis, and fat pad biopsy is a component of the evaluation for amyloidosis, both of which may cause restrictive cardio- myopathy. The tuberculin test is useful for ascertaining the presence of prior infection with Mycobacterium tuberculosis, which is associated with the development of constric- tive pericarditis. A coronary angiogram would not be helpful in a young patient with no physical signs or echocardiographic ﬁndings of left-sided heart failure. Hypercalcemia, by shortening the duration of re- polarization, abbreviates the total time from depolarization through repolarization. In this scenario, the hypercalce- mia is due to the rhabdomyolysis and renal failure. These patients with type 2 diabetes and an abnormal lipid proﬁle have insulin resistance and a marked increase in cardiovascular risk. Elevated serum endothelin levels may contribute to hypertension, and elevated homocysteine levels have been suggested as a cardiovascular risk factor. Clinical Identiﬁcation of the Metabolic Syndrome—Any Three Risk Factors Risk Factor Deﬁning Level a Abdominal obesity b Men (waist circumference) >102 cm (>40 in. They should beneﬁt from life-style changes, similarly to men with categorical in- creases in waist circumference.