L. Michael Prisant

Magnetic resonance imaging compared to echocardiography to assess left ventricular mass in the hypertensive patient.

Echocardiography (ECHO) is useful to document changes in left ventricular mass (LVM) in groups of patients, but may be too variable for use in the individual patient. Magnetic resonance imaging (MRI) may be a more precise and reliable method to quantify the mass of the left ventricule. This study reports the accuracy, precision, and reliability of LVM estimates by MRI as compared to data obtained by ECHO in hypertensive patients. Accuracy referred to the comparison of LVM by MRI to anatomical LVM determined by autopsy. Precision was examined using 34 duplicate MRI images and by blindly reading 24 duplicate M-mode strips. Reliability was assessed by MRI in four subjects over 2 months, and by ECHO in 22 hypertensive patients over 2 weeks. Agreement between MRI and ECHO estimates of LVM was determined in the same 17 hypertensive patients using linear regression. MRI LVM estimates were within 17.5 g (95% CI) of the true LVM. The linear agreement between MRI and ECHO estimates of LVM could be described by the equation MRI = 0.61 x ECHO + 49.57 (r = 0.63, P < .01). The precision of LVM by MRI (11 g) was over twice that observed with ECHO (26 g). The reliability of MRI LVM estimates was more consistent (+/- 8 g) than that for ECHO (+/- 49 g). MRI appears to be a more precise and reliable method for measuring LVM, and would be more suitable than ECHO for the clinical evaluation of the individual patient.

Relation among impaired coronary flow reserve, left ventricular hypertrophy and thallium perfusion defects in hypertensive patients without obstructive coronary artery disease

Abstract Invasive Doppler catheter-derived coronary flow reserve, echocardiographic measurements of left ventricular hypertrophy and intravenous dipyridamole-limited stress thallum-201 scintigraphy were compared in 48 patients (40 were hypertensive or diabetic) with clinical ischemic heart disease and no or coronary artery disease. Abnormal vasodilator reserve (ratio The decrement in flow reserve was not linearly related to the of left ventricular hypertrophy. Abnormal vasodilator reserve subsets found in hypertensive patients were defined on the basis of basal flow velocity, indexed left ventricular mass and clinical factors. In this series, diabetes did not cause a detetable additional decrement in flow reserve above that found with hypertension alone. These findings demonstrate that thallium perfusion defects are associated with depressed coronary vasodilator reserve in hypertensive patients without obstructive coronary artery disease, Left ventricular hypertrophy by indexed mass criteria is predictive of which hypertensive patients are likely to have thallium defects. Depressed coronary reserve is typically found in hypestensive patients with hypertrophy and increased basal coronary flow velocity, but less typical presentations including hypertrophy and normal or low coronary low velocity are found in advanced hypertensive disease.

The human sexuality education of physicians in North American medical schools

Individuals seeking treatment for sexual problems frequently would like to turn to a source they consider knowledgeable and worthy of respect, their doctor. The objective was to assess how well the 125 schools of medicine in the United States and the 16 in Canada prepare physicians to diagnose and treat sexual problems. A prospective cohort study was carried out. The main outcome results were description of the medical educational experiences, teaching time, specific subject areas, clinical programs, clerkships, continuing education programs in the domain of human sexuality in North American medical schools. The results were as follows. There were 101 survey responses (71.6%) of a potential of 141 medical schools (74% of United States and 50% of Canadian medical schools). A total of 84 respondents (83.2%) for sexuality education used a lecture format. A single discipline was responsible for this teaching in 32 (31.7%) schools, but a multidisciplinary team was responsible in 64 (63.4%) schools (five schools failed to respond to the question). The majority (54.1%) of the schools provided 3–10 h of education. Causes of sexual dysfunction (94.1%), its treatment (85.2%) altered sexual identification (79.2%) and issues of sexuality in illness or disability (69.3%) were included in the curriculum of 96 respondents. Only 43 (42.6%) schools offered clinical programs, which included a focus on treating patients with sexual problems and dysfunctions, and 56 (55.5%) provided the students in their clerkships with supervision in dealing with sexual issues. In conclusion, expansion of human sexuality education in medical schools may be necessary to meet the public demand of an informed health provider.

Low-dose drug combination therapy: An alternative first-line approach to hypertension treatment

To investigate the concept that the initial treatment of hypertension with low doses of two antihypertensives that have different modes of action and additive effects may achieve control of blood pressure and minimize the dose-dependent adverse effects seen with conventional monotherapy, a randomized, double-blind parallel group dose-escalation study was conducted. After a 4 to 5 week placebo washout period, 218 men and women with diastolic blood pressure between 95 and 114 mm Hg were randomly allocated to take: amlodipine (2.5 to 10 mg), enalapril (5 to 20 mg), and the low-dose combination of bisoprolol (2.5 to 10 mg) with 6.25 mg of hydrochlorothiazide (HCTZ). All drugs were administered once daily, titrated to optimal response, and taken for a total of 12 weeks. Blood pressure was measured 24 hours after dose. The response rates (either a diastolic blood pressure < or = 90 mm Hg or a decrease of diastolic pressure > or = 10 mm Hg) were 71% for bisoprolol-6.25 mg HCTZ, 69% for amlodipine, and 45% for enalapril. The mean decreases in systolic/diastolic blood pressure from baseline were 13.4/10.7, 12.8/10.2, and 7.3/6.6 mm Hg for bisoprolol-6.25 mg HCTZ, amlodipine, and enalapril, respectively. The mean change with enalapril was less than the other drugs (p < 0.01), although the once-daily dosing of enalapril and the maximum dose of 20 mg might not have been optimal for this agent.(ABSTRACT TRUNCATED AT 250 WORDS)

Measurement of left ventricular mass in hypertrophic cardiomyopathy using MRI : comparison with echocardiography

Left ventricular mass (LVM) is an important consideration in the management of cardiac hypertrophy associated with hypertrophic cardiomyopathy (HCM), systemic hypertension, and other diseases. A brief MRI cardiac imaging procedure used to monitor regression of LVM during treatment would be beneficial in management of these patients, since echocardiograms cannot be obtained in all patients and since the volume of a hypertrophic heart can straightforwardly be assessed from a series of tomographic slices. The present study was designed to evaluate a brief cardiac MRI procedure for measurement of LVM in HCM and compare it to echocardiography. MRI images acquired in a simulated transverse body plane were used to evaluate the mass of the left ventricle in 6 ex vivo human hearts obtained at autopsy. The estimates of LVM by MRI in the ex-vivo hearts were within 8% of the actual LVM. MRI images were acquired to evaluate LVM in 5 normal subjects and 12 patients diagnosed with HCM. Echocardiography was accomplished on 4 of the normal subjects and 10 of the patients having HCM. There were no significant differences in LVM by MRI and echocardiographic techniques in normal subjects. Transverse MRI images acquired on normal subjects demonstrated that estimates of LVM are reproducible when repeated over 3-w to 3-mo intervals. Images selected for analysis represented the heart in an early diastolic phase. MRI and echocardiographic techniques demonstrated significant differences in LVM in HCM patients. Estimates of LVM in normal subjects and patients diagnosed with HCM were normalized for body weight. The LVM estimates for HCM patients were very significantly different than normal subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Hyperthyroidism: A Secondary Cause of Isolated Systolic Hypertension

Isolated systolic hypertension is the most common form of hypertension, especially among patients 50 years or older. What is not appreciated is that there are secondary causes of isolated systolic hypertension. Hyperthyroidism increases systolic blood pressure by decreasing systemic vascular resistance, increasing heart rate, and raising cardiac output. Potential cardiovascular consequences of hyperthyroidism include atrial arrhythmias (especially atrial fibrillation), pulmonary hypertension, left ventricular hypertrophy, and heart failure. The prevalence of hypertension is greater among hyperthyroid patients than euthyroid patients. Whether there is a blunted nocturnal decline in ambulatory blood pressure among hyperthyroid patients is more controversial. Treatment is associated with a reduction in systolic blood pressure, heart rate, and cardiac output.

Preventing Type II Diabetes Mellitus

Burgeoning obesity is increasing the prevalence of type II diabetes mellitus. As a consequence, there will be an even greater burden of cardiovascular disease, end‐stage renal disease, blindness, and lower extremity amputations. If diagnosed, impaired glucose tolerance presents an opportunity for intervention that potentially could delay or prevent the development of diabetes. Recent prospective studies document the effectiveness of exercise and weight reduction in preventing diabetes. Metformin is less effective than intense lifestyle interventions. Acarbose, losartan, orlistat, pravastatin, ramipril, and hormone replacement therapy are associated with lower rates of the development of diabetes. The Diabetes Reduction Assessment with Ramipril and Rosiglitazone Medication (DREAM) trial and the Nateglinide and Valsartan in Impaired Glucose Tolerance Outcomes Research (NAVIGATOR) trial were designed to assess not only the prevention of diabetes but also the impact on cardiovascular morbidity and mortality.

Significance of positive or negative thallium-201 scintigraphy in hypertrophic cardiomyopathy

Myocardial ischemia, fibrosis and infarction may occur in patients with hypertrophic cardiomyopathy (HC) in the absence of epicardial coronary artery disease. To determine their prevalence and relation with common characteristics, stress thallium-201 scintigraphy was performed in 28 patients. Eleven (39%) had positive scans despite normal epicardial coronary arteries (7 patients) or a pretest risk of coronary disease less than or equal to 5% (4 patients). There was no relation between thallium defects and age, sex, chest pain or outflow tract gradients at rest. However, the mean left ventricular ejection fraction was significantly lower in those with perfusion abnormalities compared with those without (64 +/- 15 vs 75 +/- 11%, respectively, p less than 0.05). Also, the mean ventricular septal thickness was greater in patients with positive scans (27 +/- 7 vs 21 +/- 6 mm, p less than 0.05), and there was a nonparametric relation between increasing septal thickness and the frequency of positive scans (p less than 0.025). Seven of 11 patients with positive scans had ventricular tachycardia compared with none among those who had negative scans (p less than 0.001), and 5 of these 11 patients had conduction system disease requiring permanent pacemaker insertion compared with 1 of 17 with negative scans (p less than 0.025). It is concluded that thallium perfusion abnormalities are common in patients with HC in the absence of epicardial coronary disease, and are strongly associated with potentially lethal arrhythmias. Thallium scintigraphy appears to identify a subset of patients with HC at increased risk for sudden death, who therefore require closer follow-up.

Losartan: First of a New Class of Angiotensin Antagonists for the Management of Hypertension

Angiotensin receptor antagonists represent a new class of drugs for the treatment of patients with hypertension. Reduction of blood pressure in patients with essential hypertension requires increased activity of the renin—angiotensin system. Losartan, the first orally active, nonpeptide angiotensin antagonist, specifically competes with angiotensin II (Ang II) for the AT1 receptor and reversibly alters the receptor. Maximum blood pressure reductions occur after doses of approximately 50 mg, although some patients will require 100 mg; the parent compound and a metabolite are responsible for a smooth 24‐hour effect on blood pressure. Once‐daily dosing with losartan has been documented to be safe. The drugs safety has been evaluated in 4,058 patients; of these patients, more than 1,200 were treated for longer than 6 months and more than 800 were treated for longer than 1 year with doses of 10 mg to 150 mg. Overall, no hypertensive patients were withdrawn from treatment because of elevated serum creatinine or potassium levels, and there were no reports of angioedema. In addition, some reductions in plasma uric acid levels were noted. Cough occurred significantly less often in patients treated with losartan than in those treated with hydrochlorothiazide or lisinopril. In contrast to angiotensin‐converting enzyme (ACE) inhibitors, losartan does not activate bradykinin—nitric oxide—prostanoid vasodilation.

Idiopathic thrombocytopenic purpura in the older adult patient.

Forty adults with idiopathic thrombocytopenic purpura (ITP), aged over 45 years, were seen from March 1954 to December 1983 at the Medical College of Georgia. All patients had bleeding manifestations at presentation. Twenty-one of 40 (52.5%) during the follow-up period had either life-threatening or fatal bleeding episodes. There were no significant differences for the presence of any presenting clinical or laboratory feature for patients who achieved a complete remission compared with those who did not. A complete response to therapy, younger age, higher presenting hemoglobin level, and absence of central nervous system bleeding favorably influenced overall survival. Therapy was ineffective in this age group, with only 12 patients (30%) achieving a permanent complete remission. Fourteen patients (35%) died either from bleeding or from direct complications of therapy. This analysis of ITP in the older adult suggests a disease refractory to therapy that is associated with major morbidity and mortality.