Glucose intolerance: the hidden danger in hypertensives!

Both systemic hypertension and abnormalities of glucose metabolism are independent recognised risk factors for the development of cardiovascular morbidity and mortality, but their effects become additive when they coexist. Hypertension and glucose intolerance increase arterial stiffness and lead to cardiac structural and functional changes such as left ventricular hypertrophy and diastolic dysfunction of the left ventricle. Oral glucose tolerance tests have shown that 58% of patients with systemic hypertension who have no cardiac history and who are not known to have diabetes, suffer from unrecognised abnormalities of glucose metabolism i.e. either diabetes or impaired glucose tolerance. Using the fasting plasma glucose level and/or glycated haemoglobin concentration to diagnose glucose intolerance in patients with systemic hypertension is insufficient because of their low sensitivity for the diagnosis of diabetes and their inability to identify impaired glucose tolerance. It is important to recognise abnormalities of glucose metabolism early in patients with systemic hypertension in order to implement appropriate management and avoid further complications. Failure to identify glucose intolerance results in serious underestimation of the cardiovascular risk of these patients and denies patients primary preventative measures, which are based on risk assessment. All patients referred to Hypertension Clinics for the management of raised blood pressure should therefore be investigated by glucose tolerance test.

Bridging the treatment gap: the secondary care perspective.

Protocols and integrated care pathways can be valuable in the hospital care of patients with heart failure or left ventricular systolic dysfunction after acute myocardial infarction. A designated member of staff, often a specialist nurse, must be responsible for identifying patients suitable for management by the protocol and for ensuring that the protocol is adhered to. A new training scheme for "limited echocardiography" might enable specialist nurses to investigate left ventricular function within the first 24 hours of admission. Patients should be discharged from hospital as soon as they are out of danger. At present, they are often kept in hospital for process reasons. A "continuing care" clinic run by a specialist nurse, where patients can be seen daily after discharge until they are stabilised, is one way of bridging the gap between secondary and primary care. Communication between secondary and primary care needs to improve and same day discharge summaries are essential.

Absent right precordial R waves are associated with reduced left ventricular function and poor prognosis in patients with aortic stenosis.

Right precordial Q waves can be present in patients with aortic stenosis as well as in those with anterior myocardial infarction. In order to evaluate the relationship of right precordial Q waves to left ventricular function and prognosis in patients with aortic stenosis, we studied 49 such patients with no history of myocardial infarction, by means of ECG, clinical history and echocardiography. 15 (31%) patients had Q waves in both V1 and V2 and 34 (69%) did not. There were no differences in age (77+/-9.0 years vs. 78+/-9.7), follow-up time (15+/-9.0 months vs. 18+/-10), gender (female:male 8:7 vs. 15:19), aortic valve gradient on Doppler (70.0+/-20 mmHg vs. 71+/-20) and left ventricular mass (360+/-118 g vs. 320+/-80) between the two groups (all P=NS). Left ventricular shortening fraction (22+/-9.0% vs. 28+/-8.5, P<0.05), ejection fraction (51+/-15% vs. 62+/-12, P<0.01) and circumferential fibre shortening (0.8+/-0.3 circ/s vs. 1.0+/-0.3, P<0.0s) were all significantly reduced in patients with right precordial Q waves compared to those without. During a mean follow-up of 1.5 years, 9 out of 15 (60%) patients with right precordial Q waves died compared with only 5 out of 34 (15%) patients with a normal QRS pattern died (P<0.01). In summary, a right precordial QS ECG pattern is present in nearly 1/3 patients with aortic stenosis and is associated with impaired left ventricular systolic function and adverse prognosis.

Elevated and sustained desire for sweet taste in african-americans: a potential factor in the development of obesity.

Oral habituation is a relatively long-lasting decrease in oral responsiveness that results from the repeated presentation of a single stimulus. The purpose of this study was to evaluate the degree of habituation to sweet-tasting foods and to determine whether there are differences in the rate of habituation between African Americans and European Americans. These two groups were compared because the prevalence of obesity and obesity-related disorders such as diabetes and hypertension is significantly higher among African Americans than among European Americans. Nine different commercial foods and beverages that differed in sweetness intensity and caloric density served as stimuli. Subjects tasted and rated each food once per minute for a 30-min period on scales related to desire for another taste of the same sample and desire for a different taste. The stimuli and portion size for each of the 30 samples were two candy bars (Ultra Slim-Fast Cocoa Almond Crunch Bar, 1/16 of a bar; Natural Nectar Peanut Butter Granola Bar, 1/16 of a bar), three beverages (Nestea Lemon Flavored Instant Tea with NutraSweet, 5 mL; Welch's Grape Juice, 5 mL; Pink Swimmingo Kool-Aid, 5 mL), two gelatin desserts (Cherry Flavored Jell-O Gelatin, 5 g; Cherry Flavored Jell-O Gelatin with NutraSweet, 5 g), one enteral nutrition drink (Vanilla Ensure Plus, 5 mL), and one pudding (Ultra Slim-Fast Chocolate Pudding, 5 g). Subjects consumed the entire portion of each sample. Habituation occurred for seven of the nine foods as judged by a decrease in the desire for another taste of the same food. The degree of habituation for European Americans and African Americans was similar except for the sweetest food (Cherry Flavored Jell-O Gelatin with NutraSweet), for which African Americans showed no habituation. The degree of habituation in both groups was unrelated to caloric density. Overall, young African Americans had a significantly greater desire for another taste of the same food than did young European Americans for seven of the nine foods, and this desire was strongly correlated with the sweetness intensity for young African Americans but not for young European Americans. Furthermore, young African Americans had a greater desire than young European Americans for a different taste for seven of nine foods. The greater desire for intense sweet tastes may be a factor in the elevated incidence of obesity and diabetes in African Americans. In addition, young African Americans had greater perceived stress in this study than did young European Americans. If African Americans use sweet taste to compensate for feelings of stress, this compensation may also contribute to weight gain.

Effects of age on aortic blood velocity at rest and during exercise in patients with coronary artery disease.

The effect of age on aortic blood velocity has been studied in 100 patients with angiographically-documented coronary artery disease, 500 of whom were receiving beta-adrenergic blocking agents. Using continuous-wave Doppler ultrasound, the aortic blood velocity signals, both at rest and at maximal-tolerated supine exercise, were obtained. From the Doppler signals the peak velocity (Vp), stroke distance (Sd; the velocity-time integral) and minute distance (Md = Sd x heart rate) were calculated. The measurements were repeated 6 weeks after coronary artery bypass grafting (CABG), performed in 30 patients. No relationship with age (p < 0.01) was found for any of the indices, either at rest or during exercise, except for the resting Md in patients not on beta-blockers, (p < 0.02). No difference in the slope of the relationship with age was found between patients on or not on beta-blockers, except for the resting Md (p < 0.02). Following CABG, a significant age relationship with Vp, Sd and Md was restored, during both resting and exercise, suggesting improvement of systolic left ventricular function following myocardial revascularization. In conclusion, the normal age relationships of the derivatives of aortic blood velocity Doppler ultrasound signals were not seen in patients with coronary artery disease, irrespective of whether they were on or off beta-blockers. The relationship changed following myocardial revascularization, suggesting their dependence on systolic left ventricular function.

Mitral valve prolapse and occult aortic coarctation.

A 22 year old man developed symptoms of left ventricular failure secondary to atrial fibrillation and congenital mitral regurgitation. After operation for mitral valve repair he was unable to be successfully weaned from cardiopulmonary bypass and this was ascribed to poor left ventricular function. He therefore underwent emergency cardiac transplantation but again was unable to be weaned from bypass. At post-mortem examination a previously undiagnosed aortic coarctation was revealed. The presentation of occult aortic coarctation is discussed, and its association with congenital mitral valve abnormalities reviewed.

Effect of activation sequence on ventricular refractoriness as determined by extrastimuli.

STUDY OBJECTIVE: The aim was to determine by the extrastimulus method the effect on the right and left ventricular effective refractory periods of moving the site of the pacing train away from the site of the extrastimulus. DESIGN: The ventricular effective refractory period was measured at the right and left ventricular apices using pacing trains at two heart rates, delivered to the ipsilateral ventricle, the contralateral ventricle, and the right atrium. SUBJECTS: Seven patients (six male), mean age 52 years (range 26-75 years), with either documented (six) or suspected (one) ventricular tachycardia were studied. Four had ischaemic heart disease and the remaining three had morphologically normal hearts. MEASUREMENTS AND MAIN RESULTS: The pacing train and extrastimulus delivered in the right ventricle produced the shortest effective refractory period at both heart rates: 220.8(SD 19) ms and 207.9(16) ms respectively. As the pacing train was moved to the right atrium, the effective refractory period lengthened to 246.4(22) ms and 219.3(20) ms at the two heart rates. There was further lengthening as the site of the pacing train was moved to the left ventricle, to 269.2(20) ms and 240.7(35) ms respectively. The same pattern was observed in the left ventricular effective refractory periods as the pacing train was moved from left ventricle to right ventricle and to right atrium. CONCLUSIONS: The ventricular effective refractory period lengthens as the site of the pacing train is moved away from the site of the extrastimulus. This may be explained by the effects of the distribution of the pacing energy within the myocardium and by intercellular electrotonic interactions. This has important clinical implications for the arrhythmogenic mechanisms of ventricular tachyarrhythmias.

Balloon dilatation of the aortic valve: limited success and early restenosis.

Balloon dilatation of the aortic valve was attempted 16 times in 15 patients with severe aortic stenosis. None died but one had a transient stroke after the procedure. At dilatation the gradient across the aortic valve was reduced by greater than 30% in 69% of patients and the Gorlin valve area (calculated in 7/15 patients) increased by 30% in half. But a comparison of Doppler gradients measured before and one to two days after dilatation in 11 patients showed a greater than 30% reduction in the simultaneously measured gradient in only four. Doppler gradient was the most accurate predictor of symptomatic benefit and a fall in Doppler gradient persisted mainly in patients whose peak to peak gradient fell by at least 40% at the time of the procedure. Balloon dilatation of the aortic valve is a relatively safe procedure but it is less successful than previous reports suggest, perhaps because of early restenosis. Some forms of aortic stenosis may be more amenable to this procedure than others.

Factors affecting the relationship between precordial electrocardiographic voltage and left ventricular wall thickness.

The relationship between left ventricular wall thickness and precordial electrocardiographic voltage was explored in thirty male subjects to determine the influence of two independent variables, precordial lead positions and skin thickness. The correlation coefficient of the relationship between SV2 + RV5 and mean left ventricular wall thickness was 0.41. When the precordial voltages were measured from two modified leads, one parasternal and one apical, whose positions were determined by locating the heart with ultrasound, the correlation coefficient was 0.57. Using multiple regression, a significant relationship was demonstrated between chest wall thickness and precordial voltage, and this relationship was explained by variations in skin thickness measured by calipers. The relationship between left ventricular wall thickness and precordial voltage is significantly influenced by skin thickness and lead placement.

Accurate detection of triple vessel disease in patients with exercise induced ST segment depression after infarction.

The severity of coronary artery disease is an important determinant of prognosis after acute myocardial infarction. The ability of a symptom limited exercise test to predict the presence of triple vessel disease was assessed in 221 patients three weeks after infarction. Coronary angiography was performed in patients with exercise induced ST segment depression. The presence of ST segment depression alone was poorly indicative of triple vessel disease; however, some specific features of ST segment changes on exercise were of predictive value. Downsloping ST segment configuration alone or horizontal ST segment depression associated with an early onset and a late recovery time after exercise correctly identified 30 (90%) of 33 patients with triple vessel disease whereas it incorrectly identified only 6 (15%) of 39 patients with single and double vessel disease. An abnormal blood pressure response was also predictive. In patients with ST segment depression after infarction triple vessel disease can be detected accurately by a combination of the electrocardiographic and haemodynamic variables attained on exercise.

Coincidence of true and false left ventricular aneurysms after myocardial infarction.

False aneurysm of the left ventricle is a rare complication of myocardial infarction. In this case cross sectional echocardiography demonstrated the presence of both true and false left ventricular aneurysms. This was confirmed at operation when both aneurysms were successfully resected.

Effect of intravenous and oral flecainide on ventricular tachycardia.

The effect of flecainide acetate, a class 1c antiarrhythmic agent, was examined in 15 patients with recurrent ventricular tachycardia. Intravenous flecainide was administered in a dose of 2 mg/kg at the time of intracardiac stimulation and recording studies. Oral flecainide was given to 10/15 patients and retesting was undertaken using an indwelling electrode. Intravenous flecainide terminated sustained stable tachycardia in 8/11 patients and prevented reinitiation of tachycardia in 5/10 patients. Oral therapy prevented induction of tachycardias in only 2/10 patients. Five patients had non-sustained tachycardia and three had slower sustained tachycardia. "New" non-clinical tachycardias could be induced in six patients after flecainide but five of these had had more than one type of induced tachycardia. Four of 10 patients remained free of tachycardias during follow-up. Withdrawal of oral treatment was necessary in three patients, one of whom had severe proarrhythmic effects. Two patients required additional antiarrhythmic therapy. Long-term suppression could not be predicted from the results of oral therapy, but testing after intravenous drug seemed to be a more useful prognostic indicator. In summary, intravenous flecainide is effective for slowing and termination of stable ventricular tachycardia. Oral therapy is also effective but caution should be exerted in patients with multimorphic tachycardias.

Comparison of electrocardiographic and echocardiographic measures of left ventricular hypertrophy in the assessment of aortic stenosis.

One hundred and nineteen patients with a clinical diagnosis of important aortic stenosis were assessed clinically and by electrocardiography and M mode echocardiography to determine the degree of left ventricular hypertrophy. Predicted left ventricular pressure was calculated from two previously described formulas. Comparisons were made between the various methods for assessing left ventricular hypertrophy to see which method most reliably predicted the severity of the stenosis as defined by invasive measurement of left ventricular pressure and peak aortic valve gradient. Direct measurement of left ventricular wall thickness from the echocardiogram, expressed as the mean of septal and posterior wall thickness, was the most accurate predictor (r = 0.75 for 29 patients with high quality echocardiograms), and surpassed derived indices (left ventricular mass (r = 0.68) and predicted left ventricular pressure derived from the two formulas (r = 0.39 and r = 0.68)) in adults. Echocardiographic results were significantly better than electrocardiographic, but only when the recordings were of very high quality. Average quality echocardiograms were no better than precordial electrocardiographic voltages for predicting the severity of aortic stenosis. The formulas for predicting left ventricular pressure were of more value in children than in adults, but they were still not sufficiently accurate to be predictive in individual cases. Electrocardiographic voltages were more accurate predictors of the severity of aortic stenosis in children than in adults.

Alcohol and dilated cardiomyopathy.

Alcohol has been considered a cardiotoxin for over a century, but the pathogenesis and natural history of alcohol-related heart disease remains obscure. The diagnosis still rests on the coincidence of alcoholism and a dilated hypocontractile heart in the absence of any other cause of dilated cardiomyopathy. Advances have been made in our understanding of the effects of acute and chronic alcohol administration both at a haemodynamic and cellular level, and recent studies have indicated that preclinical changes in LV dimensions and function are common in alcoholics. It is not known whether clinical cardiomyopathy, which develops in only 1-2% of heavy drinkers, occurs because of genetic predisposition, or the presence of synergistic cardiovascular risk factors. Abstinence remains the mainstay of treatment, but the prognosis is poor after development of frank heart failure.