Treatment of iatrogenic aortic dissection by percutaneous stent placement.

During elective cardiac catheterization via the right femoral artery, difficulty was encountered advancing the guidewire beyond the aortic arch and the procedure abandoned. The patient later developed back pain and hypotension. A contrast-enhanced spiral computed tomography scan confirmed aortic dissection, extending from an entry point in the external iliac artery to the arch. We hypothesized that the entry site was responsible for filling the dissection in the thoraco-abdominal component. A stent was placed in the iliac artery, occluding the entry point. This is the first report of aortic dissection, a rare complication of angiography, managed by percutaneous stenting of the entry point.

Prognostic value of stress echocardiography in women with high (> or = 80%) probability of coronary artery disease.

OBJECTIVE: To assess the prognostic significance of stress echocardiography in women with a high probability of coronary artery disease (CAD). SETTING: Secondary and tertiary cardiology unit at a university teaching hospital. PARTICIPANTS: A total of 135 women (mean (SD) age 63 (9) years) with pre-test probability of CAD > or = 80% were selected from a database of patients investigated by treadmill or dobutamine stress echocardiography between 1995 and 1998. MAIN OUTCOME MEASURES: Patients were followed up for occurrence of subsequent cardiac events (cardiac death, myocardial infarction, admission with unstable angina, and revascularisation) using a structured telephone interview and case note review. RESULTS: Each patient had between two and seven (mean 3.5) CAD risk factors and pre-test probability of CAD > or = 80%. Ninety three patients (68.9%) had negative stress echocardiography. Mean (SD) follow up was 20.1 (8.5) months. There were six events in the positive stress echocardiography group (two cardiac deaths, one unstable angina, three revascularisations), and one event in the negative stress echocardiography group. Cox regression analysis showed positive stress echocardiography (p = 0.02) and age (p = 0.03) to be the only univariate predictors and positive stress echocardiography to be the only independent predictor of future cardiac events (relative risk 8.9, confidence interval 1.0 to 76.5, p = 0.04). Cumulative event free survival to 38 months was 98% in the negative stress echocardiography and 50.7% in the positive stress echocardiography groups. CONCLUSION: In women with high pre-test likelihood of CAD: (1) negative stress echocardiography identifies a subgroup with low risk of cardiac events who do not require further invasive investigation and (2) positive stress echocardiography identifies a subgroup with increased risk of subsequent cardiac events.

Prognostic value of negative dobutamine stress echo in women with intermediate probability of coronary artery disease.

Women with an intermediate pretest probability of coronary artery disease represent a significant proportion of patients referred for the investigation of chest pain. Dobutamine stress echocardiography can be used to restratify these patients into a low-risk group without resorting to cardiac catheterization.

Computer-generated attenuation correction does not improve the accuracy of myocardial perfusion scintigraphy.

A short study was performed to determine if it is possible to increase the accuracy of thallium-201 (201T1) single photon emission tomographic myocardial perfusion imaging using computer-generated ('Chang') attenuation correction. The stress and rest myocardial perfusion studies from 22 patients with suspected or known ischaemic heart disease were reconstructed with and without "Chang' attenuation correction. For all patients, the scintigraphy results were compared with those of coronary angiography. Attenuation correction improved the accuracy of 201T1 myocardial perfusion imaging for defining myocardial ischaemia or infarction in 8% of coronary artery territories (23% of patients), but it was worse in 5% of coronary artery territories (14% of patients). These changes were not significant (McNemar's test). Therefore, computer-generated 'Chang' attenuation correction does not appear to improve the accuracy of myocardial perfusion scintigraphy. It is important that all techniques suggested to improve the accuracy of clinical images should be tested on patients before being widely used.

Anterior ST segment elevation due to isolated right ventricular infarction during right coronary angioplasty.

We describe the case of a 59-year-old man who developed anterior ST segment elevation and Q waves due to isolated right ventricular branch occlusion during right coronary angioplasty. Isolated right ventricular infarction was clearly demonstrated on echocardiography.

Reduction of mismatch of global ventilation and perfusion on exercise is related to exercise capacity in chronic heart failure.

BACKGROUND: The inability to match lung perfusion to ventilation because of a reduced cardiac output on exercise contributes to reduced exercise capacity in chronic heart failure. OBJECTIVE: To quantify ventilation to perfusion matching at rest and at peak exercise in patients with chronic heart failure and relate this to haemodynamic and ventilatory variables of exercise capacity. DESIGN: Eight men in New York Heart Association class II underwent maximal bicycle ergometry with expired gas analysis. MAIN OUTCOME MEASURES: On separate days, ventilation and perfusion gamma camera imaging was performed at rest, and at 80% of previous peak exercise heart rate during bicycle ergometry. The vertical distribution of mismatch between ventilation and perfusion (V/Q) was estimated from subtracted profiles of activity (ventilation and perfusion) to derive a numerical index of global mismatch. RESULTS: Maximal mean (SD) oxygen consumption on bicycle ergometry was 16.0 (4.5) ml min-1 kg-1. There was a reduction in the global V/Q mismatch index from 23.96 (5.90) to 14.88 (7.90) units (p < 0.01) at rest and at peak exercise. Global V/Q mismatch index at peak exercise correlated negatively with maximal minute ventilation (R = -0.90, p < 0.01) and with maximal mean arterial pressure (R = -0.79, p < 0.05), although no relation was seen with maximal oxygen consumption. The reduction in global V/Q mismatch index from rest to peak exercise correlated with maximal oxygen consumption (R = 0.88, p < 0.01), and with maximal minute ventilation (R = 0.87, p < 0.01). CONCLUSIONS: During exercise in patients with chronic heart failure, there is a reduction in the global V/Q mismatch index. A lower global V/Q mismatch index at peak exercise is associated with higher maximal ventilation. The reduction in global V/Q mismatch index on exercise correlates well with maximal exercise capacity. This may imply that the inability to perfuse adequately all regions of lung on exercise and match this to ventilation is a factor determining exercise capacity in chronic heart failure.

Inhaled bronchodilators increase maximum oxygen consumption in chronic left ventricular failure.

Bronchoconstriction is seen at rest in patients with chronic heart failure, and may contribute towards exercise limitation. To investigate the effect of bronchodilator agents on exercise capacity, 10 patients (mean age 60 years, range 39-72) in New York Heart Association class II and III heart failure, underwent symptom-limited maximal exercise testing after inhalation of nebulized salbutamol (5 mg), ipratropium bromide (500 micrograms) or placebo delivered on separate days in a randomized, double-blinded study. There was an increase in forced expiratory volume in one second from pre-treatment to after nebulizer, 2.28 +/- 0.20 to 2.38 +/- 0.19 l (P < 0.05) with salbutamol, and 2.27 +/- 0.21 to 2.37 +/- 0.21 l (P < 0.05) with ipratropium bromide. There was an increase in maximal oxygen consumption after salbutamol 17.9 +/- 1.3 ml.kg-1.min-1 (P < 0.05) and ipratropium bromide 17.0 +/- 1.4 ml.kg-1.min-1 (P < 0.05), compared with placebo 16.3 +/- 1.4 ml.kg-1.min +/- 1. Peak minute ventilation during exercise also increased after salbutamol 52.8 +/- 4.5 l.min-1 (P < 0.05), compared with placebo 46.1 +/- 3.1 l.min-1. The small but significant increase in exercise capacity in chronic heart failure following bronchodilator agents implies that a degree of bronchoconstriction is present in these patients and contributes to exercise limitation.

Short-stepping gait in severe heart failure.

BACKGROUND: Patients with severe chronic heart failure seem to take shorter steps than healthy controls when walking on a treadmill and when walking freely along a corridor. In healthy individuals the pattern of walking affects the oxygen cost of exercise, and so this observation might be relevant to the limitation of exercise in heart failure. METHOD: Length of stride was analysed as stride/stature index in 15 controls, 10 patients with moderate heart failure, 10 patients with severe heart failure, and 10 patients with angina, walking at a constant speed/stature index. RESULTS: The stride/stature index was 0.64 in the controls in patients with New York Heart Association (NYHA) class II heart failure, and in patients with angina. It was 0.49 in patients with NYHA class III heart failure. In the patients with heart failure the stride/stature index correlated with exercise capacity determined as peak oxygen consumption VO2max (R = +0.62, p < 0.005). When healthy controls walked in time to a metronome adjusted to decrease their stride/stature index to approximately that seen in severe heart failure steady-state oxygen consumption increased by a mean of 15%. CONCLUSIONS: The length of stride is reduced in severe heart failure, and when healthy controls adopt this gait the oxygen cost of walking is increased. A short-stepping gait may contribute to the limitation of exercise capacity in heart failure.

Reduced pulmonary microvascular permeability in severe chronic left heart failure.

Pulmonary edema is a serious complication of heart failure, but often patients with chronic heart failure resist pulmonary edema despite elevated pulmonary venous pressures. This protection might be a result of decreased pulmonary microvascular permeability. Double-isotope scintigraphy with 113mindium-labeled transferrin and 99mtechnetium-labeled erythrocytes allows noninvasive estimation of pulmonary microvascular permeability; an index of transferrin accumulation is calculated that reflects microvascular permeability. Fourteen patients with severe chronic left ventricular dysfunction were compared with a control group of 15 patients with mild coronary artery disease. In the control group the transferrin accumulation index was 0.35 (range -0.3 to 1.0) x 10(-3)/min, and in patients with heart failure the index was 0.0 (range -1.0 to 0.7) x 10(-3)/min, which was significantly lower (p less than 0.01). The reduction in the transferrin accumulation index correlated weakly with the duration of heart failure (R = -0.5, p less than 0.02). These data indicate reduced protein efflux consistent with a decrease in pulmonary microvascular permeability in patients with severe chronic heart failure. Similar changes have been observed in severe mitral stenosis and may reflect a generalized adaptation to chronic pulmonary venous hypertension.

Abnormal diastolic filling patterns in chronic heart failure--relationship to exercise capacity.

Abnormal patterns of diastolic ventricular filling are well recognized in chronic heart failure, but their relationship to the severity of heart failure is not known. The present study evaluates the relationship of diastolic filling indices to the severity of heart failure and to exercise capacity. In 40 patients with chronic heart failure secondary to ischaemic left ventricular impairment, exercise capacity was measured as peak oxygen consumption (VO2max) by progressive treadmill exercise. Left ventricular function was assessed by M-mode and Doppler echocardiographic indices. Peak aortic velocity correlated weakly with VO2max (R = +0.38, P less than 0.05). VO2max did not correlate with other systolic indices, including mean aortic acceleration, time to peak velocity, or isovolumic contraction time. VO2max correlated with the mitral inflow E/A ratio (R = -0.57, P less than 0.005) and with the Doppler estimate of isovolumic relaxation time (R = -0.48, P less than 0.01). Two distinct patterns of diastolic filling were observed: subjects with mild-to-moderate heart failure (NYHA grade II, VO2max 15-20 ml.kg-1.min-1) had abnormally low E/A ratios and long isovolumic relaxation times, whereas those with severe heart failure (NYHA grade III-IV, VO2max less than 12 ml.kg-1.min-1) had abnormally high E/A ratios and short isovolumic relaxation times. Different patterns of abnormal diastolic filling with different degrees of severity of heart failure may explain some of the previous controversy as to the prevalence of abnormal diastolic function in chronic heart failure. Exercise capacity in chronic heart failure appears more closely related to abnormalities of diastolic filling pattern than to indices of systolic function.

Use of limb movement sensors as indicators of the level of everyday physical activity in chronic congestive heart failure.

The level of everyday physical activity of patients with chronic congestive heart failure (CHF) may be an important reflection of their quality of life. Everyday physical activity is difficult to measure objectively, and may not relate to exercise capacity determined by laboratory exercise testing. A light-weight sensor worn on the wrist or ankle, which provides a cumulative record of limb movement, was evaluated. The sensor counted reliably when tested in a laboratory rig and during treadmill exercise. In 20 young normal subjects, hourly movement scores showed the expected diurnal rhythm. Twenty-four-hour movement scores in 30 patients with stable CHF were lower than in 20 age-matched control subjects (p less than 0.005). Movement scores in CHF correlated with a standard questionnaire scale assessing everyday physical activity (R = +0.72, p less than 0.001). Consecutive daily scores varied widely, but wrist and ankle scores were correlated (R greater than +0.7, p less than 0.05 in each subject), suggesting true day-to-day differences in activity rather than variability in the recording method. Recording for 5 to 6 consecutive days provides a reliable estimate of mean 24-hour movement score for a subject, and mean 24-hour scores were reproducible when subjects were retested after 8 weeks. There was a weak correlation between movement scores and exercise capacity as measured by peak oxygen consumption during maximal treadmill exercise (R = +0.42, p = 0.01). Quality-of-life score correlated with movement scores (R = +0.53, p less than 0.002) but not with peak oxygen consumption (R = +0.36; p = not significant).(ABSTRACT TRUNCATED AT 250 WORDS)

Exercise physiology and the role of the periphery in cardiac failure.

Cardiopulmonary exercise testing remains the standard method of functional assessment in chronic heart failure, and both peak oxygen consumption achieved on progressive maximal exercise testing and anaerobic threshold are widely used endpoints in clinical trials. Peak oxygen consumption achieved on progressive maximal exercise testing may be used in clinical practice to estimate prognosis and aid the prioritization of patients for cardiac transplantation. Anaerobic threshold is a valuable index of submaximal exercise performance, but there are many different criteria used to define anaerobic threshold and careful attention to the methodology is essential. The mechanisms of limitation of exercise capacity and the importance of the peripheral abnormalities in chronic heart failure are still not elucidated. The skeletal muscles are reduced in size, weak, and easily fatigued; in addition, nuclear magnetic resonance spectroscopic studies have shown that high-energy phosphates are depleted and acidosis develops more rapidly during exercise in patients with chronic heart failure than in normal subjects. However, the relationship of these abnormalities to the mechanical performance of the muscles, the differences between treated and untreated heart failure, and the effects of physical training have yet to be clarified.

Effects of amiodarone on erect and supine exercise haemodynamics and exercise capacity in patients with hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is a primary heart muscle disease associated with a high incidence of sudden death. Amiodarone is of benefit in those patients with a high risk profile for sudden death. Amiodarone has also been reported to improve symptoms dramatically in some patients with HCM but to cause functional deterioration in others. In the acute phase of oral amiodarone therapy there are few discernable changes in cardiovascular haemodynamics and the mechanisms of any beneficial effects on symptoms remain unclear. To determine the effect of amiodarone on exercise responses we measured haemodynamic indices in 10 patients during maximal supine- and symptom-limited erect treadmill exercise before and 6 weeks after amiodarone therapy. Following amiodarone therapy there was a significant reduction in resting and peak heart rate during erect exercise (76 +/- 13 vs 97 +/- 19 b.min-1; P = 0.001 and 114 +/- 26 vs 146 +/- 21 b.min-1; P = 0.001 respectively). Despite increases in peak pulmonary and systemic artery pressures with amiodarone therapy there was no difference in the peak left ventricular filling pressure or maximum cardiac output achieved. Similarly, during supine exercise the resting and peak heart rates were less following the 6 weeks amiodarone therapy. Comparison of supine and erect exercise haemodynamic indices demonstrated higher peak LV filling and higher peak systolic and pulmonary artery pressures during supine than during erect exercise (29 +/- 10 vs 25 +/- 12; P less than 0.04; 151 +/- 42 vs 126 +/- 48; P = 0.01 and 66 +/- 27 vs 62 +/- 21; P = 0.08 respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Pseudo preexcitation syndrome.

During the course of investigation for palpitations, a 62-year-old man underwent exercise testing using a MARQUETTE CASE 12 computerized exercise testing system. By stage III of the modified Bruce protocol, the computer-generated electrocardiogram appeared to show the development of exercise-induced preexcitation. Closer examination of the raw unfiltered data showed this to be a computer-generated artifact rather than true preexcitation. This artifact arose due to inherent limitations common to all computerized exercise testing systems and emphasizes the need to always review raw data, even when a seemingly clear-cut abnormality is present on a computer-averaged electrocardiogram.