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Biomedical subjects

R Senior

Publications and source records attributed to R Senior.

At least 37 records · Page 2Linked to original sources
PubMed2002

Contrast echocardiography and acute coronary syndromes.

Since microvascular perfusion parallels myocardial viability, myocardial contrast echocardiography (MCE) can provide informations regarding myocardial recovery after an acute myocardial infarction (AMI). Recent studies have demonstrated the role of MCE to evaluate the value of perfusion and function during rest and dobutamine stress echo in patients early after AMI in terms of risk stratification and management of these patients.

Acute Disease↗
PubMed2002

Real time contrast echocardiography--a new bedside technique to predict contractile reserve early after acute myocardial infarction.

AIMS: Power pulse inversion echocardiography is a new technique by which contrast microbubbles can be visualised in real time within the myocardium, enabling simultaneous assessment of myocardial function and microvascular integrity, which is a prerequisite for myocardial viability. We aimed to determine whether microvascular integrity using power pulse inversion can be used to predict contractile reserve early after myocardial infarction. METHODS AND RESULTS: We studied 19 stable patients 5.1(1.6) days after presentation using low dose dobutamine stress echocardiography and power pulse inversion using slow bolus intravenous injections of Optison. A 16-segment left ventricular model was used to define wall thickening at baseline and following low dose dobutamine infusion (1, normal; 2, reduced; 3, absent), and contrast opacification (1, homogeneous; 2, heterogenous or reduced; 3, absent). The techniques were compared on a segment-by-segment basis to determine whether microvascular integrity (contrast opacification score of 1 or 2) could predict contractile reserve (any improvement during low dose dobutamine infusion) in segments that were akinetic at rest. Follow-up echocardiography was performed one month later. RESULTS: Ninety-four (31%) of the 304 segments were akinetic at rest, and 22 (23%) of these demonstrated contractile reserve. In 87 (92%) of the resting akinetic segments contrast opacification could be adequately determined, and of these 20 (23%) showed microvascular integrity. The negative and positive predictive value of microvascular integrity for determining contractile reserve was 90% and 65%, respectively, and 92% and 59% respectively for predicting recovery of function. CONCLUSION: Power pulse inversion can be used at rest to determine myocardial function and simultaneously to predict contractile reserve of akinetic segments in patients early after myocardial infarction. This technique has the potential to provide a bedside assessment of myocardial viability.

Aged↗
PubMed2001

Effect of revascularization on left ventricular remodeling in patients with heart failure from severe chronic ischemic left ventricular dysfunction.

Few data exist regarding the effect of revascularization on left ventricular (LV) geometry in patients with severe LV systolic dysfunction and viable myocardium. We hypothesized that patients with chronic ischemic LV dysfunction but viable myocardium will have improved LV geometry after revascularization, which in turn will improve long-term outcome. Accordingly, 70 patients with severe ischemic LV dysfunction (LV ejection fraction <0.35) were studied at rest. They then either underwent revascularization (n = 36) or were treated medically (n = 34). Fifty-four patients had viable myocardium, and 16 did not. They were evaluated for change in LV function and geometry (size and shape) a mean of 21 months later. Further follow-up was performed for a mean of 3.5 years to determine outcome. Patients with viable myocardium had improvement not only in regional and global function, but also in LV geometry (shape and size), which was independent of and incremental to the improvement in function. On long-term follow-up, change in LV end-systolic volume was the only multivariate discriminator between 15 patients who died and 55 who did not, irrespective of whether they had undergone revascularization. Thus, measurement of the effect of revascularization of viable myocardium in chronic ischemic heart disease should not only include improvement in resting regional and global LV function, but also LV geometry. Improvement in LV geometry contributes to better LV systolic function, which in turn is the best predictor of survival after revascularization.

Cohort Studies↗
PubMed2001

Effect of aging on the prognostic significance of ambulatory systolic, diastolic, and pulse pressure in essential hypertension.

BACKGROUND: This study compared the relative prognostic significance of 24 hour intra-arterial ambulatory systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), and pulse pressure (PP) parameters in middle-aged versus elderly hypertensives. METHODS AND RESULTS: A total of 546 subjects aged <60 years and 142 subjects aged >/=60 years who had undergone baseline pretreatment 24-hour intra-arterial ambulatory blood pressure monitoring were followed for 9.2+/-4.1 years. Multivariate analysis showed that in younger subjects, 24-hour, daytime, and nighttime DBP, MAP, and SBP, when considered individually, were positively related to morbid events; DBP parameters provided the best predictive values. In the group >/=60 years (elderly group), 24-hour, daytime, and nighttime PP and SBP were the most predictive parameters, whereas ambulatory DBP and MAP measurements failed to provide any prognostic value. When 24-hour values of SBP and DBP were jointly included in the baseline model, DBP (z=2.02, P=0.04) but not SBP (z=-0.43, P=0.67) was related to outcome in younger subjects, whereas in the elderly group, SBP (z=3.33, P=0.001) was positively and DBP (z=-1.75, P=0.07) was negatively related to outcome. Clinic blood pressure measurements failed to provide any independent prognostic value in either age group. CONCLUSIONS: The relative prognostic significance of ambulatory blood pressure components depends on age; DBP parameters provided the best prognostic value in middle-aged individuals, whereas PP parameters were the most predictive in the elderly. This may reflect differing underlying hemodynamic mechanisms of hypertension in these age groups.

Adult↗
PubMed2001

Intravenous myocardial contrast echocardiography predicts recovery of dysynergic myocardium early after acute myocardial infarction.

OBJECTIVES: We aimed to ascertain whether triggered intravenous myocardial contrast echocardiography (MCE) can predict functional recovery in patients with acute myocardial infarction (AMI) and to determine the optimal triggering interval in this setting. BACKGROUND: Detection of myocardial viability early after AMI has both therapeutic and prognostic implications. Myocardial contrast echocardiography using intracoronary injections of contrast can detect viable myocardium, but there is little data on the use of recently developed intravenous MCE techniques for this purpose. METHODS: Ninety-six patients with recent AMI (4.8 +/- 1.7 days) underwent echocardiography at baseline and six months later or three months after revascularization to determine regional function (score 1 = normal to 3 = akinetic). Myocardial contrast echocardiography was performed at baseline using intravenous injections of Optison. Triggering intervals of 1:1 (early) and 1:10 (delayed) cardiac cycles were used. Segments were deemed viable if they demonstrated homogeneous contrast opacification. RESULTS: Of 400 akinetic segments at baseline, 109 (27%) improved during the follow-up period, and 375 (94%) were adequately visualized with MCE, of which 59 (16%) were homogeneously opacified by early and 125 (33%) by delayed MCE (negative predictive value for recovery of contractile function 74% and 84%, positive predictive value 29% and 47%, respectively). Independent predictors of functional recovery were delayed MCE (odds ratio [OR]: 4.0, p < 0.001), revascularization (OR: 6.0, p < 0.001), and log creatine kinase (OR: 0.5, p = 0.03). However, the presence or absence of >90% stenosis of the infarct-related artery did not influence the ability of triggered MCE to predict functional recovery. CONCLUSIONS: Intravenous delayed triggered MCE can independently detect myocardial viability early after AMI.

Aged↗
PubMed2001

Regression of left ventricular remodeling in chronic heart failure: Comparative and combined effects of captopril and carvedilol.

BACKGROUND: This study evaluated the independent and combined effects of captopril and carvedilol on left ventricular remodeling in chronic heart failure. Although angiotensin-converting enzyme inhibitors and b-blockers are known to attenuate the remodeling process in chronic heart failure, a direct comparison of these agents has not been performed. METHODS: We investigated 57 patients with mild to moderate chronic heart failure (48 ischemic, 9 nonischemic) who were randomized in a double-blind fashion to treatment with carvedilol or captopril at maximum doses of 25 mg twice daily for 3 months, followed by 3 months of combined treatment. Serial echocardiography, right heart catheterization, and treadmill exercise testing were performed at baseline, 3 months, and 6 months. After exclusions, 49 patients were evaluated during monotherapy and 48 during combination therapy. RESULTS: Carvedilol monotherapy produced significant reductions in end-systolic volume, leading to a greater median increase in ejection fraction compared with captopril monotherapy (4.7% vs 1.5%, respectively; P <.05). Each drug caused similar reductions in left ventricular mass, chamber sphericity, and pulmonary artery wedge pressure during monotherapy and combined treatment. Adjunctive treatment with carvedilol produced a trend toward a greater increase in ejection fraction (4.3% vs 2.7%, respectively; P not significant) and significantly greater reductions in the wall thickening score index than with captopril (0.25 vs 0.08, respectively; P =.04). CONCLUSIONS: Although angiotensin-converting enzyme inhibitor therapy did not alter left ventricular volume, treatment with carvedilol was associated with reductions in chamber volume; both drugs reduced left ventricular mass and sphericity. These beneficial effects on remodeling may help to explain the relative prognostic benefits of these therapies.

Adrenergic beta-Antagonists↗
PubMed2001

Role of dobutamine echocardiography in detection of myocardial viability for predicting outcome after revascularization in ischemic cardiomyopathy.

Coronary artery disease is the most common cause of heart failure in the Western world. Compared with medical therapy, surgical revascularization has been shown to improve survival rates in nonrandomized trials in patients with ischemic cardiomyopathy. However, perioperative mortality is high in this group of patients who do not demonstrate significant viable myocardium. Echocardiography during dobutamine infusion has been shown to reliably detect viable myocardium. Several studies have demonstrated its ability to provide high predictive value for recovery of both regional and global left ventricular function after revascularization. Indeed, nonrandomized studies also have indicated its value in predicting which patients with severe ischemic cardiomyopathy are likely to survive after revascularization. Dobutamine stress echocardiography has emerged as a safe and valuable technique for the assessment of myocardial viability and for the selection of patients for revascularization.

Cardiotonic Agents↗
PubMed2001

Apical hypertrophic cardiomyopathy: bedside diagnosis by intravenous contrast echocardiography.

Apical cardiomyopathy is rare in the West. The characteristic appearance on left ventriculography has been used to confirm the diagnosis of this condition; transthoracic echocardiography can also be useful in this regard. However, apical artifacts may obscure the typical appearance during echocardiography, and although the advent of tissue harmonic echocardiography has resulted in improved image quality, the technique still may be inadequate in the establishment of a diagnosis. We hypothesized that contrast echocardiography, which improves endocardial border delineation, may be the technique of choice for the diagnosis of apical hypertrophic cardiomyopathy. We report the case of a 40-year-old woman with Down syndrome who had chest pain. The electrocardiogram showed T-wave changes in the lateral precordial leads, but cardiac enzymes were normal. Tissue harmonic echocardiography showed apical akinesia. Intravenous contrast echocardiography, however, revealed typical features of hypertrophic apical cardiomyopathy. Thus contrast echocardiography may be used to establish the diagnosis of this condition.

Adult↗
PubMed2001

Papillary fibroelastoma of the left atrial appendage.

Cardiac papillary fibroelastomas are benign tumors that usually arise from the valvular endocardium. They are clinically important because of their propensity to embolize. We describe, to the best of our knowledge, the first reported case of a papillary fibroelastoma arising from the left atrial appendage, giving rise to multiple cerebral embolic events. The tumor was excised surgically, with no further embolic events.

Atrial Appendage↗
PubMed2001

A prospective comparison of echocardiographic wall motion score index and radionuclide ejection fraction in predicting outcome following acute myocardial infarction.

OBJECTIVE: To characterise echocardiographic wall motion score index (WMSI) as a surrogate measure of left ventricular ejection fraction (EF) following acute myocardial infarction (AMI) and to compare its prognostic value with that of EF measured by radionuclide ventriculography (RNV). DESIGN: A prospective study to compare baseline echocardiographic WMSI with RNV EF in consecutive patients thrombolysed for AMI, both performed on the same day before discharge, and their relative prognostic values in predicting cardiac events. SETTING: District general hospital coronary care unit and cardiology department. PATIENTS: 120 consecutive patients free of exclusion criteria thrombolysed for AMI and followed up for a mean (SD) of 13 (10) months. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Correlation coefficients and receiver operating characteristic curve analyses plus cardiac event rates at follow up between RNV EF and echocardiographic WMSI. RESULTS: WMSI correlated well with RNV EF. The best corresponding WMSIs for EFs 45%, 40%, and 35% were 0.6, 0.8, and 1.1, respectively. There were 42 cardiac events during follow up. Although both RNV EF and WMSI were strong univariate predictors of cardiac events, only WMSI independently predicted outcome in a multivariate model. All three WMSI cut offs significantly predicted events, while an RNV EF cut off of </= 45% v > 45% failed to reach significance. CONCLUSIONS: Although both RNV and echocardiographic WMSI strongly predicted cardiac outcome, WMSI, a cheaper and more readily available technique, is more discriminatory, especially in cases of mild left ventricular dysfunction following AMI.

Adult↗
PubMed2000

Power doppler harmonic imaging: a feasibility study of a new technique for the assessment of myocardial perfusion.

BACKGROUND: The aim of the study was to assess the feasibility of a new technique, power Doppler harmonic imaging (PDHI), for assessing myocardial perfusion through a venous injection of microbubbles, with the use of a new ultrasound contrast agent. METHODS AND RESULTS: Fifteen patients with known coronary artery disease and a resting perfusion abnormality on Tc-99m sestamibi single-photon emission computed tomography (SPECT) underwent PDHI at rest during intravenous injections of 2 to 3 mL of Sonovue (Bracco SpA, Milan, Italy), a new second-generation ultrasound contrast agent. Myocardial perfusion was determined to be present or absent by use of a 5-segment model by 2 blinded observers for both PDHI and SPECT. Of a total of 75 possible myocardial segments, 7 (9%) were not analyzed because of obvious artifacts on PDHI. SPECT showed perfusion defects in 40 of the remaining 68 segments, whereas PDHI showed 39 defects. There was high concordance between the 2 imaging modalities for the presence (93%) as well as the location (96% for the anteroseptal region, 93% for the inferoposterior region, and 87% for the apical region) of the defects. CONCLUSIONS: These preliminary results suggest that PDHI is a feasible technique for the detection of resting myocardial perfusion defects in patients with coronary artery disease after a venous injection of a new second-generation ultrasound contrast agent.

Adult↗
PubMed2000

Enhanced left ventricular endocardial border delineation with an intravenous injection of SonoVue, a new echocardiographic contrast agent: A European multicenter study.

The safety and efficacy of SonoVue (also referred to as BR1), a new contrast agent for delineating endocardial border of the left ventricle after intravenous administration, was assessed. Two hundred and eighteen patients with suspected coronary artery disease undergoing fundamental echocardiography for the assessment of left ventricle were enrolled in a prospective multicenter, single blind, cross-over study with random sequence allocation of four different doses of SonoVue. Endocardial border definition in the apical and parasternal views was scored as 0 = not visible, 1 = barely visible, and 2 = well visualized before and after contrast enhancement. Analysis was performed by two pairs of off-site observers. Safety of SonoVue was also assessed. Results of our study indicated that the mean improvements in the endocardial border visualization score were as follows: 3.1 +/- 7.8 (95% CI, 2.5 and 3.7) for 0.5 ml, 3.4 +/- 8.0 (95% CI, 2.8 and 4.0) for 1 ml, 3.4 +/- 7.9 (95% CI, 2.8 and 4.0) for 2 ml, and 3.7 +/- 8.0 (95% CI, 3.1 and 4.3) for 4 ml (P < 0.05 for all doses from baseline). Changes from baseline in endocardial visualization scores were also seen in the apical views (P < 0.05) and they were dose-dependent (P < 0.001). Similar enhancements of endocardial visualization scores were observed in the apical views in patients with suboptimal baseline echocardiographic images. Diagnostic confidence for assigning a score and image quality also were significantly better following contrast enhancement. No significant changes in the laboratory parameters and vital signs were noted following contrast enhancement, and the side effects were minimal. It was concluded that SonoVue is safe and effective in delineating endocardial border, including in patients with suboptimal baseline images.

Aged↗
PubMed2000

Racial variation in cardiovascular morbidity and mortality in essential hypertension.

OBJECTIVES: To perform a longitudinal comparison of morbidity and mortality among white, south Asian and Afro-Caribbean hypertensive patients in relation to baseline demographic characteristics and clinic and ambulatory blood pressure variables. DESIGN: Observational follow up study. SETTING: District general hospital and community setting in Harrow, England. PATIENTS: 528 white, 106 south Asian, and 54 Afro-Caribbean subjects with essential hypertension who had undergone 24 hour ambulatory intra-arterial blood pressure monitoring. INTERVENTIONS: Follow up for assessment of all cause morbidity and mortality over a mean (SD) of 9.2 (4.1) years. MAIN OUTCOME MEASURES: Non-cardiovascular death, coronary death, cerebrovascular death, peripheral vascular death, non-fatal myocardial infarction, non-fatal stroke, coronary revascularisation. RESULTS: South Asians had the highest all cause event rate of 3.46, compared with 2.50 (NS) and 0.90 (p = 0.002) events/100 patient-years for whites and Afro-Caribbeans, respectively. This was because of an excess of coronary events (2.86 v 1.32 events/100 patient-years in south Asians v whites, respectively; p = 0.002). Age (p < 0.001), sex (p < 0.001), race (south Asians : whites, hazard ratio 1.79; p = 0.008), diabetes (p = 0.05), previous history of cardiovascular disease (p < 0.001), and 24 hour ambulatory systolic blood pressure (p = 0.006) were independent predictors of time to a first event. Clinic blood pressure did not provide additional prognostic information. CONCLUSIONS: South Asian origin was an independent predictor of all cause events, mainly because of an excess of coronary events in this group. Ambulatory but not clinic blood pressure was of additional value in predicting subsequent morbidity and mortality.

Adult↗
PubMed1999

Prediction of coronary and cerebrovascular morbidity and mortality by direct continuous ambulatory blood pressure monitoring in essential hypertension.

BACKGROUND: The goal of this study was to assess the prognostic value of ambulatory versus clinic blood pressure measurement and to relate cardiovascular risk to ambulatory systolic and diastolic blood pressure levels. METHODS AND RESULTS: The study population consisted of 688 patients 51+/-11 years of age who had undergone pretreatment 24-hour intra-arterial ambulatory blood pressure monitoring on the basis of elevated clinic blood pressure. A total of 157 first events were recorded during a 9.2+/-4.1-year follow-up period. The predictive value of a regression model containing age, sex, race, body mass index, smoking, diabetes mellitus, fasting cholesterol level, and previous history of cardiovascular disease was significantly improved by the addition of any ambulatory systolic or diastolic blood pressure parameter (whether 24-hour, daytime, or nighttime mean) or pulse pressure, whereas inclusion of baseline clinic blood pressure variables did not enhance the prediction of events. The most predictive models contained the ambulatory systolic blood pressure parameters. In the model containing 24-hour mean ambulatory systolic blood pressure (P=0.001), age (P<0.001), male sex (P<0.001), South Asian origin (P=0.008), diabetes mellitus (P=0. 05), and previous cardiovascular disease (P<0.001) were additional independent predictors of events. Whereas 24-hour ambulatory systolic blood pressure was linearly related to the incidence of both coronary and cerebrovascular events, 24-hour ambulatory diastolic blood pressure exhibited a positive linear relationship with cerebrovascular events but a curvilinear relationship with coronary events. CONCLUSIONS: Ambulatory blood pressure is superior to clinic measurement for the assessment of cardiovascular risk; there is no reduction in coronary risk at lower levels of ambulatory diastolic blood pressure.

Adult↗