Echocardiography (1)

Infective endocarditis

Infective endocarditis (IE) is a rare, life-threatening disease that has long-lasting effects even among patients who survive and are cured. IE disproportionately affects those with underlying structural heart disease and is increasingly associated with health care contact, particularly in patients who have intravascular prosthetic material. In the setting of bacteraemia with a pathogenic organism, an infected vegetation may form as the end result of complex interactions between invading microorganisms and the host immune system. Once established, IE can involve almost any organ system in the body. The diagnosis of IE may be difficult to establish and a strategy that combines clinical, microbiological and echocardiography results has been codified in the modified Duke criteria. In cases of blood culture-negative IE, the diagnosis may be especially challenging, and novel microbiological and imaging techniques have been developed to establish its presence. Once diagnosed, IE is best managed by a multidisciplinary team with expertise in infectious diseases, cardiology and cardiac surgery. Antibiotic prophylaxis for the prevention of IE remains controversial. Efforts to develop a vaccine that targets common bacterial causes of IE are ongoing, but have not yet yielded a commercially available product.

Reports on Confidential Enquiries into Maternal Deaths: management strategies based on trends in maternal cardiac deaths over 30 years

In the latest Report of the Confidential Enquiries into Maternal and Child Health (CEMACH; formerly Confidential Enquiries into Maternal Deaths (CEMD)), cardiac disease was the second commonest cause of maternal mortality. Currently there is much emphasis on appropriate referral and multidisciplinary planning for women with known cardiac disease. However, examining all maternal cardiac deaths in the CEMACH/CEMD reports over the last 30 years, to see whether the condition was known before pregnancy or developed during pregnancy, suggests that while reported maternal mortality due to cardiac disease overall has approximately doubled, the number due to known disease has changed little. Thus significant and increasing numbers of deaths occur in women without known disease, either in those with risk factors or in those who develop conditions in the absence of risk factors. Therefore, while there is a continuing need to counsel, refer and appropriately manage women with known pre-existing cardiac disease, attention must also be paid to screening women before pregnancy for evidence of cardiac disease or risk factors, and also to cardiac disease that develops de novo during pregnancy, since early screening and referral strategies alone will not prevent units from encountering such cases. All units therefore require processes for monitoring and managing women for the development of cardiac disease throughout their pregnancies.

Antithrombotic Therapy in Valvular Heart Disease—Native and Prosthetic

This chapter about antithrombotic therapy in native and prosthetic valvular heart disease is part of the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy: Evidence Based Guidelines. Grade 1 recommendations are strong and indicate that the benefits do, or do not, outweigh risks, burden, and costs. Grade 2 suggests that individual patients' values may lead to different choices (for a full understanding of the grading see Guyatt et al, CHEST 2004; 126:179S-187S). Among the key recommendations in this chapter are the following: For patients with rheumatic mitral valve disease and atrial fibrillation (AF), or a history of previous systemic embolism, we recommend long-term oral anticoagulant (OAC) therapy (target international normalized ratio [INR], 2.5; range, 2.0 to 3.0) [Grade 1C+]. For patients with rheumatic mitral valve disease with AF or a history of systemic embolism who suffer systemic embolism while receiving OACs at a therapeutic INR, we recommend adding aspirin, 75 to 100 mg/d (Grade 1C). For those patients unable to take aspirin, we recommend adding dipyridamole, 400 mg/d, or clopidogrel (Grade 1C). In people with mitral valve prolapse (MVP) without history of systemic embolism, unexplained transient ischemic attacks (TIAs), or AF, we recommended against any antithrombotic therapy (Grade 1C). In patients with MVP and documented but unexplained TIAs, we recommend long-term aspirin therapy, 50 to 162 mg/d (Grade 1A). For all patients with mechanical prosthetic heart valves, we recommend vitamin K antagonists (Grade 1C+). For patients with a St. Jude Medical (St. Paul, MN) bileaflet valve in the aortic position, we recommend a target INR of 2.5 (range, 2.0 to 3.0) [Grade 1A]. For patients with tilting disk valves and bileaflet mechanical valves in the mitral position, we recommend a target INR of 3.0 (range, 2.5 to 3.5) [Grade 1C+]. For patients with caged ball or caged disk valves, we suggest a target INR of 3.0 (range, 2.5 to 3.5) in combination with aspirin, 75 to 100 mg/d (Grade 2A). For patients with bioprosthetic valves, we recommend vitamin K antagonists with a target INR of 2.5 (range, 2.0 to 3.0) for the first 3 months after valve insertion in the mitral position (Grade 1C+) and in the aortic position (Grade 2C). For patients with bioprosthetic valves who are in sinus rhythm and do not have AF, we recommend long-term (> 3 months) therapy with aspirin, 75 to 100 mg/d (Grade 1C+).

Thrombolytics in infectious endocarditis associated myocardial infarction

The use of thrombolytics in the management of acute myocardial infarction in eligible patients is the accepted standard of practice. We present the case of an embolic myocardial infarction in the setting of acute infectious endocarditis, treated with thrombolytics, resulting in a massive intracerebral hemorrhage and the patient's death. Historical and current literature has shown a consistent and significant incidence of concurrent intracerebral mycotic aneurysms in the setting of infectious endocarditis. Despite this, a literature review of contraindications to the use of thrombolytics rarely recognizes endocarditis as a contraindication. It is imperative that the etiology for myocardial infarction be identified; if contraindications to thrombolytic treatment exist, alternative therapeutic interventions must be pursued. This case highlights the importance of the correct etiologic diagnosis of myocardial ischemia, and increases the awareness of the significant risks of intracerebral hemorrhage associated with the use of thrombolytics in the setting of endocarditis.

Case report: delayed resolution of severe pulmonary hypertension after isolated liver transplantation in a patient with cirrhosis

Pulmonary hypertension is now recognized to be a rare association of liver disease and portal hypertension. This report describes the slow resolution of symptomatic pulmonary hypertension in a 33-year-old woman with cirrhosis who underwent isolated liver transplantation. The patient survived the surgery and perioperative period without significant haemodynamic compromise. After liver transplantation, the patient was monitored with regular Doppler echocardiography. By 27 months the pulmonary hypertension had almost completely resolved. This observation is important, as it suggests that patients with severe pulmonary hypertension who survive the perioperative period may have an excellent outcome, although resolution may be slow.

Echocardiographic diagnosis of heart disease in Uganda

Five hundred consecutive cardiological patients were reviewed and evaluated by echocardiography in Mulago Hospital as a referral service. All diagnostic problems in cardiology in the hospital and to a certain degree from other institutions were reviewed. The commonest diagnosis was endomyocardial fibrosis (EMF) 19.8%, followed by congenital heart disease (CHD) 15% and rheumatic heart disease (RHD) 11%. The anatomical distribution of fibrotic lesions in EMF (left, right or biventricular) correlated with that found in previous autopsy series from Mulago Hospital thus demonstrating the accuracy of echocardiography. We were able to quantify the contribution of echocardiography to a correct diagnosis which varied between 13% in RHD to 90% in mitral valve prolapse (MVP). Echocardiography was able to confirm the clinical diagnosis of subacute bacterial endocarditis (SBE) in 69% of cases. The obtained data suggests that EMF may be the most common heart disease in Uganda contrary to the pattern of heart disease outlined in earlier works. The favourable cost/benefit ratio of echocardiography (i.e. its easy availability and maintenance), as well as the absence of consumable materials in comparison to other cardiac diagnostic tools such as catheterization, chest X-ray and ECG is emphasized, together with the multipurpose use of the machine.

Quantification of mitral regurgitant volume by the color Doppler proximal isovelocity surface area method: a clinical study

In vitro studies have demonstrated that regurgitant flow rate can be estimated by the color Doppler "proximal isovelocity surface area" (PISA) method. By applying the PISA method and continuity principle, we developed a formula to calculate mitral regurgitant volume: 2 pi r2.VN.FVI/Vo, where r = distance from the first jet alias to mitral leaflets, VN = aliasing velocity, FVI = flow velocity integral or regurgitant jet, and Vo = peak velocity through the regurgitant orifice. Doppler echocardiography was performed in 20 patients with mitral regurgitation. The mitral regurgitant volume was estimated by PISA and compared to cine ventriculographic grading. The results showed an increase in regurgitant volume by PISA compared with increasing angiographic grades of mitral regurgitation: 19 +/- 0.6, 18 +/- 5, 25 +/- 12, and 44 +/- 4 ml for grades 1+ to 4+, respectively (r = 0.77). Thus a formula developed from PISA is able to identify patients with a severe grade of mitral regurgitation and to provide an alternate approach to the noninvasive quantitation of mitral regurgitation.

Fatal intracerebral hemorrhage following thrombolytic therapy of embolic myocardial infarction in unsuspected infective endocarditis

Cerebral hemorrhage occurs in 0.2% of patients under the age of 60 years treated with thrombolytic therapy for acute myocardial infarction. A case of fatal cerebral hemorrhage following TPA therapy for myocardial infarction due to probable coronary artery embolism during unsuspected native valve infective endocarditis is reported.

COLOUR DOPPLER ECHOCARDIOGRAPHY IN THE MANAGEMENT OF CONGENITAL HEART DISEASE

Twenty patients with various forms of congenital heart disease admitted to Army Hospital Delhi Cantt were studied. After detailed clinical examination and routine investigations they were subjected to two dimensional and subsequently colour Doppler echocardiography. Two patients were operated on the data obtained by echocardiographi. studies only. Seven patients required preoperative catheterisation in addition to echographic examination. The operative procedures confirmed the lesions delineated on colour Doppler echocardiography. Three patients are on echocardiographic review and remaining seven are awaiting surgery to further confirm the diagnosis offered on colour Doppler echo. One pateint of complex lesion died before detailed evaluation could be carried out. Thus colour Doppler echocardiography, though considered highly accurate and non invasive investigation for assessment of congenital heart disease is still in the stage of infancy in paediatric set up and requires a high degree of expertise before it can replace preoperative catheterisation in majority of cases.

Enhancement of Doppler flow signals in the left heart chambers by intravenous injection of sonicated albumin

OBJECTIVES

The objective of this study was to evaluate the effect of a transpulmonary contrast agent on Doppler flow signals in the left heart chambers.

BACKGROUND

Echo contrast agents are good ultrasound reflectors and could be used as Doppler signal enhancers. Sonicated albumin microbubbles are transpulmonary echo contrast agents and could enhance left heart Doppler signals after peripheral venous injection.

METHODS

Thirty-one patients with various heart diseases without intracardiac shunts were assessed with Doppler echocardiography before and after injection of sonicated albumin.

RESULTS

After an intravenous injection, pulsed Doppler signals of transmitral flow became more intense in all 16 patients examined, although flow velocity itself was not changed. In Doppler color flow imaging, the maximal mitral regurgitant signal area increased from 312 +/- 405 mm2 to 434 +/- 465 mm2, an average increase of 59 +/- 40% in all 17 patients with mitral regurgitation (p < 0.01). These effects were considered to be due to improvement of signal to noise ratio by the enhancement of Doppler flow signals. The duration of enhancement of pulsed Doppler transmitral flow signals was significantly longer than that of the left ventricular echocardiographic opacification (44 +/- 11 s vs. 17 +/- 7 s, p < 0.01).

CONCLUSIONS

Intravenous injection of sonicated albumin can enhance the Doppler flow signals in the left heart chambers. This effect may be useful to improve the sensitivity of the Doppler system for detecting abnormalities of left heart blood flow such as mitral regurgitation.

Assignment of patients into the classification of cardiomyopathies

The original classifications of the cardiomyopathies based on anatomic criteria from radiographic and necropsy studies, as well as hemodynamic criteria from clinical and catheterization data, have been supplemented in recent years by information from noninvasive techniques. Echocardiography, radionuclide methods, and ambulatory ECG, in particular, have facilitated the ethical screening of family members and those less symptomatic than patients on whom the original classification was based. These powerful methods show a broad spectrum of anatomy and ventricular physiology along the natural history of and within the traditional categories of the cardiomyopathies. They also provide data on the effect of ventricular loading conditions affecting a range of diastolic filling patterns. This review has attempted to point out the areas of overlap among and/or controversy about the categories that have led us to a feeling of frustration when trying to neatly classify individual patients. The addition of filling patterns from Doppler echocardiography and nuclear angiography to the standard methods has been reviewed and hopefully will lend more perspective to the range of physiology seen in these conditions. The categories of cardiomyopathy should not be seen as excluding patients with the newly recognized variations in anatomy and ventricular filling patterns. Rather, the classification provides a framework on which to build and expand our understanding of these important conditions.

Syncope

In brief Syncopal episodes are usually benign, but some causes can be life-threatening. The differential diagnosis is extensive and includes vasovagal reaction, decreased intravascular volume, metabolic disorders, cardiac disorders, medication use and abuse, Valsalva maneuver, and intracranial conditions. A detailed account of the event and a medical history direct the workup. Combining a thorough physical examination that emphasizes the cardiovascular and neurologic systems with selective laboratory tests and noninvasive diagnostic studies may reveal why the patient lost consciousness during his or her athletic activities.

Should all patients with atrial fibrillation be screened with echocardiography?

OBJECTIVE

To address a patient care problem suggested by a quality assurance study: Should physicians of patients with atrial fibrillation who have not had echocardiography performed be encouraged to obtain echocardiograms in order to discover heretofore undetected mitral stenosis, which could be treated with anticoagulation, in order to avert strokes?

DESIGN

Decision analysis using a Markov-chain technique and quality-adjusted life expectancy.

SETTING

Outpatient clinics.

PATIENTS

Patients aged 40-80 years with chronic atrial fibrillation.

INTERVENTIONS

The following strategies were studied: 1) obtain echocardiograms for all patients and anticoagulate those with mitral stenosis; 2) anticoagulate patients with classic auscultatory sounds of mitral stenosis and obtain echocardiograms for patients with other murmurs; if an echocardiogram reveals mitral stenosis, anticoagulate; 3) anticoagulate all patients with murmurs; 4) anticoagulate all patients; 5) observe all patients (natural history).

MAIN RESULTS

The base analysis, using data available in the literature and on site, indicated that though performing echocardiography on all patients with atrial fibrillation gave the best quality-adjusted life expectancy, the differences among the five strategies studied were small. In addition, sensitivity analysis revealed that the decision was sensitive to many of the variables used in the analysis, especially the efficacy and the risks of anticoagulation.

CONCLUSION

A recommendation that cardiac ultrasonography be done for all patients with atrial fibrillation in order to detect clinically unrecognized mitral stenosis cannot be made.

Prevention and Management of Infective Endocarditis

Infective endocarditis is an infection of the endocardial surface of the heart and usually involves one or more heart valves but may occur on septal defects or the heart wall. Its incidence is approximately 1 per 1,000 adults and 0.5 per 1,000 pediatric hospital admissions. Factors predisposing to infective endocarditis include degenerative heart disease, survivable congenital cardiac defects, use of invasive procedures, chronic immunosuppression, and intravenous drug abuse. This article discusses the pathophysiology, diagnosis, therapy, and prevention of infective endocarditis.

Imaging of post-mortem coronary arteries by 30 MHz intravascular ultrasound

Intravascular ultrasound cross-sectional imaging of the atherosclerotic artery may be employed to guide plaque ablation by spark erosion, atherectomy, laser irradiation or other means. To assess whether in the coronary artery the echolucent zone of the three-layered ultrasound appearance of muscular arteries might be a reliable boundary to halt transluminal ablative angioplasty, epicardial coronary arteries were scanned under pressure over a distance of 4-8 cm at 1 mm intervals. A 5.2F catheter with a 30 MHz transducer rotating at 600 RPM was used. In 419 images from four post-mortem hearts, aged at death 22, 31, 56 and 82 years, the presence of a distinct echolucent zone was scored as percentage of the wall circumference. The median scores were 0%, 0%, 10% and 75%, respectively. In the three youngest hearts, the three-layered appearance was largely absent. In the 82 year old heart, in contrast, the three-layered appearance could generally be identified. Within subjects, the presence of an echolucent zone was variable in location. Qualitatively, neither abundant medial elastin tissue nor a reduced medial thickness could explain the absence of an echolucent zone when the ultrasound image was compared to the corresponding microscopic section. The results show that in the 82 year old heart, 30 MHz intravascular ultrasound discrimination of coronary wall layers would be adequate to guide transluminal plaque ablation. In the younger hearts, guided ablation would fail due to the limited presence of a distinct echolucent zone as an ultrasound landmark of the media. Whether the presence or absence of an echolucent zone is related to age remains to be determined.

The role of imaging in the management of cerebral and ocular ischaemia

The last decade has seen several major technological advances in vascular neuroradiology, the most clinically significant of which have been the facility to image the brain and the extracranial carotid bifurcation noninvasively with accuracy and safety. Another major advance has been unequivocal evidence from formal statistical overviews that antiplatelet therapy, particularly aspirin, reduces the risk of serious vascular events by about 25%. These advances have changed clinical practice such that most patients presenting with symptoms suggestive of cerebral ischaemia should now have cranial CT to exclude intracerebral hemorrhage, not only because the causes and prognosis of cerebral ischaemia differ from those of intracerebral hemorrhage, but because many patients with cerebral ischaemia should be considered for antiplatelet therapy. Besides the use of long term antiplatelet therapy and control of vascular risk factors, other acute treatment options are limited with the possible exception of anticoagulation, thrombolysis, cytoprotective agents and carotid endarterectomy. If, as seems likely, the current clinical trials show that carotid endarterectomy plus medical therapy improve upon the stroke-free survival of patients treated medically, at least in symptomatic patients with severe stenosis, the number of carotid endarterectomies performed will increase considerably because carotid bifurcation disease is the most common cause of cerebral and ocular ischemic events. It will then be even more important to be able to obtain accurate anatomical and physiological information about the extracranial and intracranial circulations with utmost safety. Duplex ultrasound is currently the noninvasive screening method of choice for carotid bifurcation disease because it is available, relatively cheap, and reasonably accurate. It not only images the vessel lumen and degree of stenosis, but also the morphology of the vessel wall and associated plaque, the relevance of which is still uncertain in the pathogenesis of cerebral and ocular ischaemia. A major limitation of duplex sonography is that it cannot reliably distinguish tight stenosis from occlusion and it does not image the proximal or distal carotid circulation. The aim of newer techniques will be to distinguish tight extracranial carotid stenosis from occlusion and to provide anatomical, physiological and pathological information about the intracranial circulation and ischemic lesions (in view of potential for thrombolytic therapy of major intracranial vessel occlusion) with safety and reproducible accuracy.