Gerald I. Cohen

A practical guide to assessment of ventricular diastolic function using doppler echocardiography

Doppler assessment of diastolic function has become a standard part of routine echocardiographic examination and imparts information relevant to a patients functional class, management and prognosis. This review describes the Doppler patterns of diastolic function relative to physical signs and physiology. A continuum of doppler patterns of diastolic function exists, including normal diastolic function, impaired relaxation, pseudonormal filling, restriction, constriction and tamponade. These patterns evolve from one to another in a single individual, with changes in disease evolution, treatment and loading conditions. New applications of continuous wave Doppler, color Doppler M-mode and Doppler tissue imaging are refining our understanding of diastolic function.

Impact of electrical cardioversion for atrial fibrillation on left atrial appendage function and spontaneous echo contrast: Characterization by simultaneous transesophageal echocardiography

OBJECTIVES This study assessed the function of the left atrial appendage in the pericardioversion period to gain insights into mechanisms involved in thromboembolism after cardioversion of atrial fibrillation. BACKGROUND Systemic embolization associated with electrical cardioversion of atrial fibrillation is thought to originate from the left atrium or left atrial appendage, or both. However, the mechanism involved is poorly understood. METHODS We studied left atrial appendage function with transesophageal echocardiography in 20 patients with atrial fibrillation before and after successful electrical cardioversion. We measured left atrial appendage emptying and filling velocities by pulsed wave Doppler echocardiography, characterized Doppler emptying patterns, measured atrial appendage areas and assessed the presence or absence of spontaneous echo contrast or thrombus. RESULTS Organized left atrial appendage function returned in 16 (80%) of 20 patients immediately after cardioversion. Atrial appendage emptying velocities before cardioversion were greater in patients without (0.39 +/- 0.02 m/s) than in those with (0.25 +/- 0.12 m/s) spontaneous echo contrast (p = 0.045). Furthermore, emptying velocities before cardioversion were significantly greater than late diastolic emptying velocities after cardioversion (0.31 +/- 0.15 vs. 0.14 +/- 0.12 m/s, p = 0.0001), as well as in both the group with (0.25 +/- 0.12 vs. 0.13 +/- 0.13 m/s, p = 0.001) and the group without (0.39 +/- 0.02 vs. 0.15 +/- 0.12 m/s, p = 0.01) spontaneous echo contrast. In addition, left atrial and atrial appendage spontaneous echo contrast developed in 4 of 20 patients and increased in intensity in 3 of 20 patients in the immediate postcardioversion period. CONCLUSIONS Organized left atrial appendage function returns in most patients immediately after cardioversion of atrial fibrillation. However, its function is impaired compared with that before cardioversion. Furthermore, spontaneous echo contrast increased in 7 (35%) of 20 patients after cardioversion. These observations suggest that stunned left atrial appendage function after cardioversion may predispose the chamber to thrombus formation, which may play a role in the mechanism involved in the occurrence of embolization after cardioversion.

Cardiac tumors: Diagnosis and management

The first step towards the diagnosis of cardiac neoplasia is made when the clinician considers the diagnosis. While the classically described signs and symptoms of left-atrial myxomas are noteworthy, the vast majority of patients present with symptomatology that is less specific--either of a constitutional nature, or related to right- or left-sided congestion. Likewise, the physical examination may rarely disclose classic auscultatory signs, but is more likely to confirm the presence of the right- or left-sided congestion inferred from history. Peripheral, embolic, or vasculitis lesions should raise suspicion of the diagnosis. Nevertheless, the majority of patients will be diagnosed by the unexpected detection of a tumor at the time of echocardiography. Transthoracic echocardiography remains the procedure of choice in screening for cardiac neoplasia. It has excellent sensitivity for intracavitary and endocardial lesions. Myocardial lesions are also well imaged. Pericardial lesions, with or without extension into contiguous structures, are poorly visualized and, here, magnetic resonance imaging is unquestionably the superior investigative approach. Further, a limited degree of tissue characterization is possible with the latter technology. Transesophageal echocardiography is ideally suited for the examination of suspected tumors involving the atria, interatrial septum, superior vena cava, atrioventricular valves and, to a lesser extent, the ventricles. These three imaging modalities clearly complement one another and the choice of application will depend upon factors including the patients transthoracic echogenicity, the availability of magnetic resonance imaging or transesophageal echocardiography, cost, and the physical status of the patient.

Effects of mitral regurgitation on pulmonary venous flow and left atrial pressure: An intraoperative transesophageal echocardiographic study

OBJECTIVES AND BACKGROUND Pulmonary venous flows recorded by pulsed wave Doppler transesophageal echocardiography examination can be used to assess the severity of mitral regurgitation. Pulmonary venous flows are also related to left atrial pressures; however, the determinants of these flows have yet to be characterized in the presence of mitral regurgitation. METHODS We simultaneously recorded intraoperative pulmonary venous flows by transesophageal echocardiography and left atrial pressures by direct left atrial puncture in 16 patients with different grades of mitral regurgitation: 2+ (n = 5), 3+ (n = 4) and 4+ (n = 7). Pulmonary venous peak systolic and diastolic flow velocities and peak reversed systolic flow velocities were compared with left atrial pressure a and v waves, a-x and v-y descent values and left atrial volumes. RESULTS Pulmonary venous systolic to diastolic flow ratios correlated with decreases in left atrial pressure a/v ratios and with increases in the v waves of patients with higher grades of mitral regurgitation. Univariate analysis revealed that the best determinants of the pulmonary venous systolic to diastolic flow ratio were the left atrial pressure v wave (r = -0.76), the v-y descent value (r = -0.73) and the a/v ratio (r = 0.71). Lower correlations were found for left atrial end-systolic (r = -0.48) and end-diastolic (r = -0.42) volumes. Reversed systolic flow was present in patients with 4+ mitral regurgitation, despite left atrial enlargement. CONCLUSIONS Pulmonary venous flow can be used to assess the severity of mitral regurgitation and reflects the effects of mitral regurgitation severity on the left atrial pressure a and v waves.

Role of transesophageal echocardiography in the diagnosis and management of prosthetic valve thrombosis

Thrombosis is a serious complication of heart valve replacement. Diagnosis is often difficult with previously reported techniques, including precordial two-dimensional echocardiography, suffering from low sensitivity and specificity. Management is similarly difficult, with a 40% to 50% reported mortality rate in early surgical series. Three cases are presented in which thrombosis of a left-sided prosthetic valve (one aortic, three mitral) was diagnosed by means of transesophageal echocardiography. All three patients were treated with streptokinase and had clinical and echocardiographic resolution. In one patient, who had recurrent thrombosis and received a second course of streptokinase, the course was complicated by a massive embolic stroke and death. Another patient with a recurrence underwent successful valve replacement. Transesophageal echocardiography is ideal for the diagnosis and follow-up of patients with prosthetic valve thrombosis. Although effective, thrombolysis in this setting is associated with a high risk of thromboembolic phenomena and significant risk of death. Thrombolytic therapy may be considered in highly selected patients who have an unacceptable risk for reoperation.

Differentiation of constrictive pericarditis from restrictive cardiomyopathy by Doppler transesophageal echocardiographic measurements of respiratory variations in pulmonary venous flow

OBJECTIVES The purpose of this study was to test the utility of measuring respiratory variation in pulmonary venous flow by transesophageal echocardiography. BACKGROUND Respiratory variation of atrioventricular and central venous flow velocities by Doppler echocardiography has been used to differentiate constrictive pericarditis from restrictive cardiomyopathy. METHODS We performed pulsed wave Doppler transesophageal echocardiography of the left or right pulmonary veins in 31 patients with diastolic dysfunction. Fourteen patients had constrictive pericarditis, and 17 had restrictive cardiomyopathy. We measured the pulmonary venous peak systolic and diastolic flow velocities and the systolic/diastolic flow ratio with transesophageal echocardiography during expiration and inspiration. The percent change in Doppler flow velocity from expiration to inspiration (%E) was calculated. RESULTS Pulmonary venous peak systolic flow in both inspiration and expiration was greater in constrictive pericarditis than in restrictive cardiomyopathy. The %E for peak systolic flow tended to be higher in constrictive pericarditis (19% vs. 10%, p = 0.09). In contrast, pulmonary venous peak diastolic flow during inspiration was lower in constrictive pericarditis than in restrictive cardiomyopathy. The %E for peak diastolic flow was larger in constrictive pericarditis (29% vs. 16%, p = 0.008). The pulmonary venous systolic/diastolic flow ratio was greater in constrictive pericarditis in both inspiration and expiration. The combination of pulmonary venous systolic/diastolic flow ratio > or = 0.65 in inspiration and a %E for peak diastolic flow > or = 40% correctly classified 86% of patients with constrictive pericarditis. CONCLUSIONS The relatively larger pulmonary venous systolic/diastolic flow ratio and greater respiratory variation in pulmonary venous systolic, and especially diastolic, flow velocities by transesophageal echocardiography can be useful signs in distinguishing constrictive pericarditis from restrictive cardiomyopathy.

Complications of Transesophageal Echocardiography in Ambulatory Adult Patients: Analysis of 1500 Consecutive Examinations

Transesophageal echocardiography is a new approach that can be used to image cardiac structures. It combines two existing technologies: cardiac ultrasound and endoscopy. To obtain a cardiac image, the transesophageal probe has to be positioned properly within the esophagus. The first 1500 consecutive transesophageal echocardiographic examinations in ambulatory adult patients from one center were analyzed to identify conditions associated with failed esophageal intubation and procedural complications. Esophageal intubation was not achieved in 11 patients (0.73%). The reasons for the failure of intubation were operator inexperience, hypersensitive pharynx despite topical anesthesia, and cervical spondylosis. Six of those patients also had a history of dysphagia. Procedural complications were identified in seven patients (0.47%). Tracheal intubation was present in four patients, with immediate development of stridor and incessant cough in two patients. Atrial fibrillation developed in two patients--one had atrial myxoma and one had mitral stenosis. Bronchospasm developed during the transesophageal examination in one patient who was receiving long-term treatment for bronchial asthma. We conclude that transesophageal echocardiography is feasible in most adult patients in the ambulatory setting and that the complication rate is very low. Proper patient selection and preparation are crucial to the successful performance of this procedure.

Reference values for normal adult transesophageal echocardiographic measurements

Normal transesophageal echocardiographic measurements have not been presented previously relative to the effects of age, sex, and body surface area. This comparison was obtained by measuring cardiac and aortic dimensions in 60 patients (20 to 75 years old; 33 women) with normal transesophageal echocardiograms. We found a variable and usually important relationship between body surface area and 11 of 20 structures measured. A gender effect was not significant after indexing for body surface area for all but one structure. Age correlated with the diameter of the aortic root, descending aorta, superior vena cava, and right pulmonary artery. Similar dimensions were noted for certain paired structures as the two atria, the mitral and tricuspid annuli, and the aortic root and right ventricular outflow tract. Although multiple factors underlie what is normal in a given individual, our reference values serve to facilitate recognition of cardiac and aortic disease.

Technical aspects of diastology: why mitral inflow and tissue Doppler imaging are the preferred parameters?

Doppler methods for assessing left ventricular (LV) diastolic function have increased in number and complexity. However, time constraints may prevent measurement of all parameters during routine transthoracic echocardiography. Therefore, we designed a study to determine which Doppler parameters could be most successfully and quickly obtained. The recording success rate and time required to record different LV diastolic function parameters were evaluated in 80 patients. A specific recording protocol was followed by an experienced, credentialed sonographer and time intervals to record each parameter were measured. In comparison with color Doppler M‐mode of LV inflow propagation velocities (Vp) and pulmonary venous (PV) flow measurements, transmitral valve (MV) flow and tissue Doppler imaging (TDI) of the mitral annulus had the highest recording success rate and required the shortest time to record. PV flow and Vp took longer to obtain (80.1 ± 34.3 sec and 57.1 ± 29.1 sec, respectively) than did mitral valve inflow (36.3 ± 20.7sec) and mitral valve annular TDI (29.3 ± 18.4 sec for septal and 33.3 ± 14.5sec for lateral). MV flow velocities, Vp, and TDI were successfully recorded in virtually all patients (99–100%). In comparison, the PV flow velocities and durations were successfully recorded less often. The range of success rates for the six PV flow parameters was 49–84%. Since MV flow and TDI also have been shown by us to have the lowest interreader variability, measurement of these two parameters may be preferred for routine clinical evaluation of LV diastolic function in a busy echocardiography laboratory.

Importance of Sampling Both Pulmonary Veins in Grading Mitral Regurgitation by Transesophageal Echocardiography

Pulmonary venous flow patterns have been used to assess severity of mitral regurgitation; however, the issue of which pulmonary veins to sample has not been determined. We performed pulsed wave Doppler transesophageal echocardiography of both the left and right upper pulmonary veins in 80 patients who had mitral regurgitation determined by independent transesophageal echocardiography color flow mapping. Pulmonary venous flow patterns, peak systolic and diastolic flow, and the presence of reversed systolic flow were compared between the left and right pulmonary veins for each grade of mitral regurgitation. Flow patterns were discordant in 20 (25%) of the 80 patients. Of the 43 patients with 4+ mitral regurgitation, there was discordant flow in 16 (37%) of the patients with mainly reversed systolic flow in the right upper vein, while there was blunted or normal systolic flow in the left upper vein. Of the 16 patients with discordant flows, 14 had eccentric jets, mainly anteromedial jets. We conclude that if discordant flow can occur in 25% of patients with mitral regurgitation and in 37% of patients with 4+ mitral regurgitation, then both pulmonary veins must be evaluated when assessing the severity of mitral regurgitation with pulsed wave Doppler transesophageal echocardiography.