Roberto M. Lang

Assessment of right ventricular function using echocardiographic speckle tracking of the tricuspid annular motion: comparison with cardiac magnetic resonance.

Background: Assessment of right ventricular (RV) function is difficult due to the complex shape of this chamber. Tricuspid annular plane systolic excursion (TAPSE) measured with M‐mode echocardiography is frequently used as an index of RV function. However, its accuracy may be limited by ultrasound beam misalignment. We hypothesized that two‐dimensional (2D) speckle tracking echocardiography (STE) could provide more accurate estimates of RV function. Accordingly, STE was used to quantify tricuspid annular displacement (TAD), from which RV longitudinal shortening fraction (LSF) was calculated. These STE derived indices were compared side‐by‐side with M‐mode TAPSE measurements against cardiac magnetic resonance (CMR) derived RV ejection fraction (EF). Methods: Echocardiography (Philips iE33, four‐chamber view) and CMR (Siemens, 1.5 T) were performed on the same day in 63 patients with a wide range of RV EF (23–70% by CMR). TAPSE was measured using M‐mode echocardiography. TAD and RV LSF were obtained using STE analysis (QLAB CMQ, Philips). TAPSE, TAD and RV LSF values were compared with RV EF obtained from CMR short axis stacks. Results: STE analysis required <15 seconds and was able to track tricuspid annular motion in all patients as verified visually. Correlation between RV EF and TAD (0.61 free‐wall, 0.65 septal) was similar to that with M‐mode TAPSE (0.63). However, STE‐derived RV LSF showed a higher correlation with CMR EF (r = 0.78). Conclusion: RV LSF measurement by STE is fast and easy to obtain and provides more accurate evaluation of RV EF than the traditional M‐mode TAPSE technique, when compared to CMR reference.u2002(Echocardiography 2012;29:19‐24)

Echocardiographic Predictors of Pulmonary Embolism in Patients Referred for Helical CT

Background: Transthoracic echocardiography (TTE) is ordered frequently in patients with suspected pulmonary embolism (PE). Multiple indices have been suggested to play a useful diagnostic role. We sought to determine the relative predictive accuracy of suggested quantitative indices among patients referred for CT scanning for exclusion of PE. Methods: We retrospectively identified 67 consecutive patients who underwent CT for the exclusion of PE, and had a TTE within 48 hours of CT. Echo indices suggested to play a role in the diagnosis of PE were measured RV/LV area ratio, RV/LV end diastolic dimension ratio, the “McConnell” sign, interventricular septal shift (“D‐sign”), Pulmonary artery diameter, tricuspid regurgitation velocity, and “60/60 sign” (TR velocity < 3.9 m/sec plus pulmonary artery acceleration time < 60 msec). Results: CT confirmed PE in 41 (61%). Mean age was 58 (18–92). Forty‐five were female. Subjects with PE were younger, and more likely to be tachycardic and require ICU admission. Of the echocardiographic indices, RV/LV EDD ratio > 0.7 was the most accurate predictor (sensitivity 66%, specificity 77%). The McConnell sign was the most specific (96%), however, with poor sensitivity (16%). Mean TR velocities did not differ between those with and without PE (270 ± 74 vs. 294 ± 83, P = 0.25). Conclusions: RV/LV EDD ratio > 0.7 has good accuracy for the diagnosis of acute PE. RV/LV area ratio > 0.7 and McConnell sign are specific but not sensitive indicators of acute pulmonary embolism. The presence of these findings should prompt further diagnostic testing for PE.

Feasibility of measuring coronary flow velocity and reserve in the left anterior descending coronary artery by transthoracic Doppler echocardiography in a relatively obese American population.

Background: Transthoracic Doppler echocardiography (TTDE) assessment of coronary flow velocity reserve (CFVR) has been validated in Asian and European centers. This methodology has not gained acceptability in the United States due to the bias that coronary flow velocity (CFV) by TTDE might be difficult in an obese population with relatively poor acoustic windows. Methods: Baseline CFV in the left anterior descending coronary artery (LAD) by TTDE was obtained in 67 nonselected American patients. A subset of 38/67 received adenosine infusion for measuring CFVR of the LAD. Purpose: The aim of this study was twofold: (1) to determine the feasibility of measuring CFV and CFVR in the LAD by TTDE in a relatively obese American population, and (2) to compare CFV and CFVR values in this population with those previously obtained in a group of Japanese patients. Results: The mean body mass index (BMI) of the American population (28 ± 6 kg/m2, range: 18–46 kg/m2) was significantly higher than that of the Japanese group (23 ± 4 kg/m2, range: 15–37 kg/m2). Twenty‐five American patients were classified as obese (BMI >30kg/m2). Baseline CFV was obtained in 60/67 patients (feasibility: 90%) with a 10% need for intravenous contrast agent to enhance the delineation of the CFV envelope. The success rate in recording CFVR in American patients (92%) was nearly identical to that of a Japanese group (99%). The time‐averaged peak diastolic coronary flow velocity increased from 15.6 ± 5.5 cm/sec at baseline to 47.1 ± 17.9 cm/sec during adenosine infusion, and CFVR was calculated to be 3.22 ± 1.15 (range: 0.94–5.69). Intraobserver and interobserver variability for the CFV recording was 4.7 and 6.2%, respectively. Conclusions: These results suggest that the noninvasive measurement of CFV and CFVR of the LAD is feasible even in a relatively obese American population. Furthermore, the success rates for recording CFV and CFVR are similar to those measured in a Japanese population. This methodology has the potential to provide useful physiological information on the coronary circulation in American patients.

Use of Transesophageal Echocardiography for the Assessment of Traumatic Aortic Injuries.

Acute traumatic lesions of the thoracic aorta or its branches (TLA) constitute highly lethal yet treatable injuries that are increasingly diagnosed in surviving patients. Traumatic disruptions are limited to the region of the aortic isthmus in ∼ 90% of cases. Unlike aortography, usually referred as the gold standard diagnostic technique, transesophageal echocardiography (TEE) is a noninvasive imaging modality that can be rapidly performed at the patient bedside. Accordingly, TEE is being increasingly used as a first‐line screening test for the evaluation of patients with suspected TLA. The TEE signs associated with TLA depend on the anatomic type of aortic disruption. After a period of validation, multiplane TEE allows accurate diagnosis of traumatic disruptions of the aortic isthmus, with a sensitivity of 88% (range, 57%–100%) and a specificity of 96% (range, 84%–100%). False‐negative TEE results have been mainly attributed to lacerations of aortic branches. Accordingly, aortography must be routinely performed when a traumatic injury to brachiocephalic arteries is suspected. False‐positive TEE findings have been associated with the presence of ultrasound artifacts or atherosclerotic changes that mimic TLA. Accurate determination of the depth of aortic wall tears and diagnosis of blunt cardiac injuries during the TEE study are crucial to guide patient management. The presence of TEE signs associated with imminent risk of adventitial rupture should lead to prompt surgery. The use of TEE as a first‐line imaging modality simplifies the initial assessment of patients at high risk for TLA and helps guide acute management.

Evaluation of Myocardial Deformation in Patients with Sickle Cell Disease and Preserved Ejection Fraction Using Three-Dimensional Speckle Tracking Echocardiography

Background: Sickle cell disease (SCD) is a hemoglobinopathy that affects one in 500 African Americans. Although it is well established that patients with SCD have left ventricular (LV) diastolic dysfunction, it is not clear whether they have subtle LV systolic dysfunction despite preserved ejection fraction (EF). We used three‐dimensional speckle tracking echocardiography (3DSTE) to assess changes in both systolic and diastolic LV function in SCD. Methods: Transthoracic real time 3D images were obtained (Philips iE33) in 56 subjects, including 28 stable outpatients with SCD (age 33 ± 7 years) and 28 normal controls (age 35 ± 9 years). 3DSTE was performed using prototype software (4DLV Analysis, TomTec) to obtain LV volume and deformation time curves, from which indices of systolic and diastolic LV function were calculated. Results: In SCD patients, 3DSTE‐derived LV filling parameters were significantly different from normal controls, reflecting an increase in both rapid and atrial filling volumes and prolonged active relaxation, depicted by a decrease in filling volume fractions at fixed times and an increase in rapid filling duration. Global LV systolic function was not only preserved but increased compared to controls, as reflected by significantly increased global longitudinal strain. Importantly, twist angle and torsion as well as radial and circumferential components of 3D strain were similar in both groups. Conclusions: 3DSTE was able to confirm diastolic dysfunction, as expected in some patients with SCD. However, 3DSTE strain analysis did not reveal any changes in LV systolic function. These findings provide novel insight into the pathophysiology of the cardiovascular complications of SCD.

Multicenter Experience Using a New Prototype Transnasal Transesophageal Echocardiography Probe

Transesophageal echocardiography (TEE) is an invaluable diagnostic tool, particularly in patients with inadequate transthoracic echocardiographic examinations. In addition, continuous TEE has been used to monitor ventricular and valvular performance in the intensive care unit and the operating room. However, current generation transesophageal probes have limitations in the critical care setting due to their size. Recently, a prototype miniaturized transesophageal probe was developed to overcome these limitations. This probe was used by five medical centers for 194 examinations. A large proportion of these patients were in the intensive care unit (43%), as well as mechanically ventilated (39%). Seventy percent (70%) of the subjects in this study were intubated nasally with the prototype probe, with a success rate of 88.5%. Oral intubation was successful in every case. Subject tolerance was good, and 25% of the patients were intubated for > 1 h. Nasal intubation with the probe was more likely in intensive care patients, ventilated subjects, and patients who were intubated for > 1 hour. TEE with this miniaturized probe is feasible and safe even in multi‐instrumented critical care patients. This probe provides adequate diagnostic imaging capabilities and may allow imaging over prolonged periods of time, making it suitable for the serial monitoring of ventricular performance.

Improved detection of myocardial damage in sarcoidosis using longitudinal strain in patients with preserved left ventricular ejection fraction

Cardiac infiltration is an important cause of death in sarcoidosis. Transthoracic echocardiography (TTE) has limited sensitivity for the detection of cardiac sarcoidosis (CS). Late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) is used to diagnose CS but has limitations of cost and availability. We sought to determine whether TTE‐derived global longitudinal strain (GLS) may be used to identify individuals with CS, despite preserved left ventricular ejection fraction (LVEF), and whether abnormal GLS is associated with major cardiovascular events (MCE).

Right Heart Involvement in Patients with Sarcoidosis

The left ventricle (LV) is affected in 20–25% of patients with sarcoidosis and its involvement is associated with morbidity and mortality. However, effects of sarcoidosis on the right ventricle (RV) are not well documented. Our aims were to investigate the prevalence of RV dysfunction in patients with sarcoidosis and determine whether it is predominantly associated with direct cardiac involvement, severity of lung disease, or pulmonary hypertension (PH). We identified 50 patients with biopsy‐proven extra‐cardiac sarcoidosis and preserved LV function, who underwent echocardiography, pulmonary function (PF) testing, and cardiovascular magnetic resonance. RV function was quantified by free wall longitudinal strain. Tricuspid valve Doppler and estimated right atrial pressure were used to estimate systolic pulmonary artery pressure. Myocardial late gadolinium enhancement was considered diagnostic for cardiac sarcoidosis and assumed to involve both ventricles. Of the 50 patients, 28 (56%) had RV dysfunction, 4 with poorly defined PF status. Of the remaining 24 patients, 16 (67%) had lung disease, 8 (33%) had PH, and 10 (42%) had LV involvement. Ten patients had greater than one of these findings, and 4 had all 3. In contrast, in 4/24 patients (17%), RV dysfunction could not be explained by these mechanisms, despite severely reduced RV strain. In conclusion, RV dysfunction is common in patients with sarcoidosis and is usually associated with either direct LV involvement, lung disease, or PH, but may occur in the absence of these mechanisms, suggesting the possibility of isolated RV involvement and underscoring the need for imaging protocols that would include RV strain analysis.

Transnasal Transesophageal Stress Echocardiography

Exercise echocardiography is a widely used modality for the noninvasive assessment of coronary artery disease. However, limitations exist inherent to the acquisition of transthoracic echocardiographic images. Although transesophageal echocardiography has been used during pacing or pharmacological stress, its use during exercise stress testing has not been clinically feasible due to the large probe size. Recently, a miniaturized transesophageal probe was developed, and we sought to test the feasibility of using this probe during graded treadmill exercise testing. Normal subjects were studied with transnasal echocardiography during upright treadmill exercise testing. The transnasal probe was passed in 13 of the 15 subjects. Excellent‐quality monoplane two‐dimensional echocardiographic images were obtained in all patients in the upright position. During exercise treadmill testing, high quality clinically useful echocardiographic images of the left ventricular short axis could be maintained. We conclude that transnasal transesophageal stress echocardiography may offer a new modality for the exercise assessment of ischemic heart disease.

A physiological approach to drug therapy in dilated cardiomyopathy. Echo-Doppler evaluation of cardiac mechanics, myocardial energetics, and ventriculo-vascular coupling.

Cardiac ultrasound imaging can be used in conjunction with calibrated external pulse recordings to provide detailed information regarding cardiovascular hemodynamics. This review establishes a physiological framework for the echo‐Doppler assessment of cardiac mechanics, left ventricular energetics, and ventriculo‐systemic vascular coupling in patients with dilated cardiomyopathy. The section on cardiac mechanics concerns the evaluation of overall cardiac performance and its individual determinants. Particular emphasis is placed upon the use of noninvasive methodology to identify the relative contributions of altered loading conditions and intrinsic myocardial contractility to cardiac performance. The noninvasive evaluation of left ventricular energetics is based oh the physiological premise that myocardial oxygen consumption is a function of three major determinants, i.e., heart rate, contractility, and the integral of left ventricular systolic load (or wall stress). Following a brief discussion of the vascular properties that determine the relationship between pressure and flow in the systemic circulation, noninvasive methods for determination of systemic vascular resistance and arterial compliance are described. At the end of each section, practical clinical applications of these techniques to the evaluation and management of patients with dilated cardiomyopathy are presented. (ECHOCARDIOGRAPHY, Volume 8, March 1991)