Natesa G. Pandian

Three-dimensional and four-dimensional transesophageal echocardiographic imaging of the heart and aorta in humans using a computed tomographic imaging probe.

We evaluated the clinical applicability of a prototype tomographic transesophageal echocardiographic (TEE) system, which not only provides conventional TEE images but also three‐dimensional tissue reconstruction and four‐dimensional display capabilities. The probe was used in 16 patients in the echocardiographic laboratory, intensive care unit, and the operating room. The instrument is a 5‐MHz, 64‐element, phased array unit mounted on a sliding carriage within a casing. After appropriate probe placement within the esophagus, the probe is straightened, a balloon surrounding the probe is inflated, and data acquisition begun with ECG and respiration gating. With computer controlled transducer movement at 1‐mm increments, a complete cardiac cycle is recorded at each tomographic level. These are processed using a dedicated four‐dimensional software, and displayed as a dynamic three‐dimensional tissue image of the heart. We were able to see the dynamic motion of the ventricles and all the valves in the four‐dimensional format. In addition to four‐dimensional display, we were able to cut and visualize the heart in dynamic mode in any desired plane and also in multiple planes. Patients tolerated the procedure well. We conclude that this tomographic four‐dimensional approach, which does not require tedious off‐line processing, can easily be performed in patients and has a strong clinical potential.

Multiplane transesophageal echocardiography

Multiplane transesophageal echocardiography is a new exciting development in echocardiography. We examined the methodology and echo‐anatomic correlations of multiplane transesophageal echocardiography and its clinical applications in 100 patients. We used a 5‐MHz phased array multiplane (OmniPlane) transesophageal probe. In this instrument, the transducer array can be steered through 180° from any transducer location. This provides a vast assembly of imaging planes, allowing for detailed visualization of all dimensions of cardiac anatomy. This report presents our observations on the echocardiographic anatomy seen in various image planes and the unique clinical potential of multiplane transesophageal echocardiography in the diagnostic assessment of cardiovascular disorders. This technique appears to provide incremental diagnostic information that enhances the interpretative ability. Less esophageal probe manipulation is required with consequent decrease in patient discomfort. We conclude that multiplane transesophageal echocardiography enhances the versatility of transesophageal examination and offers many new avenues for developments such as three‐dimensional echocardiography.

Dynamic Three-Dimensional Echocardiographic Imaging of Congenital Heart Defects in Infants and Children by Computer-Controlled Tomographic Parallel Slicing Using a Single Integrated Ultrasound Instrument

Three‐dimensional cardiac reconstruction generated from transesophageal interrogation can be performed using an integrated unit that captures, processes, and postprocesses tomographic parallel slices of the heart. This probe was used for infants and young children in the transthoracic position to evaluate the feasibility of producing three‐dimensional cardiac images with capability for realtime dynamic display. Twenty‐two infants and children (range 1 day–3.5 years) underwent image acquisition using a 16 mm 5 MHz 64 element probe placed over the precordium. Two infants were also imaged from the subcostal position. Data was obtained and stored over a single cardiac cycle after acceptable cardiac and respiratory gating intervals were met. The transducer was advanced in 0.5–1 mm increments over the cardiac structures using identical acquisition criteria. The images were reconstructed from the stored digital cubic format and could be oriented in any desired plane. In 9 of the 22 infants the images obtained were of optimal quality. The images obtained displayed normal cardiac structures emphasizing depth relationships as well as visualization of planes not generally demonstrated by two‐dimensional imaging. Several lesions were also depicted in a unique fashion using this technique. Though the method employed was limited by movement artifact and reconstruction time, the quality of the three‐dimensional display was excellent and enhanced by realtime demonstration. The transthoracic approach was successful in capturing sufficient data to create three‐dimensional images, which may have further application in more accurate diagnosis of complex cardiac abnormalities and generation of planes of view which could duplicate surgical visualization of a lesion. Further assessment of the technique in infants with congenital heart disease is warranted.

Three‐Dimensional Speckle‐Tracking Echocardiography: Methodological Aspects and Clinical Potential

Speckle‐tracking echocardiography (STE) is an advanced echocardiographic technique that allows a novel approach to the assessment of cardiac physiology through the study of myocardial mechanics. In its three‐dimensional (3D) modality, it overcomes the drawbacks inherent to other echocardiographic techniques, namely two‐dimensional echocardiography and tissue Doppler imaging. Several research studies and software improvements have led 3D‐STE to become a promising tool for accurate evaluation of global and regional cardiac function. This article addresses the image acquisition, analytical methods, and parameters of myocardial mechanics that could be derived from 3D‐STE. This systematic guidance may help to establish its usefulness in the global and regional evaluation of cardiac function, and to facilitate its clinical application.

Usefulness of tricuspid annular velocity in identifying global RV dysfunction in patients with primary pulmonary hypertension: a comparison with 3D echo-derived right ventricular ejection fraction.

While right ventricular (RV) function and size are important clinical markers in several cardiac conditions, the assessment of RV function by two‐dimensional (2D) echocardiography remains challenging, due to the complexity of RV geometry. We therefore sought to compare an easily‐measured parameter, peak systolic velocity of tricuspid annulus (TAPSV) obtained by tissue Doppler imaging (TDI), to right ventricular ejection fraction (RVEF) measured by real time three‐dimensional echocardiography (RT3DE) and to explore what TAPSV cutoff values would be useful in detecting global RV dysfunction. We enrolled 20 patients affected by primary pulmonary hypertension and 30 consecutive healthy volunteers, who underwent transthoracic echocardiography, RT3DE and tissue Doppler evaluation. TAPSV had a statistically significant correlation with RVEF (r = 0.66, P < 0.001). With RV dysfunction defined as RVEF <40%, a TAPSV cutoff value of 9.5 cm/sec yielded the best compromise between sensitivity, specificity, and positive predictive value and negative predictive value. In conclusion, a TAPSV cutoff value of 9.5 cm/sec yields significantly high sensitivity and specificity and appears to be a valid compromise in detecting RV dysfunction, TAPSV values however are not useful in evaluating the severity of RV dysfunction.

Quantification of Right Ventricular Volumes and Function by Real Time Three‐Dimensional Echocardiographic Longitudinal Axial Plane Method: Validation in the Clinical Setting

Background: Measurement of right ventricular (RV) volumes and right ventricular ejection fraction (RVEF) by three‐dimensional echocardiographic (3DE) short‐axis disc summation method has been validated in multiple studies. However, in some patients, short‐axis images are of insufficient quality for accurate tracing of the RV endocardial border. This study examined the accuracy of long‐axis analysis in multiple planes (longitudinal axial plane method) for assessment of RV volumes and RVEF. Methods: 3DE images were analyzed in 40 subjects with a broad range of RV function. RV end‐diastolic (RVEDV) and end‐systolic volumes (RVESV) and RVEF were calculated by both short‐axis disc summation method and longitudinal axial plane method. Results: Excellent correlation was obtained between the two methods for RVEDV, RVESV, and RVEF (r = 0.99, 0.99, 0.94, respectively; P < 0.0001 for all comparisons). Conclusion: 3DE longitudinal‐axis analysis is a promising technique for the evaluation of RV function, and may provide an alternative method of assessment in patients with suboptimal short‐axis images.

Feasibility and clinical impact of live three-dimensional echocardiography in the management of congenital heart disease.

Background: Precise assessment of congenital heart lesions requires inferential evaluation from multiple two‐dimensional echocardiographic images (2DE). The aim of our study was to assess the usefulness of transthoracic live three‐dimensional echocardiography (3DE) in the evaluation of congenital heart disease. Methods: Eighty‐two patients (from 4 months to 31 years, mean age 12 ± 7.5, 38 males and 44 females), known to have congenital heart lesions, prospectively underwent both 2DE and 3DE. Conventional data acquisition by 2DE and “full volume” 3DE acquisition (apical four chambers, parasternal long and short axes, subcostal windows) were carried out by two independent and blinded operators. Data derived from 3DE were compared to 2DE, and 3DE results were graded into three categories: (A) new findings not seen on 2D echo studies, but not critical to therapeutic decision making; (B) additional anatomic information useful in therapeutic decision making; and (C) information equivalent to 2D echo studies. Results: Two out of 82 patients (2%) were excluded because of suboptimal 3DE images. In comparison with 2DE studies, 3DE was graded A in 23 patients (29%), B in 28 patients (35%), and C in 29 patients (36%). In the patients with group B results, atrial and ventricular septal defects, endocardial cushion defects, and l‐transposition of great vessels were the most represented pathologies in which 3DE aided medical or surgical therapeutic options. While the new findings in group A did not influence therapy, they defined the whole spectrum of abnormalities in those patients. In patients who fell under group C results, 3DE provided a direct realistic display of the pathology detected by 2DE. Conclusions: Our study demonstrates that live 3DE, easily performed at the bedside, provides incremental information on patients with a variety of congenital heart lesions. In the clinical scenario, it clarifies the pathology in all its dimensions, particularly in complex lesions with the incremental information having impact on therapeutic decision making.

Doppler Echocardiographic Findings in Pericardial Tamponade and Constriction

Abnormalities of the pericardium and/or fluid accumulation in the pericardial space are frequent findings in hospitalized patients, especially in the era of widespread noninvasive cardiac assessment by echocardiography. Not uncommonly, a diagnostic difficulty arises in differentiating the mere presence of a pericardial abnormality from ohe that is hemodynamically significant (for example, constrictive pericarditis or cardiac tamponade). Although various physical and laboratory findings have been used in an attempt to determine whether a pericardial effusion or thickened pericardium have resulted in hemodynamic compromise, cardiac catheterization has traditionally been used for definitive confirmation prior to therapeutic interventions such as pericardial stripping or fluid drainage. Recently, Doppler echocardiography has been shown to be useful for documenting the intracardiac flow abnormalities related to constrictive pericarditis and cardiac tamponade.

Simultaneous Right and Left Atrial Appendage Thrombus in a Patient with Atrial Fibrillation: A Lesson to Remember

We report a case of simultaneous right and left atrial appendage thrombi in a 76‐year‐old‐man with atrial fibrillation. Although transesophageal echocardiography is considered a routine diagnostic procedure, complete and comprehensive visualization of both atrial appendages is of paramount importance, particularly with the introduction of new therapeutic options like left atrial appendage exclusion devices. We expect to raise awareness among clinicians of the prevalence and implications of bilateral atrial appendage thrombi in common clinical practice.

Left Ventricular Apex Involvement in Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a genetically transmitted disease with broad morphologic and clinical spectrum. The most common presentation involves asymmetric basal anteroseptal left ventricular (LV) hypertrophy with outflow tract obstruction due to systolic anterior motion of the mitral valve. Less common variants are represented by midventricular and apical HCM. These forms are usually defined “sub-basal HCM” and have been associated with apical aneurysm formation. There is no universal classification of the LV hypertrophy pattern in HCM. According to a “four-patterns” model proposed by Helmy SM, four different patterns of LV hypertrophy are identified: Pattern 1 (P1) is characterized by septal hypertrophy alone; pattern 2 (P2) involves the septum and adjacent segments but spares the apex; pattern 3 (P3) involves the apex in combination with other LV segments; and pattern 4 (P4) consists of an apical hypertrophy alone (Fig. 1). Isolated apical HCM (pattern 4) is a rare variant in the nonJapanese population (1–2%). We present three patients with HCM in whom the LV apex was involved in various patterns, reflecting the atypical localization of hypertrophy or the consequences of the mid-ventricular obstruction, and discuss the clinical implications of these rare variants. Clinical Cases: Case A: The patient was a 62-year-old male, with negative clinical history. He was diagnosed at our institution following electrocardiogram (ECG) for sport-related preparticipation screening, and was completely asymptomatic and event-free. The ECG showed T wave inversion and ST-T depression in leads V4–6, Lead 1 and aVL (Fig. 2A). Transthoracic echocardiography showed apical hypertrophy (maximum diastolic thickness: 22 mm) extending to the whole lateral wall (maximum diastolic thickness: 21 mm). There was no intraventricular obstruction. LV cavity volume was 64 ml/m2 (end-diastole) and 27 ml/m2 (end-systole) with LV ejection fraction (EF): 58% (Fig. 2B,C). Cardiac magnetic resonance (CMR) (Fig. 2D,E) confirmed the apical localization of hypertrophy and identified areas of late gadolinium enhancement (LGE) within the inferior wall which was hypokinetic. Because of this finding, the patient underwent computed tomographic coronary angiogram (CTA) that revealed a significant lesion of the proximal right coronary artery (RCA) and nonsignificant lesions of the circumflex and left anterior descending coronary artery (LAD). The proximal RCA lesion, confirmed by angiography, was treated by percutaneous intervention (PCI) because of a positive exercise stress echocardiogram. To date, he remains asymptomatic and in good health.