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Partho P Sengupta

Publications and source records attributed to Partho P Sengupta.

17 recordsLinked to original sources
PubMed2006

Left ventricular structure and function: basic science for cardiac imaging.

The myofiber geometry of the left ventricle (LV) changes gradually from a right-handed helix in the subendocardium to a left-handed helix in the subepicardium. In this review, we associate the LV myofiber architecture with emerging concepts of the electromechanical sequence in a beating heart. We discuss: 1) the morphogenesis and anatomical arrangement of muscle fibers in the adult LV; 2) the sequence of depolarization and repolarization; 3) the physiological inhomogeneity of transmural myocardial mechanics and the apex-to-base sequence of longitudinal and circumferential deformation; 4) the sequence of LV rotation; and 5) the link between LV deformation and the intracavitary flow direction observed during each phase of the cardiac cycle. Integrating the LV structure with electrical activation and motion sequences observed in vivo provides an understanding about the spatiotemporal sequence of regional myocardial performance that is essential for noninvasive cardiac imaging.

Aging↗
PubMed2005

Apex-to-base dispersion in regional timing of left ventricular shortening and lengthening.

OBJECTIVES: We investigated whether the onset and progression of regional left ventricular (LV) shortening and lengthening parallel the apex-to-base differences in depolarization and repolarization. BACKGROUND: Limited information exists regarding apex-to-base differences in longitudinal and circumferential deformation sequence of the LV. METHODS: The apex-to-base differences in electric activation and the progression of longitudinal and circumferential shortening and lengthening sequences were determined in 8 porcine beating hearts in situ by implanting bipolar electrodes and an array of 14 sonomicrometry crystals in the LV free wall. RESULTS: Electric activation started at the apical subendocardium and showed significant delay in reaching the LV base. The onsets of mechanical activation and subsequent 20%, 40%, and 80% peak longitudinal shortenings required longer time to occur at base compared to the apex. The repolarization sequence propagated in reverse, with the base repolarizing before the apex. Subendocardial longitudinal shortening at base and subepicardial circumferential shortening at apex continued beyond the period of LV ejection, resulting in an apex-to-base gradient in the onset of lengthening. This gradient correlated with the duration of isovolumic relaxation (r = 0.85, p = 0.004) and the time required for reaching the lowest LV diastolic pressure (r = 0.70, p = 0.04). CONCLUSIONS: Apex-to-base delay in mechanical shortening of LV parallels the apex-to-base direction of the electric activation sequence. Basal subendocardial and apical subepicardial regions deform through a characteristic phase of postsystolic shortening. Short-lived apex-to-base and subendocardial-to-subepicardial relaxation gradients at the onset of diastole may have a physiologic significance in facilitating active restoration of the LV cavity in diastole.

Animals↗
PubMed2005

Biphasic tissue Doppler waveforms during isovolumic phases are associated with asynchronous deformation of subendocardial and subepicardial layers.

Subendocardial and subepicardial layers of the left ventricle (LV) are characterized with right- and left-handed helical orientations of myocardial fibers. We investigated the origin of biphasic deformations of the LV wall during isovolumic contraction (IVC) and relaxation (IVR). In eight open-chest adult pigs, strain rates were measured along the right- and left-handed helical directions in the LV anterior wall by implanting 16 sonomicrometry crystals. Sonomicrometry strain rates were compared with the longitudinal subendocardial strain rates obtained by tissue Doppler imaging. During ejection and diastolic filling, shortening and lengthening occurred synchronously along the right- and left-handed helical directions. However, during IVC and IVR, the deformations were dissimilar in the two directions. Transmural shortening during IVC occurred along the right-handed helical direction and was accompanied with transient lengthening in the left-handed helical direction. Conversely, during IVR, the LV lengthened along the left-handed helical direction and shortened in the right-handed helical direction. Peak subendocardial strain rates obtained by tissue Doppler imaging during IVC and IVR correlated with corresponding sonomicrometry strain rate values obtained along the right- and left-handed helical directions (r = 0.81, P < 0.001 and r = 0.70, P = 0.001, respectively). Our data suggest that brief counterdirectional movements occur within the LV wall during IVC and IVR. Shortening along the right-handed helical direction is accompanied with reciprocal lengthening in the left-handed helical direction during IVC and vice versa during IVR. The results support an association between asynchronous deformation of subendocardial and subepicardial muscle fibers and the biphasic isovolumic movements observed with high-resolution tissue Doppler imaging.

Animals↗
PubMed2005

Role of biplane echocardiography in a large-volume clinical practice: revamping strategies for echocardiography in a limited time.

OBJECTIVES: We determined the feasibility, learning curve, time efficacy, and the quality of imaging during biplane echocardiography performed in clinical practice with a view to reduce a sonographer's time for image acquisition. BACKGROUND: Multidimensional echocardiographic imaging has improved the assessment of cardiac geometry and function in clinical settings. However, concerns regarding ease of performance and effects on overall clinical work flow remain inadequately addressed. METHODS: The study included 100 consecutive unselected patients referred to our echocardiography laboratory. They were randomized to conventional or biplane echocardiography performed by a sonographer without previous knowledge of biplane imaging. Image acquisition time and variables influencing the learning curve and overall image quality were analyzed. RESULTS: Mean time required for biplane and mono-plane imaging was not different in the first 24 cases. In the remaining cases, mean image acquisition time was reduced significantly in 58 cases (76.3%): biplane, 5.6 minutes (SD 1.3); and monoplane, 6.6 minutes (SD 1.6) ( P = .0003). For both techniques, scanning time was not affected by referral pattern, body habitus, or underlying cardiac lesion. Overall, biplane scanning resulted in reduction in echocardiographic imaging time of 9.1%, maintaining an acceptable image quality in 87% of patients. In the last 20 cases, new software design and superior instrumentation technique improved the mean time gain to 15%. CONCLUSION: In a high-volume echocardiography laboratory, biplane imaging effectively reduces sonographer time for imaging and improves throughput by increasing the number of comprehensive ultrasound studies that can be performed in a limited time.

Cardiovascular Diseases↗
PubMed2005

Doppler tissue imaging improves assessment of abnormal interventricular septal and posterior wall motion in constrictive pericarditis.

We hypothesized that Doppler tissue imaging in the short axis would provide enhanced quantitative information for differentiating the pattern and extent of abnormal septal and posterior wall motion in constrictive pericarditis (CP). Using quantitative pulsed wave and color M-mode Doppler tissue imaging, we quantified the pattern of abnormal septal and posterior wall motion and studied its incremental advantage over conventional M-mode and 2-dimensional echocardiography in 40 patients with surgically proven CP. The pattern and extent of abnormalities were compared with 35 age- and sex-matched control subjects and 20 patients with abnormal septal motion of other causes. In 33 patients (82.5%) with CP, the interventricular septum showed high-velocity (>7 cm/s) early diastolic biphasic motion with or without multiple recoil waves (polyphasic diastolic septal fluttering). In the posterior wall, the early diastolic wave was normal but the late diastolic wave was reduced in 24 patients (60%) and absent in 7 (17.5%). In comparison, M-mode and 2-dimensional echocardiography identified abnormal septal or posterior wall motion in 24 patients (60%) ( P = .003). The pattern of abnormal septal motion in CP could be differentiated from abnormal septal motion of other causes in 16 patients (80%). The overall sensitivity and specificity of high-velocity polyphasic septal flutter for differentiating CP from control cases and other diseases was 82.5% and 92.7%, respectively. In CP, Doppler tissue imaging in the short axis provides unique diagnostic information and reliably differentiates CP from control cases and most other causes of abnormal septal motion.

Adult↗
PubMed2005

Quantification of regional nonuniformity and paradoxical intramural mechanics in hypertrophic cardiomyopathy by high frame rate ultrasound myocardial strain mapping.

This study tested the hypothesis that linear mapping of regional myocardial strain comprehensively assesses variations in regional myocardial function in hypertrophic cardiomyopathy. Hypertrophic cardiomyopathy is characterized by disorganized myocardial architecture that results in spatial and temporal nonuniformity of regional function. Left ventricular deformation was quantified in 20 patients with hypertrophic cardiomyopathy and compared with 25 age- and sex-matched control subjects. Abnormalities in subendocardial strain ranged from reduced longitudinal shortening to paradoxical systolic lengthening and delayed regional longitudinal contractions that were often located in small subsegmental areas. These variations were underestimated significantly by arbitrary measurements compared with linear mapping, in which a region of interest was moved across the longitudinal length of left ventricle (difference of peak and least strain, 10.7% +/- 5.1% vs 17% +/- 5.5%; P < .001). Echocardiographic assessment of variations in regional strain requires careful mapping and may be inappropriately assessed if left ventricular segments are sampled at arbitrary focal locations.

Adult↗
PubMed2005

Two-dimensional strain--a Doppler-independent ultrasound method for quantitation of regional deformation: validation in vitro and in vivo.

BACKGROUND: A new 2-dimensional strain echocardiography (2DSE) method has been introduced that measures myocardial deformations by tracking localized acoustic markers. We compared strains measured in vitro and in vivo by 2DSE with those obtained by sonomicrometry. METHODS: For the in vitro study, a tissue-mimicking gelatin block was cyclically compressed and longitudinal strains obtained by 2DSE and sonomicrometry crystals. For the in vivo study, arrays of crystals were implanted into the apical anteroseptal (test region) and midposterior (control region) in 16 open-chest pigs and strains measured by 2DSE and crystals at baseline and after acute ischemia. RESULTS: In vitro, pooled data demonstrated good correlation (r = 0.99, P < .0001) and close agreement (bias +/- 2SD = 0.7 +/- 2.2%) of 2DSE and sonomicrometry. For a combination of low testing strains (5.4%) and strain rates (0.8 and 1.2 Hz), 2DSE overestimated strains by sonomicrometry. In vivo, linear regression analysis of pooled measurements demonstrated again a good correlation (r = 0.94, P < .0001) and agreement (1.1 +/- 7.5%) of 2DSE with sonomicrometry with a trend toward lower absolute values of strains by 2DSE. CONCLUSION: The 2DSE demonstrated good overall correlation and agreement with sonomicrometry for the tested in vitro and in vivo values. Some caution with 2DSE measurements is needed for combinations of low strains and strain rates.

Animals↗
PubMed2004

Comparison of echocardiographic features of noncompaction of the left ventricle in adults versus idiopathic dilated cardiomyopathy in adults.

Noncompaction of left ventricular myocardium (NCLV), or "spongy myocardium," in adults represents an arrest in endomyocardial morphogenesis and occurs as an isolated cardiomyopathy. Because NCLV can be readily mistaken for idiopathic dilated cardiomyopathy, echocardiographic features other than the structural features of the myocardial wall need to be carefully defined for distinguishing the 2 conditions. This study was therefore designed to characterize the echocardiographic features that could be useful for differentiating NCLV from idiopathic dilated cardiomyopathy.

Adult↗
PubMed2004

Accuracy and pitfalls of early diastolic motion of the mitral annulus for diagnosing constrictive pericarditis by tissue Doppler imaging.

Mitral annular velocities are reportedly useful in diagnosing constrictive pericarditis (CP); however, their exact efficacy in larger clinical settings remains unevaluated. This study reexamined the role of longitudinal tissue Doppler imaging in diagnosing CP in clinical practice. Tissue velocity imaging (GE Vingmed System Five) was performed in 122 subjects (87 referred with clinically suspected CP and 35 age- and sex-matched controls). Of the 87 subjects with suspected CP, 45 (51.7%) had CP confirmed at surgery, 11 (12.6%) had restrictive heart disease, 20 (23.0%) had right heart failure due to cor pulmonale, and the other 11 (12.6%) had old pericardial effusions and no hemodynamic evidence of constriction on follow-up echocardiography. Of the 45 patients with CP, mitral early diastolic (Ea) annular velocities from septal and lateral regions were normal (>/=8 cm/s) in 40 (88.9%) and decreased (<8 cm/s) in 1 or both regions in 5 (3 with left ventricular systolic dysfunction, 2 with extensive mitral annular calcification). Of 11 patients with restrictive cardiomyopathy, 8 (72.7%) had reduced Ea (<8 cm/s) and 3 showed normal Ea velocity in 1 or both corners of the mitral annulus. All except 2 patients with right-sided heart failure from cor pulmonale and those with previous pericardial effusion had normal Ea velocities. A normal Ea velocity improved recognition of CP, particularly in the presence of nondiagnostic 2-dimensional or transmitral flow-Doppler imaging. The overall sensitivity and specificity for diagnosing CP using tissue Doppler incrementally with M-mode, 2-dimensional, and transmitral flow Doppler were 88.8% and 94.8%, respectively. Mitral annular velocities help with diagnosis and differentiation of CP in most cases, except in the presence of extensive annular calcification, left ventricular systolic dysfunction, or segmental nonuniformity in myocardial velocities.

Adult↗
PubMed2004

Regional dyssynergy of the interventricular septum after septal artery occlusion in hypertrophic obstructive cardiomyopathy: use of quantitative Doppler tissue and strain rate imaging.

We report the regional myocardial mechanics of the interventricular septum in a patient with hypertrophic obstructive cardiomyopathy undergoing therapeutic septal artery occlusion. Myocardial velocities improved across the entire septum; however, strain rate imaging showed the presence of severe regional dyssynergy.

Adult↗
PubMed2004

Effects of percutaneous mitral commissurotomy on longitudinal left ventricular dynamics in mitral stenosis: quantitative assessment by tissue velocity imaging.

OBJECTIVE: We hypothesized that mitral annular velocities would improve immediately after relief of mitral stenosis and that serial assessment could be used as an index for quantifying functional changes after percutaneous mitral commissurotomy (PMC). METHODS: Longitudinal left ventricular annular velocities were quantified by spectral pulsed wave Doppler tissue velocity imaging in 25 patients (16 women; mean age [+/-SD], 29.2 +/- 8.6 years) who had isolated mitral stenosis and were in sinus rhythm, and were compared with 30 age- and sex-matched control subjects. Echocardiography was performed 1 to 24 hours before PMC and 48 to 72 hours after, and changes in velocities from the lateral and septal corners of the mitral annulus in early diastole, late diastole, isovolumic contraction, and ejection were recorded. RESULTS: Systolic and diastolic mitral annular velocities were significantly less in patients with mitral stenosis than in control subjects. After PMC, peak annular velocity of systolic excursion in ejection and peak annular velocity in early diastole showed significant improvement. The change in peak annular velocity in early diastole in the lateral wall correlated well with improvement in the mitral valve orifice area by planimetry (ratio of mitral valve orifice area, 1.92 +/- 0.42; ratio of peak annular velocity in early diastole, 1.36 +/- 0.22; r = 0.65; P <.001). CONCLUSION: Serial evaluation of changes in mitral annular velocities by Doppler tissue imaging aids clinical assessment of immediate improvement in left ventricular function after PMC.

Adult↗
PubMed2004

Regional myocardial function in an arrhythmogenic milieu: tissue velocity and strain rate imaging in a patient who had hypertrophic cardiomyopathy with recurrent ventricular tachycardia.

We report the use of tissue velocity and strain rate imaging for detecting marked segmental variations and asynchrony in left ventricular systolic and diastolic functions of a 40-year-old patient with hypertrophic obstructive cardiomyopathy who died of an intractable ventricular tachycardia. These newer techniques have advantages for identifying heterogeneity in regional myocardial function in hypertrophic cardiomyopathy.

Adult↗
PubMedDate not supplied

Chlamydia pneumoniae infection and nonspecific aortoarteritis: search for a link with a nonatherosclerotic inflammatory arterial disease.

BACKGROUND: The association between Chlamydia pneumoniae infection and atherosclerosis has gained recognition. However, the nature of this association is controversial. The infective link may not be specific for atherosclerosis and may also exist in other nonatherosclerotic arterial diseases. We investigated patients with nonspecific aortoarteritis for serological evidence of prior Chlamydia pneumoniae infection. METHODS AND RESULTS: Fifty patients each of nonspecific aortoarteritis and coronary artery disease with angiographic evidence of significant (>70%) coronary artery lesions were tested for the presence of IgG antibodies against Chlamydia pneumoniae by micro-immunofluorescence assay and compared with 50 age- and sex-matched normal healthy controls. The number of patients with nonspecific aortoarteritis who tested positive for Chlamydia pneumoniae antibodies (IgG) was not significantly different from controls (8 v. 7, p=ns). The mean titer amongst positive subjects in the two groups was also similar (1:40+/-40 v. 1:50+/-25; p=ns). Patients with coronary artery disease were significantly older than patients with nonspecific aortoarteritis and controls (53.2+/-5.8 v. 21.2+/-9.9 years and 24.5+/-5.2 years, p<0.01 for both) and showed a higher seroprevalence of prior Chlamydia pneumoniae infection (18 v. 8 and 7, p < 0.05 for both). The mean IgG titers of patients with coronary artery disease who tested positive were also significantly higher than the other two groups (1:98+/-34 v. 1:40+/-40, p<0.001 and 1:98+/-34 v. 1:50+/-25, p<0.01, respectively). CONCLUSIONS: In patients with nonspecific aortoarteritis, the seroprevalence of prior Chlamydia pneumnoniae infection is not more than that in healthy individuals of the same age group, but is significantly lesser than that in patients with coronary artery disease. Thus Chlamydia pneumoniae infection may not be associated with all forms of chronic inflammatory arterial lesions.

Adolescent↗
PubMedDate not supplied

Left ventricle dynamics during pulsus alternans: insights from tissue velocity imaging.

A 34-year-old female patient with idiopathic dilated cardiomyopathy presented with hemodynamic pulsus alternans. Mitral annular tissue Doppler velocities showed reciprocal beat-to-beat alterations during systolic ejection and diastolic filling periods. Tissue velocity waves were unaltered during the isovolumic relaxation and contraction periods.

Adult↗
PubMedDate not supplied

Tissue Doppler echocardiography: principles and applications.

Tissue velocity imaging is an important development in the field of cardiac ultrasound that provides quantitative information for analysis of myocardial motion independent of the quality of gray-scale 2-D echocardiography data. It holds promise to reduce inter- and intraobserver variability in regional wall motion interpretation and is likely to improve the accuracy and reproducibility of stress echocardiography and myocardial viability assessment. It also enables regional diastolic function assessment independent of the loading conditions and offers a practical clinical tool to differentiate pathologic from physiologic myocardial hypertrophy, restrictive cardiomyopathy from constrictive pericarditis and for monitoring and selecting therapies in patients with advanced heart failure. The use of tissue velocity data for myocardial strain and strain rate imaging is likely to circumvent the limitations of tissue velocity in differentiating active and passive motion of a myocardial segment. However, its incremental utility and exact role in improving the diagnostic yield and clinical outcome needs to be addressed in future studies.

Coronary Disease↗