The impact of frame numbers on cardiac ECG-gated SPECT images with interpolated extra frames using echocardiography.

Background: Cardiac echocardiography and cardiac ECG-gated single-photon emission computed tomography (SPECT) are the most common modalities for left ventricle (LV) volumes and function assessment. The temporal resolution of SPECT images is limited and an ECG provides better temporal resolution. This study investigates the impact of frame numbers on images in terms of qualitative and quantitative assessments. Methods: In this study, 5 patients underwent echocardiography and cardiac ECG-gated SPECT imaging, and 5 standard views of the LV were recorded to determine LV walls boundaries and volumes. Also, 2 original images with 8 frames and 16 frames per cardiac cycle were recorded simultaneously in a single gantry orbit. Using the data extracted from the LV model, 8 extra new frames were created with interpolation between existing frames of the original 8-frame image. Three series of images (8 and 16 original and 16 interpolated) were reconstructed separately. LV volumes and ejection fraction (EF) were calculated using Quantitative Gated SPECT (QGS) software. Results: Compared to the original 8-frame gating, original 16-frame gated images resulted in larger end-diastole volume (EDV) (mean ± SD: 68.6 ± 27.11 mL vs 66.2±25.41 mL, p<0.001), smaller end-systole volume (ESV) (mean ± SD: 24.6±8.7 mL vs 26±7.3 mL, p<0.001), and higher EF (64% vs 60.2%, p<0.001). The results for the interpolated series were also different from the original images (closer to the original 16-frame series rather than 8-frame). Conclusion: Changing the frame number from 8 to 16 in cardiac ECG-gated SPECT images caused a significant change in LV volumes and EF. Frame interpolation with sophisticated algorithms can be used to improve the temporal resolution of SPECT images.

Left ventricular torsional parameters before and after atrial fibrillation ablation: a velocity vector imaging study.

BACKGROUND AND AIM: Effects of atrial fibrillation (AF) and its ablative treatment on LV torsion have not yet been fully investigated. This study aimed to examine whether AF patterns of LV contraction and its ablative correction can exert a significant impact on LV torsion by velocity vector imaging (VVI). METHODS: This case-control study conducted in Rajaie Cardiovascular, Medical and Research Center between October 2012 and June 2013. Study participants were 30 consecutive patients with symptomatic paroxysmal AF who met the inclusion criteria. The control group included 24 healthy participants with no history of cardiovascular disease. All individuals were in sinus rhythm at the time of echocardiography before and after the ablation procedure. Two-dimensional (2D) and Doppler echocardiography on a commercially available ultrasound system was performed for all the patients. Scanning was done by a wide-band ultrasound transducer with the frequency range between 2.5-3.5 MHz. The two short-axis views at basal and apical levels were subsequently processed off-line by VVI XStrain software. In order for data analysis, SPSS 16 utilized using paired and independent t-test. p-value ≤0.05 was considered significant. RESULTS: LV torsion (°/cm) mean ± SD was significantly lower in paroxysmal AF patients before ablation (0.8±0.3) than the control group (1.5±0.4) (p<0.001) and increased significantly after ablation (1.1±0.5) compared with before ablation (p=0.004), but still significantly lower than the control group (p=0.003). LV Twist, twist rate and untwist rate mean ± SD were significantly lower in paroxysmal AF patients before ablation than the control group and increased significantly after ablation compared with before ablation, but still significantly lower than the control group. CONCLUSION: Subclinical LV dysfunction may be detected in paroxysmal AF rhythm by measuring torsional parameters through VVI which improves after AF ablation.

Diagnostic Pitfalls and Challenges in Interpretation of Heart Transplantation Rejection in Endomyocardial Biopsies With Focus on our Experience.

BACKGROUND: The current trend of heart transplantation in recent years has taken a quantum leap forward. We decided to look back at our experience in this center. OBJECTIVES: Here, we focus on the diagnostic pitfalls and challenges in these biopsies. PATIENTS AND METHODS: Forty two patients based on the standard protocol of heart transplantation group, yielded 63 biopsy samples over a period of 33 months (April 2010 - December 2012). The mean age was 30.4 years (ranging from 16 to 58 years) with 51 males (81%) and 12 females (19%). All the patients were examined periodically and biopsy samples were taken from the right ventricular wall. RESULTS: Rarely fewer than three pieces of myocardial samples were procured. Scar, adipose tissues and blood clots may be seen instead. Quilty effect (nodular endocardial lesions composed of inflammatory cell infiltrates) was seen in 8 cases (12.7%). Other findings not directly related to rejection including early ischemic injury, Quilty effect and post-transplant lymphoproliferative disorders (PTLD) were not encountered. CONCLUSIONS: Specimen inadequacy was not a major problem in our center. It poses a great limitation, because suboptimal specimens sometimes mislead the pathologist. Other findings especially Quilty effect were within the range defined for this finding.

Impact of metabolic syndrome on mortality and morbidity after coronary artery bypass grafting surgery.

BACKGROUND: The prevalence of Metabolic syndrome (MetS) has been increased in Asian countries. It represents a cluster of cardiovascular risk factors including obesity, insulin resistance, lipid abnormality and hypertension. OBJECTIVES: The purpose of this study was to assess the association between MetS and outcome in patients undergoing coronary artery bypass grafting surgery (CABG). PATIENTS AND METHODS: This prospective study was performed on patients scheduled for coronary artery bypass grafting surgery (CABG). All the patients were followed up in hospital and three months afterward. Patients were excluded if they were younger than 18 years or had severe comorbidities, a history of valvular heart disease, and low ejection fraction. RESULTS: A total of 235 patients (135 women) with a mean age of 59 ± 9.3 years were included. MetS was more prevalent in women (P < 0.001). The most prevalent complications were bleeding [20 (8.5%)] and dysrhythmia [18 (7.7%)]. At three months follow-up, the frequency rates of readmission [24 (10.2%)] and mediastinitis [9 (3.8%)] were higher than other complications. Diabetes and MetS were risk factors for a long ICU stay (> 5 days) and atelectasia (P < 0.05). Significant associations were observed between diabetes and pulmonary embolism (P = 0.025) and mediastinitis (P = 0.051). CONCLUSIONS: Identification of MetS before CABG can predict the surgery outcome. Patients with MetS have increased risks for longer ICU stay and atelectasia.

Effect of obesity on mortality and morbidity after coronary artery bypass grafting surgery in Iranian patients.

BACKGROUND: Recent years have witnessed the emergence of obesity as a major public health concern. The drastic rise in obesity and its concomitant co-morbidities is a reflection of the recent changes in dietary habits in Iran and many other developing countries. A recent large population study in Tehran reported that 58% and 75% of middle-aged Iranian men and women, respectively, were either overweight or obese. OBJECTIVES: Considering the impact of obesity on mortality and morbidity after coronary artery bypass graft surgery (CABG), we sought to investigate the association between central obesity and the body mass index (BMI) and the post-CABG mortality and morbidity in Iranian patients. PATIENTS AND METHODS: This prospective study was on 235 adult patients scheduled for isolated CABG in a university hospital. The patients were divided in two groups according to BMI ≥ 30 (obese; n = 60) and BMI < 30 (non-obese; n = 175). In-hospital and late (after 3 months) morbidity and mortality rates were compared between obese and non-obese patients. RESULTS: A total of 235 patients (135 women) with a mean age of 59 ± 9.2 years (range = 29 to 79 years), mean BMI of 27.3 ± 4.2 (range = 17 to 40), and mean waist circumference of 101.2 ± 14.7 cm (range = 55 to 145 cm) were included. By the third postoperative month, wound infection had significantly increased in patients with BMI ≥ 30 (P = 0.022). In-hospital and late morbidity and mortality rates were comparable between the two groups (P > 0.05). CONCLUSIONS: In our patients obesity was a risk factor for wound infection but not atelectasis or the need for intra-aortic balloon pump or re-exploration. Obesity was not associated with increased in-hospital or 3 months mortality rates after CABG.

Assessment of subclinical left ventricular dysfunction in patients with chronic mitral regurgitation using torsional parameters described by tissue Doppler imaging.

BACKGROUND: Left ventricular (LV) twist is due to oppositely directed apical and basal rotation and has been proposed as a sensitive marker of LV function. We sought to assess the impact of chronic pure mitral regurgitation (MR) on the torsional mechanics of the left human ventricle using tissue Doppler imaging. METHODS: Nineteen severe MR patients with a normal LV ejection fraction and 16 non-MR controls underwent conventional echocardiography and apical and basal short-axis color Doppler myocardial imaging (CDMI). LV rotation at the apical and basal short-axis levels was calculated from the averaged tangential velocities of the septal and lateral regions, corrected for the LV radius over time. LV twist was defined as the difference in LV rotation between the two levels, and the LV twist and twisting/untwisting rate profiles were analyzed throughout the cardiac cycle. RESULTS: LV twist and LV torsion were significantly lower in the MR group than in the non-MR group (10.38° ± 4.04° vs. 13.95° ± 4.27°; p value = 0.020; and 1.29 ± 0.54 °/cm vs. 1.76 ± 0.56 °/cm; p value = 0.021, respectively), both suggesting incipient LV dysfunction in the MR group. Similarly, the untwisting rate was lower in the MR group (-79.74 ± 35.97 °/s vs.-110.96 ± 34.65 °/s; p value = 0.020), but there was statistically no significant difference in the LV twist rate. CONCLUSION: The evaluation of LV torsional parameters in MR patients with a normal LV ejection fraction suggests the potential role of these sensitive variables in assessing the early signs of ventricular dysfunction in asymptomatic patients.

Evaluation of left anterior descending coronary artery stenosis severity from myocardial end-diastolic wall stress estimated by tissue-Doppler imaging.

PURPOSE: To identify patients with significant coronary artery disease by the noninvasive quantification of myocardial wall stress in diastole. METHODS: We studied 60 male subjects in sinus rhythm with significant (n = 30) or moderate (n = 30) proximal left anterior descending coronary artery stenosis, and 30 healthy subjects (control group). The average end-diastolic wall stress was estimated at left ventricle anterior and interventricular septum wall segments from regional wall thickness, meridional and circumferential regional radii of curvature, and noninvasively estimated left ventricular end-diastolic pressure. RESULTS: There were significant differences in left ventricular end-diastolic pressure between patients and controls (p < 0.05). End-diastolic myocardial wall stress was significantly different between patients with significant and moderate coronary stenosis and healthy subjects in all anterior and septal wall segments (p < 0.05) except for the anterior wall at mid level. The receiver-operating characteristic curves showed that septum apex wall stress has the highest discriminatory power for predicting significant stenosis versus healthy coronary artery with 83% area under the curve. CONCLUSIONS: Estimated end-diastolic myocardial wall stress may help in evaluating regional myocardial dysfunction due to coronary artery disease.

Utility of right ventricular strain imaging in predicting pulmonary vascular resistance in patients with pulmonary hypertension.

Pulmonary vascular resistance (PVR) has important prognostic implications in the assessment of patients with pulmonary hypertension. Using echocardiography to measure PVR would have the advantage of being able to follow patients serially and to assess their response to treatment noninvasively. The authors sought to assess whether right ventricular strain rate imaging (SRI) can predict PVR in patients with pulmonary hypertension. The study population consisted of 46 patients referred for right heart catheterization. The inclusion criteria was mean pulmonary artery pressure ≥25 mm Hg in right heart catheterization in patients with pulmonary hypertension including chronic systolic heart failure. Echocardiography was performed to obtain SRI just before right heart catheterization. Mean values of peak systolic longitudinal strain and strain rate obtained from basal and mid-right ventricular free wall were calculated. The control group consisted of 35 healthy adults matched for age and sex. The most significant correlations were between basal right ventricular strain and strain rate (SR) and mean pulmonary arterial pressure (r=0.63, P=.000), transpulmonary gradient (r=0.6, P=.001), and PVR (r=0.5, P=.003). SR was independently correlated with PVR (PVR=26.9-16.9×basal right ventricular SR; r=0.53, P=.003). The present study shows that basal right ventricular free wall strain and SR could be independently correlated with PVR in patients with pulmonary hypertension.

Assessment of Inter and Intra-atrial Asynchrony in Patients with Systolic Heart Failure Using Velocity Vector Imaging.

BACKGROUND: According to previous studies on the deformation properties of the left atrium, the systolic strain and strain rates represent the atrial reservoir function and the early and late diastolic strain rates show the conduit and booster functions, respectively. OBJECTIVES: We sought to evaluate the intra and interatrial asynchrony using strain/strain rate imaging in systolic heart failure patients. PATIENTS AND METHODS: Twenty five patients with systolic heart failure (LVEF ≤ 40%) were enrolled into the study. Asynchrony quantifications were performed according to the standard deviation of time-to peak (TP-SD) of deformation of three segments manually located along the perimeter of the left atrium free wall, right atrium free wall and interatrial septum, as imaged in an apical four-chamber view. We also calculated classic echocardiography parameters such as LV end-diastolic dimension index, LA volume index, RA area, as well as deceleration time (DT) on transmitral pulsed wave Doppler and E/E' ratio on mitral annular tissue Doppler imaging. RESULTS: In heart failure patients either inter or intra-atrial asynchrony were far more common in comparison with normal subjects (P=0.008 and P=0.007 respectively). CONCLUSIONS: Left ventricular systolic heart failure, may result in inter and intra-atrial asynchrony even in clinically stable patients without significant pulmonary hypertension and diastolic dysfunction.

Coronary flow reserve, strain and strain rate imaging during pharmacological stress before and after percutaneous coronary intervention: comparison and correlation.

INTRODUCTION: Coronary flow reserve (CFR) could apply reliable information about the coronary circulation, and strain (S) and strain rate imaging (SRI) are able to quantify the left ventricular myocardial performance. The aim of this study was to assess myocardial performance in relation to the function of the coronary circulation before and after successful percutaneous coronary intervention (PCI) of the left anterior descending artery. MATERIAL AND METHOD: Fourteen patients (10 men, 4 women, mean age 53.2 ± 11.4 years) with severe left anterior descending stenosis who had a successful selective PCI were recruited into this study. CFR and myocardial deformity indices (S and SR) were recorded before and after percutaneous intervention, both at rest and during stress echo test. RESULTS: CFR, S, and SR increased after intervention significantly. There was significant correlation between CFR ratio and poststress systolic strain (SS) ratio and early diastolic strain rate (ESR) ratio (P < 0.05 and r > 0.6). Also CFR improvement had significant relationship with changes of poststress Systolic SR and poststress Systolic S (P < 0.05 and r > 0.6). Based on regression analysis the amount of change in CFR was independently associated with change in SS during stress and systolic SR. CONCLUSION: PCI improves CFR (a marker of coronary perfusion), strain, and strain rate (markers of regional cardiac wall deformation). The independent association between CFR improvement and poststress systolic strain and strain rate means that SRI parameters can independently predict CFR changes after PCI.

Quantitative assessment of right atrial function by strain and strain rate imaging in patients with heart failure.

OBJECTIVES: We sought to evaluate the regional longitudinal strain/strain rate profiles in the right atrial wall to quantify right atrial function in systolic heart failure patients. BACKGROUND: According to previous studies on the deformational properties of the left atrium, the systolic strain and strain rates represent the atrial reservoir function and the early and late diastolic strain rates show the conduit and booster functions, respectively. METHODS: Thirty patients with a diagnosis of heart failure (left ventricular ejection fraction < or = 35%) scheduled for right heart catheterization were enrolled. Echocardiography was performed to obtain right atrial deformation indices just before the procedure. The control group consisted of 32 healthy adults matched for age and sex. The deformity indices obtained consisted of the right atrial peak systolic strain (RAS), right atrial peak systolic strain rate (RASSR), right atrial early diastolic strain rate (RAEDSR), and right atrial late diastolic strain rate (RALDSR). RESULTS: The right atrial deformation indices were significantly compromised in the heart failure patients versus the normal subjects (RAS: 68.5 +/- 53.9 vs 189.3 +/- 61.2, P = 0.000; RASSR: 2.9 +/- 1.9 vs. 5.3 +/- 1.5, P = 0.000).There was a significant correlation between the RAS and RASSR and cardiac output (RAS: r = 0.5, P = 0.005; RASSR: r = 0.5, P = 0.003), and cardiac index (RAS: r = 0.6, P = 0.001; RASSR: r = 0.6, P = 0.001). CONCLUSION: In light of our findings, we conclude that a diminished RA function, as assessed by strain imaging, plays a critical role in the pathophysiological process of heart failure patients.

Non-invasive assessment of coronary artery stenosis with estimation of myocardial wall stress.

BACKGROUND: More diagnostic techniques require a better understanding of the forces and stresses developed in the wall of the left ventricle. The aim of this study was to differentiate significant coronary artery disease (CAD) patients using a non-invasive quantification of myocardial wall stress in the diastole phase. METHODS: Sixty male subjects with sinus rhythm (30 patients with significant and 30 with moderate left anterior descending coronary artery stenosis in the proximal portion) as well as 35 healthy subjects as the control group were recruited into the present study. By two-dimensional, pulsed wave, and tissue Doppler echocardiography, the average end-diastolic wall stress was calculated at the left ventricle anterior and interventricular septum wall segments using regional wall thickness, meridional and circumferential radii, and non-invasive left ventricular end-diastolic pressure. RESULTS: A comparison of the calculated end-diastolic myocardial wall stress between the patients with significant and moderate coronary stenosis on the one hand and the healthy subjects on the other showed statistically significant differences in the anterior and septum wall segments (p value < 0.05). The patients with significant left anterior descending coronary artery stenosis had higher end-diastolic myocardial wall stress than did those with moderate stenosis and the healthy group in all the anterior and septum wall segments. CONCLUSION: It is concluded that non-invasive end-diastolic myocardial wall stress in coronary artery disease patients is an important index in evaluating myocardial performance.

Determination of instantaneous interventricular septum wall thickness by processing sequential 2D echocardiographic images.

Non-invasive quantitative analysis of the heart walls thickness is a fundamental step in diagnosis and discrimination of heart disease. Thickness measurements in 2D echocardiographic images have many applications in research and clinic for assessing of wall stress, wall thickening and viability parameters. Regarding to interventricular septum wall thickness measurement by conventional manual method is more dependent on sonographer experiment; this encouraged these researchers to develop a semi-automatic computer algorithm in accessing to interventricular septum segments thickness. We proposed and carried out a computerized algorithm for wall thickness measurements in 2D echocardiographic image frames. In this program, wall thickness measurement is based of intensity profile function and adaptive bilateral thresholding operation. For validation, thicknesses of septum base and mid segments were estimated in constituent image frames with use of proposed method and then were compared with conventional manual results at same images of the cardiac cycle by statistical methods. In our sample image frames (240 corresponding segments; with different rang of image quality), a bias of 0.10 and 0.12 mm with SD differences of +/-0.81 and +/-0.72 mm and correlation coefficients of 0.87 and 0.89 were found in base and mid segments, respectively. Interobserver variability using the Computer-Assisted Method (CAM) and Conventional Manual Method (CMM) were 4.0 and 4.7% for the basal and 2.8 and 3.9% for the middle segments. The method introduced in the present study permits precise thickness assessment of base and mid segments of the interventricular septum wall and has high concordance with CMM.