Evaluation of the right ventricle: Comparison of gated blood-pool single photon electron computed tomography and echocardiography with cardiac magnetic resonance

Evaluation of biventricular function by cadmium-zinc-telluride SPECT gated tomographic radionuclide angiography: Comparison to conventional SPECT

We compared and analyzed the consistency and repeatability of left and right ventricular ((LV/RV) functions obtained by gated-equilibrium radionuclide ventriculography (ERNV) with cadmium-zinc-telluride single-photon emission computed tomography (CZT-SPECT) and conventional SPECT (C-SPECT) with sodium iodide crystal detectors. Seventy-seven patients were included in the retrospective study. Both C-SPECT and CZT-SPECT imaging were performed on the same day. Correlations and differences in LV/RV ejection fraction (LVEF and RVEF), peak ejection rate (PER), and peak filling rate (PFR) were compared between the 2 models. Cardiac magnetic resonance (CMR) was partially used as the gold standard, and ultrasound results were included for comparative analysis. Interobserver reproducibility of each parameter obtained by the 2 cameras was compared. Between the 2 cameras, there were no significant difference in LVEF, LVPER, LVPFR, and RVPER (P > .05) and there were in RVEF and RVPFR (P < .05 or .001). The correlations (R value) were 0.831 (LVEF, excellent), 0.619 (RVEF, good), 0.672 (LVPER, good), 0.700 (LVPFR, good), 0.463 (RVPER, normal), and 0.253 (RVPFR, poor). There were no significant difference between CMR and CZT-SPECT in LVEF (P > .05) while there were between CMR and both C-SPECT and ultrasound (P < .05). The correlations were all good (R = 0.660, 0.658, and 0.695). There were no significant difference between CMR and both C-SPECT and CZT-SPET in RVEF (P > .05) and the correlations were good (R = 0.771 and 0.745). For repeatability, the intraclass correlation coefficient of RVPFR by C-SPECT was good (intraclass correlation coefficient = 0.698) and excellent for the rest of the groups (0.823-0.989). The repeatability of LVEF and RVEF was better for CZT-SPECT than for C-SPECT. The repeatability of PER was better for both cameras than PFR. CZT-SPECT tomographic ERNV correlated well with C-SPECT planar ERNV in evaluation of biventricular systolic function and LV diastolic function. Compared with the "gold standard" CMR, both models had good correlation in measuring LV/RVEF. CZT-SPECT had better inter-group reproducibility than C-SPECT. The accuracy of RV diastolic function need further study. CZT-SPECT tomographic ERNV will play an important and unique role in the clinical application of accurate evaluation of biventricular function in the future.

Comparison of Cadmium Zinc Telluride ECG-gated SPECT equilibrium radionuclide angiocardiography to magnetic resonance imaging to measure right ventricular volumes and ejection fraction in patients with cardiomyopathy

AIMS

The objective of this study was to determine the accuracy of right ventricular function (RVF) assessed by Cadmium Zinc Telluride ECG-gated SPECT equilibrium radionuclide angiocardiography (CZT-ERNA).

METHODS AND RESULTS

Twenty-one consecutive patients with cardiomyopathy (aged 54 ± 19 years; 62% male) were included. RV ejection fraction (EF) and volumes were analyzed by CZT-ERNA and compared with values obtained by cardiac magnetic resonance imaging (CMR). Mean values were not different between CZT-ERNA and MRI for RVEF (48.1 ± 10.4% vs 50.8 ± 10.0%; P = .23). Significant correlations (P < .0001) were observed between CZT-ERNA and MRI for RVEF, RV end-diastolic volume, and end-systolic volume (r = 0.81, r = 0.93, and r = 0.96, respectively). Bland-Altman analysis showed a mean difference (bias) between CZT-ERNA and MRI for RVEF of -2.69% (95% CI - 5.35 to - 0.42) with good agreement between the 2 techniques (limits of agreement, -14.3 to 8.99). Intraobserver and interobserver reproducibility of RVF measured by CZT-ERNA was high.

CONCLUSION

CZT-ERNA provides accurate, reproducible assessment of RVF and appears as a good alternative to cardiac magnetic resonance for the evaluation of the magnitude of RVF in patients with cardiomyopathy.

Right ventricular function and its coupling to pulmonary circulation predicts exercise tolerance in systolic heart failure

Aims

Right ventricular (RV) dysfunction, pulmonary hypertension, and exercise intolerance have prognostic values, but their interrelation is not fully understood. We investigated how RV function alone and its coupling with pulmonary circulation (RV‐PA) predict cardio‐respiratory fitness in patients with heart failure and reduced ejection fraction (HFrEF).

Methods and results

The Evaluation of Resynchronization Therapy for Heart Failure (EARTH) study included 205 HFrEF patients with narrow (n = 85) and prolonged (n = 120) QRS duration undergoing implantable cardioverter defibrillator implantation. All patients underwent a comprehensive evaluation with exercise tolerance tests and echocardiography. We investigated the correlations at baseline between RV parameters {size, function [tricuspid annular plane systolic excursion (TAPSE), RV fractional area change (RV‐FAC), and RV myocardial performance index (RV‐MPI)], pulmonary artery systolic pressure (PASP), and tricuspid regurgitation}; left ventricular ejection fraction (LVEF), left ventricular end‐diastolic volume index (LVEDVi), and left atrial volume index (LAVi); and cardiopulmonary exercise test (CPET) [peak VO₂, minute ventilation/carbon dioxide production (VE/VCO₂), 6 min walk distance (6MWD), and submaximal exercise duration (SED)]. We also studied the relationship between RV‐PA coupling (TAPSE/PASP ratio) and echocardiographic parameters in patients with both data available. Univariate and multivariate linear regression models were used. Patients enrolled in EARTH (overall population) were mostly male (73.2%), mean age 61.0 ± 9.8 years, New York Heart Association class II–III (87.8%), mean LVEF of 26.6 ± 7.7%, and reduced peak VO₂ (15.1 ± 4.6 mL/kg/min). Of these, 100 had both TAPSE and PASP available (TAPSE/PASP population): they exhibited higher BNP, wider QRS duration, larger LVEDVi, with more having tricuspid regurgitation compared with the 105 patients for whom these values were not available (all P < 0.05). RV‐FAC (β = 7.5), LAVi (β = −0.1), and sex (female, β = −1.9) predicted peak VO₂ in the overall population (all P = 0.01). When available, TAPSE/PASP ratio was the only echocardiographic parameter associated with peak VO₂ (β = 6.8; P < 0.01), a threshold ≤0.45 predicting a peak VO₂ ≤ 14 mL/kg/min (0.39 for VO₂ ≤ 12). RV‐MPI was the only echocardiographic parameter associated with ventilatory inefficiency (VE/VCO₂) and 6MWD (β = 21.9 and β = −69.3, respectively, both P ≤ 0.01) in the overall population. In presence of TAPSE/PASP, it became an important predictor for those two CPET (β = −18.0 and β = 72.4, respectively, both P < 0.01), together with RV‐MPI (β = 18.5, P < 0.01) for VE/VCO₂. Tricuspid regurgitation predicted SED (β = −3.2, P = 0.03).

Conclusions

Right ventricular function assessed by echocardiography (RV‐MPI and RV‐FAC) is closely associated with exercise tolerance in patients with HFrEF. When the TAPSE/PASP ratio is available, this marker of RV‐PA coupling becomes the stronger echocardiographic predictor of exercise capacity in this population, highlighting its potential role as a screening tool to identify patients with reduced exercise capacity and potentially triage them to formal peak VO₂ and/or evaluation for advanced HF therapies.

Tricuspid annular plane systolic excursion is dependent on right ventricular volume in addition to function

BACKGROUND

Tricuspid annular plane systolic excursion (TAPSE) is an effective parameter for assessing right ventricular (RV) function in echocardiographic studies. The preload dependency of TASPE has not been explored.

METHODS

We retrospectively reviewed 380 cardiac magnetic resonance (CMR) exams. RV ejection fraction (EF) and end-diastolic volume (EDV) were measured from short-axis cine images. TAPSE was measured as the difference of the perpendicular distance of the tricuspid annulus to the RV apex during diastole and systole. RV dysfunction was defined as RVEF <47%. The relationship of TAPSE, RVEF, and indexed RVEDV (RVEDVi) were evaluated. The TAPSE cut-off values derived from CMR were tested in a validation group (n = 46) with an echocardiographic exam performed within 1 month of the CMR.

RESULTS

TAPSE had a good linear correlation with RVEF (r = .69, P < .001). In normal RVEF patients, TAPSE had a positive correlation with RVEDVi (r = .208, P = .014). Receiver operating characteristic analysis revealed a higher TAPSE cut-off value of 2.4 cm in the top normal to mildly dilated RV volume group for identifying RV dysfunction with lower predictive accuracy (sensitivity 80%, specificity 67%, area under the curve = 0.78, P < .001) as compared with 2.0 cm for the normal RV size or moderate to severely dilated RV groups. The higher TAPSE cutoff showed improved sensitivity (73% vs 43%) and Youden index (0.55 vs 0.43) in our validation cohort.

CONCLUSIONS

Tricuspid annular plane systolic excursion not only correlates with RVEF, but also is dependent on RV volume. The cut-off value and predictive accuracy of TAPSE for detecting RV dysfunction vary with different RV volumes.

Tricuspid Annular Plane Systolic Excursion: Comparing Transthoracic to Transesophageal Echocardiography

OBJECTIVE

Tricuspid annular plane systolic excursion (TAPSE) represents movement of the lateral annulus of the tricuspid valve toward the apex and denotes right ventricular contractility in the long axis. In transesophageal echocardiography with the probe in the mid-esophagus, TAPSE occurs at a significant angle to the M-mode scan line. The authors describe a novel method to assess TAPSE in 2 dimensions (2D) and compare this with an established method.

DESIGN

Prospective cohort study.

SETTING

Tertiary cardiac unit.

PARTICIPANTS

Forty-three patients scheduled for outpatient transesophageal echocardiography.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

TAPSE was assessed from the transthoracic apical window using M-mode (M-TAPSE) and the mid-esophageal 4-chamber view (2D-TAPSE). To assess 2D-TAPSE, the authors placed an annotation arrow at the junction of the tricuspid annulus and right ventricular free wall during diastole, and a second arrow at this junction at end-systole; 2D-TAPSE represented the distance between the arrows. The mean M-TAPSE was 20.5 (5.9) mm and 2D-TAPSE was 20.5 (5.8) mm. The mean angle between the direction of the lateral tricuspid annular motion and the M-mode scan line from the transthoracic apical window was 19.4 (7.6) degrees and from the mid-esophageal 4-chamber view 62.6 (15.7) degrees (p<0.001). There was a close correlation between M-TAPSE and 2D-TAPSE; r² = 0.93. Ninety-five percent of 2D-TAPSE were -3.2mm to+3.1mm of M-TAPSE (95% confidence interval -4.0 mm to+4.0 mm). The positive predictive value of 2D-TAPSE<17 mm to predict M-TAPSE<17 was 83%. The negative predictive value of 2D-TAPSE≥17 mm to predict M-TAPSE≥17 was 93%. The intra- and inter-observer variability for 2D-TAPSE was 6.7% and 9.7%, respectively.

CONCLUSIONS

Transesophageal 2D-TAPSE appeared to be a reliable and simple method to assess right ventricular function, and demonstrated a close correlation with transthoracic M-TAPSE.

Pre-chemotherapy values for left and right ventricular volumes and ejection fraction by gated tomographic radionuclide angiography using a cadmium-zinc-telluride detector gamma camera

BACKGROUND

Estimation of left ventricular ejection fraction (LVEF) using equilibrium radionuclide angiography is an established method for assessment of left ventricular function. The purpose of this study was to establish normative data on left and right ventricular volumes and ejection fraction, using cadmium-zinc-telluride SPECT camera.

METHODS AND RESULTS

From routine assessments of left ventricular function in 1172 patients, we included 463 subjects (194 men and 269 women) without diabetes, previous potentially cardiotoxic chemotherapy, known cardiovascular or pulmonary disease. The lower limits defined as mean value minus two standard deviations for ventricular ejection fraction and end diastolic volume were LVEF (men: 50%, women: 50%), LEDV (men: 45 mL, women: 40 mL), RVEF (men: 29%, women: 28%), and REDV (men: 73 mL, women: 57 mL).There was a significant negative correlation between age and both left and right ventricular volumes in women (r = -0.4, P < .001) but only for right end systolic ventricular volume in men (r = -0.3, P = .001).

CONCLUSION

A set of reference values for cardiac evaluation prior to chemotherapy in cancer patients without other known cardiopulmonary disease is presented. There are age-related changes in cardiac dimensions with age depending on gender, although with only limited influence on LVEF or RVEF.

Relationship between echocardiographic and cardiac magnetic resonance imaging-derived measures of right ventricular function in patients with chronic thromboembolic pulmonary hypertension

BACKGROUND

Echocardiography is widely used to evaluate right ventricular (RV) function. However, the value of echocardiographic parameters to assess RV function in patients with chronic thromboembolic pulmonary hypertension (CTEPH) is unknown. In this study, we analyzed the correlations between echocardiographic parameters and the RV ejection fraction (RVEF) as measured by cardiac magnetic resonance (CMR) imaging to systematically elucidate the role of echocardiographic parameters in the assessment of RV function in patients with CTEPH.

METHODS

Echocardiography was used to measure the tissue Doppler-derived tricuspid lateral annular systolic velocity (S'), fractional area change (FAC), myocardial performance index (MPI), and tricuspid annular plane systolic excursion (TAPSE). CMR was used to measure the RV end-diastolic volume (RVEDV) and end-systolic volume (RVESV), and the RVEF was calculated.

RESULTS

A significant positive correlation was found between S' and RVEF (r=0.689, P<0.0001) and between FAC and RVEF (r=0.423, P=0.022), a significant negative correlation was found between MPI and RVEF (r=-0.387, P=0.048), and no correlation was found between TAPSE and RVEF (r=0.451, P=0.22).

CONCLUSION

Echocardiography can be routinely used in the clinical setting to measure S', FAC, and MPI for the evaluation of right heart function in patients with CTEPH.

Early and six-month assessment of bi-ventricular functions following surgical closure of atrial septal defect

BACKGROUND

The effect of surgical closure of atrial septal defect (ASD) on biventricular functions is not well studied. We studied effect of surgical closure of ASD on bi-ventricular functions.

METHODS

Patients undergoing surgical closure of ASD from December 2007 to June 2009 had 3 sequential echocardiograms examination: pre-procedure, post surgery at 1-month and at 6-month of follow up. Pulse Doppler velocities across mitral and tricuspid valves were measured as peak early diastolic (E wave) and peak late diastolic (A wave). Tissue Doppler velocities across lateral wall of both right ventricle (RV) and left ventricle (LV) were measured as peak early diastolic (E'), peak late diastolic (A'), and peak systolic (S') wave. Radionuclide angiography was performed to assess RV and LV ejection fraction at baseline and at 1-month follow up.

RESULTS

The mean age of 20 enrolled patients was 21.85 ± 10.9 years; 8 females & 12 males. Trans-tricuspid flow velocities significantly decreased following surgery at one and 6-month (p < 0.005). There was no significant change in trans-mitral flow velocities at one and 6-months. Tricuspid and mitral E/A ratio and E/E' ratio also had an insignificant change following surgery. There was no significant change in LV ejection fraction as assessed by echocardiography (p = 0.132) and radionuclide scan (p = 0.143). Right ventricular ejection fraction had a significant improvement at 1-month of follow up (p = 0.005).

CONCLUSIONS

There was a significant improvement in RV systolic function and an insignificant change in RV and LV diastolic functions following surgical closure of ASD.