© 2014, Wiley Periodicals, Inc. DOI: 10.1111/echo.12611
Echocardiography
Atrial Mechanics after Surgical Repair of Tetralogy of Fallot Jia Hou, M.D., Hong-kui Yu, M.D., Sophia J. Wong, B.Sc., and Yiu-fai Cheung, M.D. Division of Paediatric Cardiology, Department of Pediatrics and Adolescent Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong, China
Background: Ventricular diastolic dysfunction in patients with repaired tetralogy of Fallot (TOF) may affect atrial mechanics. This study aimed to explore right atrial (RA) and left atrial (LA) mechanics in repaired TOF patients and their relationship with ventricular diastolic function. Methods: Fifty-four patients (36 males), aged 17.8 8.3 years, who had undergone TOF repair at 3.9 3.3 years and 40 healthy subjects aged 16.9 6.3 years (P = 0.57) were studied. Right and LA peak positive, peak negative, and total strain, strain rate at ventricular systole (SRs), early diastole (SRed), and atrial contraction (SRac), and electromechanical delay were determined using speckle tracking echocardiography (STE). Ventricular diastolic function was assessed by tissue Doppler imaging and STE. Ventricular volumes and pulmonary regurgitant volume were derived from 3D echocardiography. Results: Compared with controls, patients had significantly lower RA and LA peak positive and total strain, SRs, SRed, and SRac (all P < 0.001). The timing of RA (178 33 msec vs. 152 17 msec, P < 0.001) and LA (170 32 msec vs. 152 24 msec, P = 0.006) electromechanical coupling (EMC) was significantly longer in patients than in controls. The RA total strain, SRs, SRed, SRac, and EMC correlated positively with corresponding LA parameters (all P < 0.001). The RA and LA total strain and SRed were associated positively with diastolic annular velocities and strain rates of respective ventricles (all P < 0.05). The LA SRed correlated negatively with pulmonary regurgitant volume (r = 0.33, P = 0.016) and RV end-diastolic volume (r = 0.33, P = 0.015). Conclusion: Mechanics of both atria are impaired in patients after repair of TOF and are associated with diastolic performance of the respective ventricles. (Echocardiography 2015;32:126–134) Key words: tetralogy of Fallot, atrial strain, speckle tracking echocardiography Long-term cardiac sequelae after repair of tetralogy of Fallot (TOF) include chronic pulmonary regurgitation, right ventricular (RV) volume overload, cardiac arrhythmias, and RV and left ventricular (LV) dysfunction.1 Ventricular dysfunction has further been shown to predict adverse outcomes late after TOF repair.2,3 Optimal cardiac performance depends, however, not only on normal functioning of the ventricles but also the atria. Previous studies in repaired TOF have nonetheless focused on assessment of ventricular mechanics and ventricular–ventricular interaction with limited attention to atrial function.4–6 Jia Hou is a research fellow from Cardiovascular Center, Children’s Hospital of Fudan University, Shanghai, China and Hong-kui is a research fellow from Shenzhen Children’s Hospital, Guangdong, China Address for correspondence and reprint requests: Yiu-fai Cheung, M.D., Division of Paediatric Cardiology, Department of Paediatrics and Adolescent Medicine, Queen Mary Hospital, The University of Hong Kong, 102, Pokfulam Road, Hong Kong, China. Fax: 852-25539491; E-mail: [email protected]
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The atria transform continuous venous return into intermittent ventricular filling. They act as a reservoir during ventricular systole, a conduit during opening of the atrioventricular valve in early ventricular diastole, and a pump during late ventricular diastole.7,8 The pump function of the atria depends in turn on electrical activation and electromechanical coupling (EMC).8 The clinical relevance of atrial function is increasingly recognized. Altered left atrial (LA) function has been shown to occur with aging9 and found in patients with atrial fibrillation,10 LV dysfunction,11,12 and hypertension.13 Furthermore, LA enlargement has been demonstrated to predict adverse cardiovascular outcomes in patients with congestive heart failure, stroke, transient ischemic attack, and myocardial infarction.14 In repaired TOF, the reported ventricular diastolic dysfunction6,15 may affect atrial mechanics. Understanding of atrial function and atrioventricular interaction in repaired TOF patients has, however, been limited. Advances in echocardiographic imaging technology have enabled noninvasive evaluation of
Atrial Mechanics in Repaired TOF
atrial function.8 Two-dimensional speckle tracking echocardiography (STE) is increasingly used to assess LA16 and right atrial (RA)17 function given its relative angle independence and ability to assess global atrial mechanics. In the present study, we aimed to explore using STE to assess the atrial mechanics in repaired TOF patients and their relationship with ventricular diastolic function. Methods: Subjects: Fifty-four patients with repaired TOF were studied. The following data were retrieved from the case records: age at operation, types of surgical procedure, and duration of follow-up as TOF repair. Forty healthy subjects, including those assessed for nonspecific chest pain and palpitation but without documented cardiac arrhythmias and organic causes, healthy siblings of patients, and adult staff volunteers were recruited as controls. The body weight and height of all subjects were measured and the body surface area was calculated accordingly. The Institutional Review Board approved the study and all subjects gave informed consent. Two-Dimensional and Doppler Echocardiography: Transthoracic echocardiography was performed using Vivid 7 ultrasound machine (General Electric, Vingmed, Horten, Norway). The frame rate of two-dimensional (2D) image acquisition was set to at least between 60 and 80 frames/sec. Offline analyses of the echocardiographic recordings were performed using EchoPAC software (General Electric). Measurements were made in three cardiac cycles and the average was used for statistical analyses. From the apical four-chamber view, the maximum LA and RA areas were measured just before the opening of the atrioventricular valve in end-systole by planimetry. Pulsed-wave Doppler examination was performed to determine the transatrioventricular peak early (E) and late (A) diastolic velocities, transmitral E deceleration time, and E/A ratio. Pulsed tissue Doppler imaging was performed from the apical four-chamber view for measurement of mitral and tricuspid annular peak early (e) and late (a) diastolic myocardial tissue velocities, and the respective E/e ratios. Speckle Tracking Echocardiography: Two-dimensional images acquired from the apical four-chamber view were used for analyses of global atrial mechanics and ventricular diastolic deformation using the commercial software
(EchoPAC, General Electric). To determine global atrial deformation, the entire endocardial contour of RA and LA was traced and tracked by the software (Fig. 1). The onset of the P-wave was used as the reference point for determination of the following parameters of global atrial deformation: peak positive strain, peak negative strain, total strain, and strain rate at ventricular systole (SRs), early diastole (SRed), and atrial contraction (SRac).8,16 EMC of the right and left atria was evaluated by measuring the time from the onset of P-wave to, respectively, the peak negative RA and LA strain.8 Right and left ventricular global longitudinal diastolic strain rates were assessed from the four-chamber view, while LV circumferential and radial diastolic strain rates were determined from the mid-parasternal shortaxis view as described previously.18,19 We have previously reported a high reproducibility of ventricular strain measurements by STE.18–20 Three-Dimensional Echocardiography: Real time 3D echocardiographic imaging was performed from the apical view using a matrix-array transducer. The RV and LV datasets were acquired separately to ensure the inclusion of the entire ventricular chamber. Full-volume acquisition with capturing of 4 adjacent subvolumes over 4 consecutive cardiac cycles was performed during breathhold. For quantitative RV analysis, 3 slices at orthogonal planes (sagittal, coronal, and fourchamber planes) based on the 3D dataset were displayed for tracing of RV endocardial border at end-diastole and end-systole with a semiautomated detection process. For quantitative LV analysis, the endocardial border in each of the 3 slices (2-, 3-, and 4-chamber planes) at end-systole and end-diastole was traced. Offline analyses were performed using commercial 4D LV and RV analysis software (Tomtec Imaging Systems, Unterschleisheim, Germany). Based on the RV and LV casts created, ventricular end-diastolic and end-systolic volumes and ejection fraction were derived. A high reproducibility of measuring RV and LV ejection fraction using 3D echocardiography-derived volumes has also been reported previously by our group.4 The pulmonary regurgitant volume in TOF patients was estimated by the difference between RV and LV stroke volumes. Statistical Analysis: Data are expressed as mean SD. The atrial areas and ventricular volumes were indexed by body surface area. Absolute values of strain and strain rate were used to facilitate presentation and interpretation. Demographic and echocardiographic parameters of patients were compared with those of controls using
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Figure 1. Right and left atrial strain and strain rate curves in a patient and a control subjects ( ve = negative; +ve = positive; SRs = strain rate at ventricular systole; SRed = strain rate at early diastole; SRac = strain rate at atrial contraction). LA = left atrium; LV = left ventricle; RA = right atrium; RV = right ventricle.
unpaired Student’s t-test. Intra- and interobserver variability in measurements of atrial strain and strain rate was assessed in 20 subjects, 10 patients, and 10 controls, and reported as coefficients of variation. Relationships between atrial strain parameters and
128
indices of ventricular diastolic function and RV volume load were assessed using Pearson correlation analysis. A P value
Echocardiography
Atrial Mechanics after Surgical Repair of Tetralogy of Fallot Jia Hou, M.D., Hong-kui Yu, M.D., Sophia J. Wong, B.Sc., and Yiu-fai Cheung, M.D. Division of Paediatric Cardiology, Department of Pediatrics and Adolescent Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong, China
Background: Ventricular diastolic dysfunction in patients with repaired tetralogy of Fallot (TOF) may affect atrial mechanics. This study aimed to explore right atrial (RA) and left atrial (LA) mechanics in repaired TOF patients and their relationship with ventricular diastolic function. Methods: Fifty-four patients (36 males), aged 17.8 8.3 years, who had undergone TOF repair at 3.9 3.3 years and 40 healthy subjects aged 16.9 6.3 years (P = 0.57) were studied. Right and LA peak positive, peak negative, and total strain, strain rate at ventricular systole (SRs), early diastole (SRed), and atrial contraction (SRac), and electromechanical delay were determined using speckle tracking echocardiography (STE). Ventricular diastolic function was assessed by tissue Doppler imaging and STE. Ventricular volumes and pulmonary regurgitant volume were derived from 3D echocardiography. Results: Compared with controls, patients had significantly lower RA and LA peak positive and total strain, SRs, SRed, and SRac (all P < 0.001). The timing of RA (178 33 msec vs. 152 17 msec, P < 0.001) and LA (170 32 msec vs. 152 24 msec, P = 0.006) electromechanical coupling (EMC) was significantly longer in patients than in controls. The RA total strain, SRs, SRed, SRac, and EMC correlated positively with corresponding LA parameters (all P < 0.001). The RA and LA total strain and SRed were associated positively with diastolic annular velocities and strain rates of respective ventricles (all P < 0.05). The LA SRed correlated negatively with pulmonary regurgitant volume (r = 0.33, P = 0.016) and RV end-diastolic volume (r = 0.33, P = 0.015). Conclusion: Mechanics of both atria are impaired in patients after repair of TOF and are associated with diastolic performance of the respective ventricles. (Echocardiography 2015;32:126–134) Key words: tetralogy of Fallot, atrial strain, speckle tracking echocardiography Long-term cardiac sequelae after repair of tetralogy of Fallot (TOF) include chronic pulmonary regurgitation, right ventricular (RV) volume overload, cardiac arrhythmias, and RV and left ventricular (LV) dysfunction.1 Ventricular dysfunction has further been shown to predict adverse outcomes late after TOF repair.2,3 Optimal cardiac performance depends, however, not only on normal functioning of the ventricles but also the atria. Previous studies in repaired TOF have nonetheless focused on assessment of ventricular mechanics and ventricular–ventricular interaction with limited attention to atrial function.4–6 Jia Hou is a research fellow from Cardiovascular Center, Children’s Hospital of Fudan University, Shanghai, China and Hong-kui is a research fellow from Shenzhen Children’s Hospital, Guangdong, China Address for correspondence and reprint requests: Yiu-fai Cheung, M.D., Division of Paediatric Cardiology, Department of Paediatrics and Adolescent Medicine, Queen Mary Hospital, The University of Hong Kong, 102, Pokfulam Road, Hong Kong, China. Fax: 852-25539491; E-mail: [email protected]
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The atria transform continuous venous return into intermittent ventricular filling. They act as a reservoir during ventricular systole, a conduit during opening of the atrioventricular valve in early ventricular diastole, and a pump during late ventricular diastole.7,8 The pump function of the atria depends in turn on electrical activation and electromechanical coupling (EMC).8 The clinical relevance of atrial function is increasingly recognized. Altered left atrial (LA) function has been shown to occur with aging9 and found in patients with atrial fibrillation,10 LV dysfunction,11,12 and hypertension.13 Furthermore, LA enlargement has been demonstrated to predict adverse cardiovascular outcomes in patients with congestive heart failure, stroke, transient ischemic attack, and myocardial infarction.14 In repaired TOF, the reported ventricular diastolic dysfunction6,15 may affect atrial mechanics. Understanding of atrial function and atrioventricular interaction in repaired TOF patients has, however, been limited. Advances in echocardiographic imaging technology have enabled noninvasive evaluation of
Atrial Mechanics in Repaired TOF
atrial function.8 Two-dimensional speckle tracking echocardiography (STE) is increasingly used to assess LA16 and right atrial (RA)17 function given its relative angle independence and ability to assess global atrial mechanics. In the present study, we aimed to explore using STE to assess the atrial mechanics in repaired TOF patients and their relationship with ventricular diastolic function. Methods: Subjects: Fifty-four patients with repaired TOF were studied. The following data were retrieved from the case records: age at operation, types of surgical procedure, and duration of follow-up as TOF repair. Forty healthy subjects, including those assessed for nonspecific chest pain and palpitation but without documented cardiac arrhythmias and organic causes, healthy siblings of patients, and adult staff volunteers were recruited as controls. The body weight and height of all subjects were measured and the body surface area was calculated accordingly. The Institutional Review Board approved the study and all subjects gave informed consent. Two-Dimensional and Doppler Echocardiography: Transthoracic echocardiography was performed using Vivid 7 ultrasound machine (General Electric, Vingmed, Horten, Norway). The frame rate of two-dimensional (2D) image acquisition was set to at least between 60 and 80 frames/sec. Offline analyses of the echocardiographic recordings were performed using EchoPAC software (General Electric). Measurements were made in three cardiac cycles and the average was used for statistical analyses. From the apical four-chamber view, the maximum LA and RA areas were measured just before the opening of the atrioventricular valve in end-systole by planimetry. Pulsed-wave Doppler examination was performed to determine the transatrioventricular peak early (E) and late (A) diastolic velocities, transmitral E deceleration time, and E/A ratio. Pulsed tissue Doppler imaging was performed from the apical four-chamber view for measurement of mitral and tricuspid annular peak early (e) and late (a) diastolic myocardial tissue velocities, and the respective E/e ratios. Speckle Tracking Echocardiography: Two-dimensional images acquired from the apical four-chamber view were used for analyses of global atrial mechanics and ventricular diastolic deformation using the commercial software
(EchoPAC, General Electric). To determine global atrial deformation, the entire endocardial contour of RA and LA was traced and tracked by the software (Fig. 1). The onset of the P-wave was used as the reference point for determination of the following parameters of global atrial deformation: peak positive strain, peak negative strain, total strain, and strain rate at ventricular systole (SRs), early diastole (SRed), and atrial contraction (SRac).8,16 EMC of the right and left atria was evaluated by measuring the time from the onset of P-wave to, respectively, the peak negative RA and LA strain.8 Right and left ventricular global longitudinal diastolic strain rates were assessed from the four-chamber view, while LV circumferential and radial diastolic strain rates were determined from the mid-parasternal shortaxis view as described previously.18,19 We have previously reported a high reproducibility of ventricular strain measurements by STE.18–20 Three-Dimensional Echocardiography: Real time 3D echocardiographic imaging was performed from the apical view using a matrix-array transducer. The RV and LV datasets were acquired separately to ensure the inclusion of the entire ventricular chamber. Full-volume acquisition with capturing of 4 adjacent subvolumes over 4 consecutive cardiac cycles was performed during breathhold. For quantitative RV analysis, 3 slices at orthogonal planes (sagittal, coronal, and fourchamber planes) based on the 3D dataset were displayed for tracing of RV endocardial border at end-diastole and end-systole with a semiautomated detection process. For quantitative LV analysis, the endocardial border in each of the 3 slices (2-, 3-, and 4-chamber planes) at end-systole and end-diastole was traced. Offline analyses were performed using commercial 4D LV and RV analysis software (Tomtec Imaging Systems, Unterschleisheim, Germany). Based on the RV and LV casts created, ventricular end-diastolic and end-systolic volumes and ejection fraction were derived. A high reproducibility of measuring RV and LV ejection fraction using 3D echocardiography-derived volumes has also been reported previously by our group.4 The pulmonary regurgitant volume in TOF patients was estimated by the difference between RV and LV stroke volumes. Statistical Analysis: Data are expressed as mean SD. The atrial areas and ventricular volumes were indexed by body surface area. Absolute values of strain and strain rate were used to facilitate presentation and interpretation. Demographic and echocardiographic parameters of patients were compared with those of controls using
127
Hou, et al.
Figure 1. Right and left atrial strain and strain rate curves in a patient and a control subjects ( ve = negative; +ve = positive; SRs = strain rate at ventricular systole; SRed = strain rate at early diastole; SRac = strain rate at atrial contraction). LA = left atrium; LV = left ventricle; RA = right atrium; RV = right ventricle.
unpaired Student’s t-test. Intra- and interobserver variability in measurements of atrial strain and strain rate was assessed in 20 subjects, 10 patients, and 10 controls, and reported as coefficients of variation. Relationships between atrial strain parameters and
128
indices of ventricular diastolic function and RV volume load were assessed using Pearson correlation analysis. A P value
