© 2014, Wiley Periodicals, Inc. DOI: 10.1111/echo.12212
Echocardiography
IMAGING THE RIGHT HEART
Imaging of the Right Heart—CT and CMR Jonathan Kochav, B.A.,*‡ Lauren Simprini, M.D.,† and Jonathan W. Weinsaft, M.D.†‡ *Duke University School of Medicine, Durham, North Carolina; †Memorial Sloan Kettering Cancer Center, New York, New York; and ‡Weill Cornell Medical College, New York, New York
Right ventricular (RV) structure and function is of substantial importance in a broad variety of clinical conditions. Cardiac magnetic resonance (CMR) and computed tomography (CT) each provide threedimensional RV imaging, high-resolution evaluation of RV structure/anatomy, and accurate functional assessment without geometric assumptions. This is of particular significance for the RV, where complex geometry compromises reliance on indices derived from two-dimensional (2D) imaging planes. CMR flow-based imaging can be applied to right-sided heart valves, enabling evaluation of hemodynamic and valvular dysfunction that may contribute to or result from RV dysfunction. Tissue characterization imaging by both CMR and CT provides valuable complementary assessment of the RV. Changes in myocardial tissue composition provide a mechanistic substrate for RV dysfunction and cardiac arrhythmias. This review provides an overview of RV imaging by both CMR and CT, with focus on assessment of RV structure/function, flow, and tissue characterization. Emerging evidence and established guidelines are discussed in the context of imaging contributions to diagnosis, prognostic risk stratification and disease management of clinical conditions that impact the right ventricle. (Echocardiography 2015;32:53–68) Key words: CT, CMR, right ventricle
Right ventricular (RV) structure and function is of substantial importance in a broad variety of clinical conditions. Cardiac magnetic resonance (CMR) and computed tomography (CT) each provide three-dimensional RV imaging, high-resolution evaluation of RV structure/anatomy, and accurate functional assessment without geometric assumptions. This is of particular significance for the RV, where complex geometry compromises reliance on indices derived from 2D imaging planes (Fig. 1). CMR flow-based imaging can be applied to right-sided heart valves, enabling evaluation of hemodynamic and valvular dysfunction that may contribute to or result from RV dysfunction (Table I). Tissue characterization imaging by both CMR and CT provide valuable complementary assessment of the RV. Changes in myocardial tissue composition provide a mechanistic substrate for RV dysfunction and cardiac arrhythmias. This review provides an overview of RV imaging by both CMR and CT, with focus on assessment of RV structure/function, flow, and tissue Sources of Funding: K23 HL 102249-01 (to JWW). Address for correspondence and reprint requests: Jonathan W. Weinsaft, M.D., Associate Professor of Medicine / Medicine in Radiology, Weill Cornell Medical College, 525 East 68th Street, NY, NY 10021. Fax: 212-746-8451; E-mail: [email protected]
characterization. Imaging approaches are discussed with focus on 3 general conditions for which RV assessment is of substantial clinical importance—arrhythmogenic right ventricular cardiomyopathy, congenital heart disease, and pulmonary arterial hypertension. Emerging evidence and established guidelines are discussed in the context of imaging contributions to diagnosis, prognostic risk stratification and disease management of multiple conditions that impact RV performance. Structure/Function: Imaging Approach: Cine-CMR enables assessment of both RV structure and function. Steady-state free precession (SSFP) is the pulse sequence that is most commonly used for this purpose. SSFP provides excellent endocardial cavity definition, with quality independent of body habitus or imaging plane. Using conventional breath-hold imaging, each cine image requires patient breath holding for 6– 12 seconds. Techniques such as parallel imaging and navigator gating can be employed to reduce or eliminate breath-hold times. CT can also provide comprehensive RV evaluation. RV anatomy can be assessed using prospective electrocardiographic (ECG) gating techniques, whereby radiation dose is reduced 53
Kochav, Simprini and Weinsaft
Figure 1. Utility of computed tomography (CT) and cardiac magnetic resonance (CMR) for right ventricular assessment. Right ventricular geometry produces multiple imaging challenges that can be well addressed with tomographic imaging as provided by CT and CMR.
TABLE I Relative Strengths of Imaging Modalities for the Right Ventricle
Imaging Factors RV Function Ejection fraction Regional contractility Three-dimensional volumes RV morphology Valvular flow Tissue characterization (i.e. fibrosis, fat) Pulmonary arterial pressures Clinical factors Portability Patient access/monitoring Rapidity Noncontrast Radiation exposure
CMR
CT
ECHO
+++ +++ +++ +++ ++ +++
++ ++ +++ +++ – ++
+ + + + +++ –
–
–
+++
– + ++ ++ +++
– ++ +++ + –
+++ +++ ++ +++ +++
CT = Computed Tomography
through data acquisition during a limited component of the cardiac cycle. RV functional assessment by CT requires retrospective ECG gating, which entails increased radiation exposure but provides dynamic cine images throughout the cardiac cycle. Both cine-CT and cine-CMR can quantify RV chamber volumes and ejection fraction (EF) (Fig. 2). RV quantification by both modalities has been shown to yield good reproducibility.1,2 Regional wall motion can be assessed qualitatively or quantitatively, with the latter performed on CMR using dedicated methods such as “tagging.”3–5 RV mass (calculated as total myocardial volume multiplied by specific gravity) can also be quantified. Neither CMR nor CT relies on mathematical or geometric assumptions. CMR and CT 54
normative references have been reported in several cohorts (Table II).6–9 Slight differences in normative cutoffs may reflect clinical and or methodological differences between studies. As is the case for the left ventricle, anthropomorphic indices may impact RV size, emphasizing the importance of indexation for body size and/or gender. CMR has increasingly been used as a reference standard for cardiac chamber geometry and function as it provides high reproducibility, excellent endocardial definition, and high temporal resolution. Improved reproducibility yielded by CMR (as compared with echocardiography) was demonstrated in a comparative study by Grothues et al.10 Among 60 patients undergoing sequential imaging, cine-CMR yielded smaller interstudy differences than did echo for both LV end-diastolic volumes (cine-CMR D = 0.1 3.5 mL/m2, coefficient of variation = 3.7%∣echo D = 0.6 6.7 mL/m2, coefficient of variation = 8.7%), and EF (D = 0.1 2.1, coefficient of variation = 3.7%∣D = 0.3 6.1, coefficient of variation = 11.5%). Cine-CMR has also been shown to yield excellent reproducibility for RV end-diastolic volume (D = 0.9 4.7 mL/m2, coefficient of variation 6.2%) and RVEF (D = 0.1 4.9%, coefficient of variation 8.3%).1 Particular advantages of cine-CMR that may account for its high reproducibility concern excellent endocardial definition11 and absence of limitation by extra-cardiac structures obscuring visualization of the RV chamber. Like cine-CMR, CT also enables comprehensive multiplanar imaging of the RV. However, typical temporal resolution for current generation CT scanners (~165 msec)12 is lower than that of cine-CMR (30–50 msec).13 Although it is possible that CT technical advances will improve temporal resolution,14 radiation exposure associated with CT limits application of this modality for serial assessment of the RV. Clinical Application: CMR and CT derived quantitative indices have been applied in a broad variety of settings. RV dysfunction and/or chamber remodeling has been shown to predict clinical outcomes in both population-based cohorts as well as a variety of disease-specific conditions. In the Multi-Ethnic Study of Atherosclerosis (MESA), RV hypertrophy by CMR was independently associated with a greater than 2-fold increased risk of heart failure or death (hazard ratio = 2.52; 95% confidence interval = 1.55–4.10; P < 0.001) in 4144 subjects without clinically evident cardiovascular disease.15 Among patients with established cardiovascular disease and ST-segment elevation myocardial infarction (MI), several studies have
Imaging of the Right Heart—CT and CMR
Figure 2. Right ventricular quantification. Typical example of right ventricular (RV) quantification as performed using electrocardiographic (ECG)-gated cine- computed tomography (CT). Representative images displayed in short axis from base (left) through apex (right). Volumetric planimetry of end-diastolic (top) and end-systolic (bottom) frames enables quantification of RV volumes and RV ejection fraction [(end-diastolic volume end-systolic volume) 9 100/end-diastolic volume].
shown CMR-quantified RVEF to stratify longitudinal mortality risk.16,17 The remainder of this section focuses on specific clinical conditions for which RV anatomy and function are particular clinical relevance: Arrhythmogenic right ventricular cardiomyopathy: Arrhythmogenic RV Cardiomyopathy (ARVC), a genetically mediated condition associated with myocardial fibro-fatty myocardial infiltration, confers increased risk for ventricular tachyarrhythmias and sudden cardiac death. Consensus Task Force guidelines include CMRderived indices as diagnostic criteria for ARVC.18 In addition to regional systolic dysfunction on cine-CMR, guidelines include specific CMR cutoffs for both RVEF and end-diastolic volume as both major and minor criteria (Table III). CT can be useful to evaluate known or suspected ARVC in cases where CMR is unavailable or contraindicated, such as in patients with pacemakers or implantable cardioverter-defibrillators. Bomma et al.19 demonstrated the utility of CT for ARVC, showing that RV chamber volume (224 49 vs. 163 30 mL, P < 0.01) was higher, and both RV trabeculation (100% vs. 21%, P < 0.001) and scalloping (76% vs. 7%, P < 0.001) more prevalent, among patients with, as compared to those without, ARVC. However, comparative studies have demonstrated that CMR and CT can yield differences for both RVEF (D = 1.1%, limits of agreement 8.4%) and RV end-diastolic volume (D = 4.2 mL, limits of agreement 14.6 mL), 2 parameters included as consensus criteria for ARVC.20 Accordingly, it is important to recognize that quantitative cutoffs
for ARVC as cited in consensus guidelines pertain to CMR-derived values and may not be fully applicable to CT-derived measurements. Congenital heart disease: RV functional and structural quantification is important for a broad variety of congenital conditions. In patients with surgically repaired tetralogy of Fallot (rTOF) and severe pulmonic regurgitation, consensus American College of Cardiology/American Heart Association (ACC/AHA) guidelines state that RV dilation and/or dysfunction can be used as an indication for valve replacement.21 Although these guidelines do not specify exact cutoffs for intervention, several studies utilizing CMR have reported volumetric thresholds (i.e. RV end-diastolic volume 150–170 mL/m2) at which pulmonary valve replacement resulted in normalization of RV size.22–26 Other studies have shown preoperative RV end-systolic volume and EF to predict postoperative RV function and volume,27,28 emphasizing the importance of RV quantitative indices in guiding valve replacement for patients with rTOF-associated pulmonic regurgitation. CMR indices have been linked to prognostic outcomes in patients with congenital heart disease. For example, among 88 patients with rTOF, Knauth et al.29 reported that RV end-diastolic volume (odds ratio = 4.55, 95% confidence interval 1.10–18.8, P = 0.037) and left ventricular EF (odds ratio = 8.05, 95% confidence interval 2.14–30.2, P = 0.002) independently predicted a combined clinical endpoint of death, sustained ventricular tachycardia, and increase in New York Heart Association (NYHA) class. When 55
Kochav, Simprini and Weinsaft
TABLE II Population-Based Right Ventricular Normative Values Cardiac Magnetic Resonance
Tandri et al.6 (n = 500) RV end-diastolic volume mL mL/m2 RV end-systolic volume mL mL/m2 RVEF (%) Maceira et al.7 n = (120) RV end-diastolic volume mL mL/m2 RV end-systolic volume mL mL/m2 RV ejection fraction (%) Hudsmith et al.8 n = (108) RV end-diastolic volume mL mL/m2 RV end-systolic volume mL mL/m2 RV ejection fraction (%) Computed Tomography Lin et al.9 n = 103 RV end-diastolic volume mL mL/m2 RV end-systolic volume mL mL/m2 RV ejection fraction (%)
Men
Women
Mean SD (95% CI)
Mean SD (95% CI)
142.4 31.1 (96.0,201) 82 16.2 (56.7,100.9)
110.2 24.0 (77,155) 68.6 14.0 (48.7,94.5)
54.3 16.9 (28.0,85) 31.2 9.2 (16.5,48.3) 62 1 (50,75)
35.1 12.5 (18,57) 21.7 7.5 (10.4,34) 69 1 (58,81)
163 25 (113,213) 83 12 (60,106)
126 21 (84,168) 73 9 (55,92)
57 15 (27,86) 29 7 (14,43) 66 6 (53,78)
43 13 (17,69) 25 7 (12,38) 66 6 (54,78)
190 33 (124,256) 96 15 (66,126)
148 35 (78,218) 84 17 (50,118)
78 20 (38,118) 39 10 (19,59) 59 6 (47,71)
56 18 (20,92) 32 10 (12,52) 63 5 (53,73)
174.9 48.0 (80.8,269.0) 93.3 20.3 (53.5,133.1) 82.1 29.2 (24.9,139.3) – 57.9 8.0 (42.2,73.6)
Selected from literature review of population-based normative cohorts comprising 100 patients. RV = Right ventricular.
analysis was restricted to RV indices, this study found that RVEF (odds ratio = 5.6, 95% confidence interval 1.47–21.2, P = 0.011) and RV end-diastolic volume (odds ratio = 4.00, 95% confidence interval 1.10–14.6, P = 0.036) independently predicted adverse outcomes. CT can also be employed to assess patients with congenital heart disease. For example, among patients with rTOF or D-transposition of the great arteries (D-TGA) (n = 14), Raman et al.30 demonstrated that CT and CMR yielded comparable RV volumes and EF, without systematic bias between modalities. CT can be particularly useful for postoperative patients with metallic prostheses that produce image artifacts on CMR. On the other hand, CT-associated radiation and contrast requirements may limit serial 56
imaging as can be necessary for patients with congenital heart disease. Pulmonary arterial hypertension: Pulmonary arterial hypertension (PAH), as can result from a variety of mechanisms, is a condition in which increased afterload can alter RV structure and function. Flattening of the interventricular septum can occur with PAH (Fig. 3), and has been shown to correlate with magnitude of pulmonary artery (PA) and RV systolic pressure elevation in several CMR studies.31,32 RV hypertrophy also provides a marker of disease severity.33–36 Among a cohort of 233 consecutive treatment naive patients with PAH, Swift et al.34 reported that ventricular mass index (right/left ventricular mass) was the CMR parameter that provided
Regional RV akinesia, dyskinesia, or aneurysm
And one of the following (enddiastole): Right ventricular enddiastolic volume (RVEDV/BSA) 110 mL/m2 male 100 mL/m2 female 100–
Echocardiography
IMAGING THE RIGHT HEART
Imaging of the Right Heart—CT and CMR Jonathan Kochav, B.A.,*‡ Lauren Simprini, M.D.,† and Jonathan W. Weinsaft, M.D.†‡ *Duke University School of Medicine, Durham, North Carolina; †Memorial Sloan Kettering Cancer Center, New York, New York; and ‡Weill Cornell Medical College, New York, New York
Right ventricular (RV) structure and function is of substantial importance in a broad variety of clinical conditions. Cardiac magnetic resonance (CMR) and computed tomography (CT) each provide threedimensional RV imaging, high-resolution evaluation of RV structure/anatomy, and accurate functional assessment without geometric assumptions. This is of particular significance for the RV, where complex geometry compromises reliance on indices derived from two-dimensional (2D) imaging planes. CMR flow-based imaging can be applied to right-sided heart valves, enabling evaluation of hemodynamic and valvular dysfunction that may contribute to or result from RV dysfunction. Tissue characterization imaging by both CMR and CT provides valuable complementary assessment of the RV. Changes in myocardial tissue composition provide a mechanistic substrate for RV dysfunction and cardiac arrhythmias. This review provides an overview of RV imaging by both CMR and CT, with focus on assessment of RV structure/function, flow, and tissue characterization. Emerging evidence and established guidelines are discussed in the context of imaging contributions to diagnosis, prognostic risk stratification and disease management of clinical conditions that impact the right ventricle. (Echocardiography 2015;32:53–68) Key words: CT, CMR, right ventricle
Right ventricular (RV) structure and function is of substantial importance in a broad variety of clinical conditions. Cardiac magnetic resonance (CMR) and computed tomography (CT) each provide three-dimensional RV imaging, high-resolution evaluation of RV structure/anatomy, and accurate functional assessment without geometric assumptions. This is of particular significance for the RV, where complex geometry compromises reliance on indices derived from 2D imaging planes (Fig. 1). CMR flow-based imaging can be applied to right-sided heart valves, enabling evaluation of hemodynamic and valvular dysfunction that may contribute to or result from RV dysfunction (Table I). Tissue characterization imaging by both CMR and CT provide valuable complementary assessment of the RV. Changes in myocardial tissue composition provide a mechanistic substrate for RV dysfunction and cardiac arrhythmias. This review provides an overview of RV imaging by both CMR and CT, with focus on assessment of RV structure/function, flow, and tissue Sources of Funding: K23 HL 102249-01 (to JWW). Address for correspondence and reprint requests: Jonathan W. Weinsaft, M.D., Associate Professor of Medicine / Medicine in Radiology, Weill Cornell Medical College, 525 East 68th Street, NY, NY 10021. Fax: 212-746-8451; E-mail: [email protected]
characterization. Imaging approaches are discussed with focus on 3 general conditions for which RV assessment is of substantial clinical importance—arrhythmogenic right ventricular cardiomyopathy, congenital heart disease, and pulmonary arterial hypertension. Emerging evidence and established guidelines are discussed in the context of imaging contributions to diagnosis, prognostic risk stratification and disease management of multiple conditions that impact RV performance. Structure/Function: Imaging Approach: Cine-CMR enables assessment of both RV structure and function. Steady-state free precession (SSFP) is the pulse sequence that is most commonly used for this purpose. SSFP provides excellent endocardial cavity definition, with quality independent of body habitus or imaging plane. Using conventional breath-hold imaging, each cine image requires patient breath holding for 6– 12 seconds. Techniques such as parallel imaging and navigator gating can be employed to reduce or eliminate breath-hold times. CT can also provide comprehensive RV evaluation. RV anatomy can be assessed using prospective electrocardiographic (ECG) gating techniques, whereby radiation dose is reduced 53
Kochav, Simprini and Weinsaft
Figure 1. Utility of computed tomography (CT) and cardiac magnetic resonance (CMR) for right ventricular assessment. Right ventricular geometry produces multiple imaging challenges that can be well addressed with tomographic imaging as provided by CT and CMR.
TABLE I Relative Strengths of Imaging Modalities for the Right Ventricle
Imaging Factors RV Function Ejection fraction Regional contractility Three-dimensional volumes RV morphology Valvular flow Tissue characterization (i.e. fibrosis, fat) Pulmonary arterial pressures Clinical factors Portability Patient access/monitoring Rapidity Noncontrast Radiation exposure
CMR
CT
ECHO
+++ +++ +++ +++ ++ +++
++ ++ +++ +++ – ++
+ + + + +++ –
–
–
+++
– + ++ ++ +++
– ++ +++ + –
+++ +++ ++ +++ +++
CT = Computed Tomography
through data acquisition during a limited component of the cardiac cycle. RV functional assessment by CT requires retrospective ECG gating, which entails increased radiation exposure but provides dynamic cine images throughout the cardiac cycle. Both cine-CT and cine-CMR can quantify RV chamber volumes and ejection fraction (EF) (Fig. 2). RV quantification by both modalities has been shown to yield good reproducibility.1,2 Regional wall motion can be assessed qualitatively or quantitatively, with the latter performed on CMR using dedicated methods such as “tagging.”3–5 RV mass (calculated as total myocardial volume multiplied by specific gravity) can also be quantified. Neither CMR nor CT relies on mathematical or geometric assumptions. CMR and CT 54
normative references have been reported in several cohorts (Table II).6–9 Slight differences in normative cutoffs may reflect clinical and or methodological differences between studies. As is the case for the left ventricle, anthropomorphic indices may impact RV size, emphasizing the importance of indexation for body size and/or gender. CMR has increasingly been used as a reference standard for cardiac chamber geometry and function as it provides high reproducibility, excellent endocardial definition, and high temporal resolution. Improved reproducibility yielded by CMR (as compared with echocardiography) was demonstrated in a comparative study by Grothues et al.10 Among 60 patients undergoing sequential imaging, cine-CMR yielded smaller interstudy differences than did echo for both LV end-diastolic volumes (cine-CMR D = 0.1 3.5 mL/m2, coefficient of variation = 3.7%∣echo D = 0.6 6.7 mL/m2, coefficient of variation = 8.7%), and EF (D = 0.1 2.1, coefficient of variation = 3.7%∣D = 0.3 6.1, coefficient of variation = 11.5%). Cine-CMR has also been shown to yield excellent reproducibility for RV end-diastolic volume (D = 0.9 4.7 mL/m2, coefficient of variation 6.2%) and RVEF (D = 0.1 4.9%, coefficient of variation 8.3%).1 Particular advantages of cine-CMR that may account for its high reproducibility concern excellent endocardial definition11 and absence of limitation by extra-cardiac structures obscuring visualization of the RV chamber. Like cine-CMR, CT also enables comprehensive multiplanar imaging of the RV. However, typical temporal resolution for current generation CT scanners (~165 msec)12 is lower than that of cine-CMR (30–50 msec).13 Although it is possible that CT technical advances will improve temporal resolution,14 radiation exposure associated with CT limits application of this modality for serial assessment of the RV. Clinical Application: CMR and CT derived quantitative indices have been applied in a broad variety of settings. RV dysfunction and/or chamber remodeling has been shown to predict clinical outcomes in both population-based cohorts as well as a variety of disease-specific conditions. In the Multi-Ethnic Study of Atherosclerosis (MESA), RV hypertrophy by CMR was independently associated with a greater than 2-fold increased risk of heart failure or death (hazard ratio = 2.52; 95% confidence interval = 1.55–4.10; P < 0.001) in 4144 subjects without clinically evident cardiovascular disease.15 Among patients with established cardiovascular disease and ST-segment elevation myocardial infarction (MI), several studies have
Imaging of the Right Heart—CT and CMR
Figure 2. Right ventricular quantification. Typical example of right ventricular (RV) quantification as performed using electrocardiographic (ECG)-gated cine- computed tomography (CT). Representative images displayed in short axis from base (left) through apex (right). Volumetric planimetry of end-diastolic (top) and end-systolic (bottom) frames enables quantification of RV volumes and RV ejection fraction [(end-diastolic volume end-systolic volume) 9 100/end-diastolic volume].
shown CMR-quantified RVEF to stratify longitudinal mortality risk.16,17 The remainder of this section focuses on specific clinical conditions for which RV anatomy and function are particular clinical relevance: Arrhythmogenic right ventricular cardiomyopathy: Arrhythmogenic RV Cardiomyopathy (ARVC), a genetically mediated condition associated with myocardial fibro-fatty myocardial infiltration, confers increased risk for ventricular tachyarrhythmias and sudden cardiac death. Consensus Task Force guidelines include CMRderived indices as diagnostic criteria for ARVC.18 In addition to regional systolic dysfunction on cine-CMR, guidelines include specific CMR cutoffs for both RVEF and end-diastolic volume as both major and minor criteria (Table III). CT can be useful to evaluate known or suspected ARVC in cases where CMR is unavailable or contraindicated, such as in patients with pacemakers or implantable cardioverter-defibrillators. Bomma et al.19 demonstrated the utility of CT for ARVC, showing that RV chamber volume (224 49 vs. 163 30 mL, P < 0.01) was higher, and both RV trabeculation (100% vs. 21%, P < 0.001) and scalloping (76% vs. 7%, P < 0.001) more prevalent, among patients with, as compared to those without, ARVC. However, comparative studies have demonstrated that CMR and CT can yield differences for both RVEF (D = 1.1%, limits of agreement 8.4%) and RV end-diastolic volume (D = 4.2 mL, limits of agreement 14.6 mL), 2 parameters included as consensus criteria for ARVC.20 Accordingly, it is important to recognize that quantitative cutoffs
for ARVC as cited in consensus guidelines pertain to CMR-derived values and may not be fully applicable to CT-derived measurements. Congenital heart disease: RV functional and structural quantification is important for a broad variety of congenital conditions. In patients with surgically repaired tetralogy of Fallot (rTOF) and severe pulmonic regurgitation, consensus American College of Cardiology/American Heart Association (ACC/AHA) guidelines state that RV dilation and/or dysfunction can be used as an indication for valve replacement.21 Although these guidelines do not specify exact cutoffs for intervention, several studies utilizing CMR have reported volumetric thresholds (i.e. RV end-diastolic volume 150–170 mL/m2) at which pulmonary valve replacement resulted in normalization of RV size.22–26 Other studies have shown preoperative RV end-systolic volume and EF to predict postoperative RV function and volume,27,28 emphasizing the importance of RV quantitative indices in guiding valve replacement for patients with rTOF-associated pulmonic regurgitation. CMR indices have been linked to prognostic outcomes in patients with congenital heart disease. For example, among 88 patients with rTOF, Knauth et al.29 reported that RV end-diastolic volume (odds ratio = 4.55, 95% confidence interval 1.10–18.8, P = 0.037) and left ventricular EF (odds ratio = 8.05, 95% confidence interval 2.14–30.2, P = 0.002) independently predicted a combined clinical endpoint of death, sustained ventricular tachycardia, and increase in New York Heart Association (NYHA) class. When 55
Kochav, Simprini and Weinsaft
TABLE II Population-Based Right Ventricular Normative Values Cardiac Magnetic Resonance
Tandri et al.6 (n = 500) RV end-diastolic volume mL mL/m2 RV end-systolic volume mL mL/m2 RVEF (%) Maceira et al.7 n = (120) RV end-diastolic volume mL mL/m2 RV end-systolic volume mL mL/m2 RV ejection fraction (%) Hudsmith et al.8 n = (108) RV end-diastolic volume mL mL/m2 RV end-systolic volume mL mL/m2 RV ejection fraction (%) Computed Tomography Lin et al.9 n = 103 RV end-diastolic volume mL mL/m2 RV end-systolic volume mL mL/m2 RV ejection fraction (%)
Men
Women
Mean SD (95% CI)
Mean SD (95% CI)
142.4 31.1 (96.0,201) 82 16.2 (56.7,100.9)
110.2 24.0 (77,155) 68.6 14.0 (48.7,94.5)
54.3 16.9 (28.0,85) 31.2 9.2 (16.5,48.3) 62 1 (50,75)
35.1 12.5 (18,57) 21.7 7.5 (10.4,34) 69 1 (58,81)
163 25 (113,213) 83 12 (60,106)
126 21 (84,168) 73 9 (55,92)
57 15 (27,86) 29 7 (14,43) 66 6 (53,78)
43 13 (17,69) 25 7 (12,38) 66 6 (54,78)
190 33 (124,256) 96 15 (66,126)
148 35 (78,218) 84 17 (50,118)
78 20 (38,118) 39 10 (19,59) 59 6 (47,71)
56 18 (20,92) 32 10 (12,52) 63 5 (53,73)
174.9 48.0 (80.8,269.0) 93.3 20.3 (53.5,133.1) 82.1 29.2 (24.9,139.3) – 57.9 8.0 (42.2,73.6)
Selected from literature review of population-based normative cohorts comprising 100 patients. RV = Right ventricular.
analysis was restricted to RV indices, this study found that RVEF (odds ratio = 5.6, 95% confidence interval 1.47–21.2, P = 0.011) and RV end-diastolic volume (odds ratio = 4.00, 95% confidence interval 1.10–14.6, P = 0.036) independently predicted adverse outcomes. CT can also be employed to assess patients with congenital heart disease. For example, among patients with rTOF or D-transposition of the great arteries (D-TGA) (n = 14), Raman et al.30 demonstrated that CT and CMR yielded comparable RV volumes and EF, without systematic bias between modalities. CT can be particularly useful for postoperative patients with metallic prostheses that produce image artifacts on CMR. On the other hand, CT-associated radiation and contrast requirements may limit serial 56
imaging as can be necessary for patients with congenital heart disease. Pulmonary arterial hypertension: Pulmonary arterial hypertension (PAH), as can result from a variety of mechanisms, is a condition in which increased afterload can alter RV structure and function. Flattening of the interventricular septum can occur with PAH (Fig. 3), and has been shown to correlate with magnitude of pulmonary artery (PA) and RV systolic pressure elevation in several CMR studies.31,32 RV hypertrophy also provides a marker of disease severity.33–36 Among a cohort of 233 consecutive treatment naive patients with PAH, Swift et al.34 reported that ventricular mass index (right/left ventricular mass) was the CMR parameter that provided
Regional RV akinesia, dyskinesia, or aneurysm
And one of the following (enddiastole): Right ventricular enddiastolic volume (RVEDV/BSA) 110 mL/m2 male 100 mL/m2 female 100–
