Catheterization and Cardiovascular Diagnosis 2:125-136 (19761
Original Studies
RIGHT VENTRICULAR MASS ESTIMATION B Y ANGIOECHOCARDIOGRAPHY Rene A. Arcilla, M.D., Rajamma Mathew, M.B.B.S., M.R.C.P. (Edin.), Peter Sodt, Lucille Lester, M.D., Noel Cahill, M.D., and Otto G. Thilenius, M.D., Ph.D. A combined angiocardiographic-echocardiographicmethod for estimating right ventricular wall mass is described. Biplane cineangiocardiograms are analyzed for ventricular volume in end-diastole, and wall thickness is determined from echocardiograms obtained with a high frequency transducer and strip chart recorder. The intracavitary and the external surface volumes of the ventricle are derived, and the difference multiplied by 1.050, the specific gravity of myocardium. Excellentcorrelation was observed between right ventricular wall mass and body surface area in normal children (r = 0.93). The mean right ventricular mass was 44.5 g/MZas compared to 78.1 g/Mz for the left ventricle; corresponding mass/EDV values were 0.48 g/cm3and 1.26 g/cm3,respectively. In isolated right ventricular pressureoverload, the increase in right ventricular mass is chiefly due to the increase in wail thickness; in volume overload, it is due mostly to the increase in chamber volume.
Key words: right ventricle, mass, wail thickness, ventricular volume, echocardiography, angiocardiography
Evaluation of cardiac performance by angiocardiography usually includes the determination of left ventricular end-diastolic and end-systolic volumes. stroke volume. ejection fraction. and mass. Volume estimation is conventionally by the area-length method of Dodge (1). and ventricular mass by the method of Rackley et al. (2) which takes into consideration the difference between the intracavitary and external surface volumes. With the exception of right ventricular mass estimation. right heart performance has been evaluated similarly utilizing different angiographic methods (3-6). Most of these have been carried out in children. From the Cardiology Sectlon, Department of Pediatrics, The University of Chicago Pritzker School of Medicine, Chicago, Illinois.
Reprint requests to: Dr. Rene A . Arcilla. Department of Pediatrics. Wyler Children’s Hospital. University of Chicago, 950 East 59th Street, Chicago. lllinois 60637 Received September I . 1975. revision accepted February 17. 1976
125
0 1 9 7 6 Alan R. Liss, Inc., 150 Fifth Avenue, New York, N.Y. 10011
126
Arcilla et al.
The purpose of this communication is to describe a method for estimating right ventricular mass utilizing a combined angiocardiographic-echocardiographicapand also proach. It is based on the same principle used for the left ventricle (3, involves calculating the external surface volume and the intracavitary volume by a technique previously reported (3). Data on right ventricular mass in children with normal and abnormal hearts are presented. MATERIALS AND METHODS Experimental Model Casts were made of the right ventricle and left ventricle of 35 freshly obtained mini pig or dog hearts. These were prepared by injecting liquid, room temperature. vulcanizing silicone rubber (RTV-I 1 . General Electric Co.). mixed with barium sulfate to render it radiopaque, into both ventricles. This plastic material provided better reproduction of the cardiac anatomy than the Nu-gel-barium mixture utilized in a previous study (3). At the time of sacrifice, 35%.potassium chloride solution was injected into the circulation until cardiac standstill appeared. The heart was removed immediately. Both atrial walls and the atrial septum were resected approximately 0.5-1 cm above the atrioventricular groove. The remaining atrial tissue was used to oversew the tricuspid and mitral valves. Both ventricles were filled retrogradely with the cast material under low filling pressures of 5-10 mm Hg. The heart with its casts was then suspended over a Philips 5-in biplane cineangiographic unit and was positioned in a manner as to simulate as closely as possible the orientation of the human heart in vivo. Biplane radiographs were obtained in the frontal and lateral projections. The casts were then removed and their volumes determined by fluid (benzalkonium chloride solution) displacement. Frontal and lateral plane radiographs were again obtained of each cast positioned similarly. The tricuspid valve and the atrial cuff were removed. The free wall of the right ventricle was resected along the ventricular septum and then weighed. This represented right ventricular wall mass. The mitral valve and left atrial cuff were also removed from the left ventricle. The left ventricle, including the entire ventricular septum, was then weighed. This represented left ventricular mass. The radiologic images of the casts were traced on paper and their areas in the frontal plane (A3 and in the lateral plane (A3 obtained by planimetry (HewlettPackard Calculator-Digitizer, Model 9107 A). The maximal apex-base axis (LmaJof the right ventricle was measured from the lateral image, and that of the left ventricle from the frontal image. All measurements were corrected for X-ray magnification, and all volume calculations were by the parallelepiped method (3). The basic equation for volume was: Vi(e)
-
Af A,
(See Appendix I).
L a x
The initial volume estimate Vi(e)was corrected by a regression equation specific for the right ventricle or left ventricle: (for left ventricle) Vi(c)= 0.77 Vi(e)+ 1.17; (for right ventricle) Vi(=)= 0.65 Vi(e) 0.01; where Vitc) = intracavitary corrected volume. These correcting regression equations were derived from a plot of Vi(e)vs. the true cast volume, Vi(t)(Fig. 1).
+
Right Ventricular Mass Estimation
LEFT VENTRICLE
RIGHT VENTRICLE
1
r = 0.984 p
Original Studies
RIGHT VENTRICULAR MASS ESTIMATION B Y ANGIOECHOCARDIOGRAPHY Rene A. Arcilla, M.D., Rajamma Mathew, M.B.B.S., M.R.C.P. (Edin.), Peter Sodt, Lucille Lester, M.D., Noel Cahill, M.D., and Otto G. Thilenius, M.D., Ph.D. A combined angiocardiographic-echocardiographicmethod for estimating right ventricular wall mass is described. Biplane cineangiocardiograms are analyzed for ventricular volume in end-diastole, and wall thickness is determined from echocardiograms obtained with a high frequency transducer and strip chart recorder. The intracavitary and the external surface volumes of the ventricle are derived, and the difference multiplied by 1.050, the specific gravity of myocardium. Excellentcorrelation was observed between right ventricular wall mass and body surface area in normal children (r = 0.93). The mean right ventricular mass was 44.5 g/MZas compared to 78.1 g/Mz for the left ventricle; corresponding mass/EDV values were 0.48 g/cm3and 1.26 g/cm3,respectively. In isolated right ventricular pressureoverload, the increase in right ventricular mass is chiefly due to the increase in wail thickness; in volume overload, it is due mostly to the increase in chamber volume.
Key words: right ventricle, mass, wail thickness, ventricular volume, echocardiography, angiocardiography
Evaluation of cardiac performance by angiocardiography usually includes the determination of left ventricular end-diastolic and end-systolic volumes. stroke volume. ejection fraction. and mass. Volume estimation is conventionally by the area-length method of Dodge (1). and ventricular mass by the method of Rackley et al. (2) which takes into consideration the difference between the intracavitary and external surface volumes. With the exception of right ventricular mass estimation. right heart performance has been evaluated similarly utilizing different angiographic methods (3-6). Most of these have been carried out in children. From the Cardiology Sectlon, Department of Pediatrics, The University of Chicago Pritzker School of Medicine, Chicago, Illinois.
Reprint requests to: Dr. Rene A . Arcilla. Department of Pediatrics. Wyler Children’s Hospital. University of Chicago, 950 East 59th Street, Chicago. lllinois 60637 Received September I . 1975. revision accepted February 17. 1976
125
0 1 9 7 6 Alan R. Liss, Inc., 150 Fifth Avenue, New York, N.Y. 10011
126
Arcilla et al.
The purpose of this communication is to describe a method for estimating right ventricular mass utilizing a combined angiocardiographic-echocardiographicapand also proach. It is based on the same principle used for the left ventricle (3, involves calculating the external surface volume and the intracavitary volume by a technique previously reported (3). Data on right ventricular mass in children with normal and abnormal hearts are presented. MATERIALS AND METHODS Experimental Model Casts were made of the right ventricle and left ventricle of 35 freshly obtained mini pig or dog hearts. These were prepared by injecting liquid, room temperature. vulcanizing silicone rubber (RTV-I 1 . General Electric Co.). mixed with barium sulfate to render it radiopaque, into both ventricles. This plastic material provided better reproduction of the cardiac anatomy than the Nu-gel-barium mixture utilized in a previous study (3). At the time of sacrifice, 35%.potassium chloride solution was injected into the circulation until cardiac standstill appeared. The heart was removed immediately. Both atrial walls and the atrial septum were resected approximately 0.5-1 cm above the atrioventricular groove. The remaining atrial tissue was used to oversew the tricuspid and mitral valves. Both ventricles were filled retrogradely with the cast material under low filling pressures of 5-10 mm Hg. The heart with its casts was then suspended over a Philips 5-in biplane cineangiographic unit and was positioned in a manner as to simulate as closely as possible the orientation of the human heart in vivo. Biplane radiographs were obtained in the frontal and lateral projections. The casts were then removed and their volumes determined by fluid (benzalkonium chloride solution) displacement. Frontal and lateral plane radiographs were again obtained of each cast positioned similarly. The tricuspid valve and the atrial cuff were removed. The free wall of the right ventricle was resected along the ventricular septum and then weighed. This represented right ventricular wall mass. The mitral valve and left atrial cuff were also removed from the left ventricle. The left ventricle, including the entire ventricular septum, was then weighed. This represented left ventricular mass. The radiologic images of the casts were traced on paper and their areas in the frontal plane (A3 and in the lateral plane (A3 obtained by planimetry (HewlettPackard Calculator-Digitizer, Model 9107 A). The maximal apex-base axis (LmaJof the right ventricle was measured from the lateral image, and that of the left ventricle from the frontal image. All measurements were corrected for X-ray magnification, and all volume calculations were by the parallelepiped method (3). The basic equation for volume was: Vi(e)
-
Af A,
(See Appendix I).
L a x
The initial volume estimate Vi(e)was corrected by a regression equation specific for the right ventricle or left ventricle: (for left ventricle) Vi(c)= 0.77 Vi(e)+ 1.17; (for right ventricle) Vi(=)= 0.65 Vi(e) 0.01; where Vitc) = intracavitary corrected volume. These correcting regression equations were derived from a plot of Vi(e)vs. the true cast volume, Vi(t)(Fig. 1).
+
Right Ventricular Mass Estimation
LEFT VENTRICLE
RIGHT VENTRICLE
1
r = 0.984 p
