Abstract
A 25-year-old woman with a recent diagnosis of congenital heart disease and probable endocarditis was referred to our institution. During our evaluation we observed an unusual deformation of both ventricles. We discuss its possible origin as revealed by printing of a three-dimensional model. (Level of Difficulty: Advanced.)
Key Words: computed tomography, congenital heart defect, papillary muscles, three-dimensional printing
Abbreviations and Acronyms: CMR, cardiac magnetic resonance; CT, computed tomography
Central Illustration
History of Presentation
A 25-year-old woman was referred for treatment at our institution with a recent diagnosis of pulmonary valvar disease and probable endocarditis. Over the past 3 months she had experienced progressive dyspnea, consistent with New York Heart Association functional class III heart failure, and a prolonged fever. On examination, systolic pulsations were palpable in the left parasternal area. Auscultation revealed the first heart sound to be normal, with a decrease in the pulmonary component of the second heart sound. A third heart sound was audible in the left parasternal fourth intercostal space, along with a midsystolic ejection murmur at the middle to upper left sternal border. A decrescendo diastolic murmur was heard in the second and third left intercostal spaces, which increased in intensity during inspiration and decreased during the Valsalva maneuver. During our evaluation of the imaging studies, we observed a finding in the ventricular walls that, to the best of our knowledge, is unique. Although we are sure that the finding was not the cause of the symptoms, nor of the findings at physical examination, the images are so unusual that we believe they are deserving of comment.
Learning Objectives
-
•
To describe a unique case of deformation of the ventricular cone, produced by failed formation of papillary muscles.
-
•
To show evidence in favor of remodeling of excessive trabeculation.
-
•
To recognize the usefulness of 3D printing in the study of complex cases.
Medical History
The patient had no additional significant medical history, had no cardiovascular risk factors, and did not describe episodes of either chest pain, edema, arrhythmia, or syncope.
Differential Diagnosis
Inasmuch as we have been unable to find comparable cases, we are unable to suggest a differential diagnosis for the rare finding in our patient.
Investigations
CT demonstrated valvar and subvalvar pulmonary stenosis, with the images compatible with the presence of a vegetation in the pulmonary trunk. The trunk and its branches were dilated, and the oval foramen was patent. The remarkable finding revealed by the images was the deformation at the level of the middle third of both ventricles. The images also showed that the left ventricular papillary muscles were not grouped in the anticipated fashion. Instead, they were located at the basal third of the ventricular cone, which also showed markedly excessive trabeculation (Figures 1A to 1E). The right ventricle was dilated, with hypertrophied walls interpreted as being secondary to the valvar disease. As in the left ventricle, we also observed deformation of its walls at the level of the papillary muscles (Figures 1A to 1C, Video 1).
Figure 1.
Electrocardiographic-Gated Multiplanar Computed Tomography Angiography (Retrospective Protocol)
Computed tomography showing a remarkable deformation in the walls of the ventricles (curved white arrows), abnormal grouping of papillary muscles (black arrows), and excessive trabeculation (red asterisk). (A) 4-chamber view. (B) 3-chamber view. (C) Right heart chambers and outflow tract, subvalvar pulmonary stenosis is also observed (D) 2-chamber view. (E) Level of the deformation in the short axis, confirming the abnormal arrangement of the papillary muscles. (F) Volumetric reconstruction. Ao = aorta; LA = left atrium; LV = left ventricle; PA = pulmonary artery; PT = pulmonary trunk; RA = right atrium; RV = right ventricle.
The 2-dimensional images were confirmed by the volumetric reconstruction (Figure 1F). Owing to the rarity of the findings, we decided to make a 3-dimensional printed model. The printer used was 3D Professional Industrial Creality Cr-5 Pro, and the material of the model was PLA BASIC 1.75-mm filament (Figure 2, Supplemental File). This confirmed the extent of the equatorial constriction of both ventricles, permitting us also to demonstrate the findings as would be seen in the frontal view of a chest radiograph. Despite the abnormal findings, however, the global, segmental mobility, and systolic functions were all normal, and there was no obstruction in the left ventricular outflow tract. Additional investigation with magnetic resonance imaging (Figure 3), ruled out any myocardial ischemia or infarction. No intraventricular gradients were found (Videos 2 and 3).
Figure 2.
3-Dimensional Printing Model
(A) Frontal view, in the chest X-ray, the notable deformation cannot be observed, however, when superimposing the 3D model, the deformation is shown on the lower wall of the right ventricle (RV) (curved arrow). (B) View of the base of the heart showing that the constriction (curved arrow) is marked in both ventricles, giving the appearance of 4 ventricles. (C) View from above showing deformation and stenosis at the infundibular level (asterisk). (D) View of the lateral wall of the left ventricle (LV) showing the oblique path of the deformation. ICV = inferior caval vein; LAA = left atrial appendage; RAA = right atrial appendage; RPA = right branch of pulmonary trunk; RCA = dominant right coronary artery; SCV = superior caval vein; other abbreviations as in Figure 1.
Figure 3.
Cardiac Magnetic Resonance and Computed Tomography
(A) True fast imaging with steady-state free precession sequence showing accumulation of fatty tissue (asterisk) outside the ventricular walls, at the level of the deformation, more evident in the left ventricle (LV). (B) Steady-state free precession sequence of 2 chambers showing the deformation of the wall around the LV and the accumulation of fatty tissue (asterisk) at this level. (C) Computed tomography view modified for the right ventricle (RV), showing the constriction of the walls of both ventricles (arrows). Abbreviations as in Figure 1.
Management
Inasmuch the investigations indicated that the abnormal findings in the ventricular walls did not produce any hemodynamic alteration, we confined ourselves to treating the right ventricular problems. The patient underwent placement of a pulmonary valve prosthesis, enlargement of the right ventricular outflow tract, infundibulectomy, resection of the vegetation, and closure of the patent oval foramen.
Discussion
We suggest that this deformation was produced by incomplete formation of the papillary muscles, with this process “pinching” the ventricular cone. It is significant that the constriction was found at the junction between the ventricular inlets and the apical components. There was also evidence of excessive trabeculation. The images show that the compact layer was very well formed but that the trabeculations had themselves also compacted. We suggest that this implies abnormal remodeling of the trabecular layer, which normally would form only the papillary muscles. Supporting our interpretation is the presence of an anomalous muscle bundle in the right ventricle. There was no evidence to support the notion that the trabeculations coalesce to form the compact ventricular walls. However, it is becoming increasingly evident that they do compact to form the papillary muscles.1,2 We suggest that this process had gone astray in our patient, producing an equatorial constriction of the ventricular cone. However, we found no evidence that this anatomical constriction produced any alteration in the ventricular function.
Follow-Up
Three years after the surgical treatment of the right-sided problems, the patient had reported no cardiovascular symptoms. Repeated magnetic resonance imaging revealed dysfunction of the pulmonary prosthesis, albeit without any evidence of abnormal hemodynamic behavior at the level of the deformation.
Conclusions
We report the previously undescribed finding of equatorial constriction of both ventricles, in the absence of any alteration in ventricular function.
Funding Support and Author Disclosures
The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
Footnotes
The authors attest they are in compliance with human studies committees and animal welfare regulations of the authors’ institutions and Food and Drug Administration guidelines, including patient consent where appropriate. For more information, visit the Author Center.
Appendix
For supplemental file and videos, please see the online version of this paper.
Appendix
ECG-Gated Multiplanar Computed Tomography. Under retrospective protocol, 4-chamber view showing the right ventricle and the inferoseptal and anterolateral walls of the left ventricle with adequate mobility and thickening.
Cardiac Magnetic Resonance. Cine sequence showing the left ventricular outflow tract without anatomical or functional obstruction, A deformation is observed in the inferolateral wall; however, mobility is normal.
Cardiac Magnetic Resonance. TRUFI sequence: cross section from mediastinum to diaphragm.
References
- 1.Jensen B., Christoffels V.M., Moorman A.F.M. An appreciation of anatomy in the molecular world. J Cardiovasc Dev Dis. 2020;7:44. doi: 10.3390/jcdd7040044. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Pumacayo-Cárdenas S.C., Arias-Vela G., Quea-Pinto E. 3-Dimensional impression of a rare congenital disease of aortic and supra-aortic vessels. Rev Colomb Cardiol. 2020;27:122–126. [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
ECG-Gated Multiplanar Computed Tomography. Under retrospective protocol, 4-chamber view showing the right ventricle and the inferoseptal and anterolateral walls of the left ventricle with adequate mobility and thickening.
Cardiac Magnetic Resonance. Cine sequence showing the left ventricular outflow tract without anatomical or functional obstruction, A deformation is observed in the inferolateral wall; however, mobility is normal.
Cardiac Magnetic Resonance. TRUFI sequence: cross section from mediastinum to diaphragm.