Tiny Hearts

“Tiny heart,

Stuck inside yourself

When will you open up?”

Lacey Sturm, James Culpepper, Sameer Bhattacharya, Jared Hartmann, Pat Seals, and Mark Lewis for Flyleaf, “Tiny Heart,” Momento Mori (A&M Octone Records, 2009)

This month’s issue of CASE once again brings front and center the incredible ability of echocardiography to obtain high-quality, diagnostic images of a fetal heart. As the rapidly growing heart develops, it changes from about the size of an almond (weeks 16-20), to a walnut (weeks 24-30), to a Brazil nut (weeks 30-34), eventually becoming the size of a large chestnut at full term (Figure 1). Furthermore, the heart rate averages 150 beats per minute. As an echocardiographer who primarily images adults, those findings seem almost inconceivable for quality imaging. Yet month after month, CASE is able to demonstrate the tremendous high quality that is available with current ultrasound platforms, sonographer technical skills, and physician expertise.

Figure 1.

Graphic illustration of the tiny heart that rapidly grows as the fetus develops as compared to common nuts; the center fetal echo was obtained at 22 weeks’ gestation and demonstrates a 4-chamber view with mesoposition/mild dextroposition. Central echo image reused under CC BY-NC-ND 4.0 (https://creativecommons.org/licenses/by-nc-nd/4.0/), from Tedla B, Golding F, Ryan J, Sun HY. Fetal Diagnosis of Dextroposition, Left Pulmonary Artery Sling, Partial Anomalous Left Pulmonary Artery, and Aortic Coarctation. CASE, 2022; 6, 114-118, https://doi.org/10.1016/j.case.2022.01.007.

Historically, the first images of the fetus used x-rays (early to mid-1900s), until we grew more knowledgeable regarding their harmful effects. As ultrasound was becoming the remarkable technological breakthrough we all know, the field of fetal medicine was certainly an even greater benefactor. For the first time, physicians could take the necessary time to scan the fetus without risk. All developments we are familiar with have specific and unique applications within the developing fetus. Advances in temporal resolution were necessary given the fast heart rates. The Doppler evolution provided access to a much greater understanding of venoarterial flow. A common saying (often credited to the late Dr. William J. Rashkind) in the pediatric/congenital world is that “you need flow to grow.” These advances in Doppler techniques were once again more impactful in the fetus than in the adult (Figure 2).

Figure 2.

Evolution of color-flow Doppler resolution from 1988 until now: visualization of hypoplastic left heart syndrome. (A) A case using color-flow Doppler, in 1988, and (B–D) subsequent examples from 1996 (B), 2008 (C), and 2020 (D). Reprinted with permission from Chaoui, R. (2021), Evolution of fetal cardiac imaging in 30 years of ISUOG. Ultrasound Obstet Gynecol, 57: 38-42. https://doi.org/10.1002/uog.23551, 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Today, with the use of three-dimensional (3D) echocardiography, spatiotemporal image correlation (STIC) software obtains excellent volume-rendered reconstructions of large blocks of cardiac anatomy (Figure 3).¹ Spatiotemporal image correlation can acquire approximately 150 two-dimensional (2D) images per second, creating a complete cardiac data set in 10 to 15 seconds. Additional software tools provide unique lighting perspectives that deliver photorealistic images similar to the state-of-the-art images we are familiar with seeing from adults. There is little doubt that these technologic developments will increase prenatal detection of congenital heart disease.

Figure 3.

Three-dimensional STIC reconstruction demonstrates an extracardiac tunnel arising from the ascending aorta above the aortic valve and entering the left ventricle, consistent with aortico–left ventricular tunnel. Ao, Aorta; Asc Ao, ascending aorta. Reused under CC BY-NC-ND 4.0 (https://creativecommons.org/licenses/by-nc-nd/4.0/), from Le TK, Hoang TH, Sklansky MS. Prenatal Diagnosis of Aorto–Left Ventricular Tunnel. CASE, 2026; 8: 342-345.

In this month’s issue of CASE, I am excited to summarize 8 reports that span a wide variety of cardiac pathologies and the authors’ approach to using imaging to guide their diagnosis and subsequent approach to management. This issue concludes with a couple of reports of complex congenital heart disease that were diagnosed prenatally.

In “Pacing-Induced Transient Severe Mitral Regurgitation during Transcatheter Aortic Valve Implantation,” the authors used their report to warn echocardiographers involved in transcatheter aortic valve implantation procedures to be aware of the possibility of acute, severe mitral regurgitation that is transient and self-limited. They postulate that rapid pacing may cause mitral apparatus dysfunction that resolves spontaneously during serial echocardiography. Distinguishing this reversible phenomenon from structural valve injury is important in management planning.

In “Multimodal Imaging and Management of Early Mitral Annuloplasty Ring Dehiscence with Pericardial Hematoma,” the authors used multimodal imaging to diagnose mitral annuloplasty ring dehiscence complicated by an impressive pericardial hematoma. Mitral annuloplasty ring dehiscence is a rare, life-threatening cause of recurrent mitral regurgitation, and these images are worth your look.

In “When the Prosthetic Aortic Valve Fails: An Unusual Intraoperative Finding,” the authors unveil an unsuspected cause of severe prosthetic aortic regurgitation in the immediate postbypass period. Their report highlights the role of intraoperative transesophageal echocardiography (TEE) imaging and the importance of the echocardiographer in closely monitoring the positioning of the left ventricular (LV) vent, which, when malpositioned, may be the culprit for an underrecognized cause of acute aortic regurgitation. I am happy to point out that this work was performed by my colleagues, and therefore, this report was handled by a guest editor to avoid conflict. Our sincere thanks goes out to Jan Kasal, MD, FASE.

In “The Use of Point-of-Care Transesophageal Echocardiography in the Diagnosis of Undifferentiated Cardiac Arrest in a Pregnant Patient,” the authors used point-of-care TEE to acquire focused images in a pregnant patient with undifferentiated pulseless electrical activity cardiac arrest. Their findings were instrumental in redirecting clinical management toward appropriate hemodynamic support for severe, peripartum cardiomyopathy. Their point-of-care TEE findings allowed them to avoid unnecessary perimortem cesarean section and resuscitative hysterotomy. They emphasize that the use of TEE has the potential to alter both intra-arrest and postarrest management, and its use in these clinical settings is expanding.

In “Multimodality Imaging of Gonococcal Pulmonary Valve Endocarditis,” the authors present a patient with pulmonary valve infective endocarditis due to Neisseria gonorrhoeae. Their imaging includes excellent fluorine-18 fluorodeoxyglucose positron emission tomography and computed tomography images to illustrate the active dissemination of infection. Although this is an uncommon presentation in native valves in patients without traditional right-sided risk factors, this report serves to remind us it remains possible and requires a high index of suspicion.

In “Libman-Sacks Endocarditis (LSE) as a Noninfectious Cardiac Complication of Acute Promyelocytic Leukemia in an Adolescent,” the authors highlight a pediatric patient with LSE. This report serves to reiterate that this may occur in the absence of an autoimmune disease or systemic lupus erythematosus, especially in the setting of a malignancy. Their report includes an excellent discussion on the appropriate role for anticoagulation and/or immunosuppressive therapy to prevent complications.

In “Tetralogy of Fallot and Complete Atrioventricular Septal Defect with Absent Atrial Component of the Septal Defect,” the authors present outstanding 3D images in a neonate with trisomy 21. Their findings were unusual and included tetralogy of Fallot and complete atrioventricular septal defect with absence of the atrial component of the septal defect. They discuss why this unique cardiac defect adds complexity to the diagnosis and surgical repair and the important role of 2D and 3D echo.

In “Fetal Agenesis of the Ductus Venosus with Extrahepatic Shunt,” the authors do a wonderful job of illustrating the importance of the ductus venosus (DV) in fetal development. As an important resistor in umbilical venous return, it optimizes streaming of oxygenated placental venous return to the most essential developing organs. Agenesis of the DV is rare and may result in either intrahepatic or, as in their patient, extrahepatic shunts. Their patient presented with high-output heart failure, which resolved over fetal life, further demonstrating the uniquely critical and dynamic role of the DV in early pregnancy that decreases over fetal life. If you enjoyed reading the history of fetal echo at the beginning of this editorial, you simply must finish by learning how their fetal echo was used to reliably monitor serial fetal cardiac function.

I would also like to thank Curt DeGroff, MD, who submitted a Letter to the Editor titled “Proper Usage of the Terms ‘Turbulent’ and ‘Laminar’ in Color-Flow Doppler.” This report reminds us of the importance of language precision and asks each of us to rethink our abundant and over-use of the term “turbulence” in our scientific reports.

Thanks for taking the time to read this editorial. I hope you also had a few minutes to listen to “Tiny Hearts” and possibly added a new song to your personal music collection. For the few interested readers who have started a CASE Editor’s Spotify list, I would like to point out that this editorial started as “Little Feet” (which was intended to be a play on the wonderful rock band Little Feat), but then I came across “Tiny Hearts,” which won me over.

Remember, every echo you see today has a teaching point and every teaching point is a potential new CASE report!