Picture Perfect:
Subcostal View Optimization
Pat Fontaine, one of of career emergency medicine physician assistants, at Albany Medical Center recently captured these images from a late middle aged male with a history of prior MI. The parasternal views are limited, but can you identify the abnormality on the subcostal clips? If so, where is the problem? Scroll to the bottom for an explanation!
Traditionally, the subcostal views offer only a few insights: we look for pericardial effusion at the most dependent aspect of the heart, we examine the IVC, and we look for organized activity during cardiac arrest. This case illustrates two powerful points—first, the subcostal approach can be a strong go-to in patients with poor / nonexistent transthoracic windows. This is particularly relevant in the setting of COPD and hyperinflated lungs, chest trauma, or for patients with tall, thin body habitus where the heart hangs more vertically in the chest, hiding behind anterior lung tissue. Second, if you can orient yourself to the subcostal anatomy, complex judgments such as quantification of ejection fraction, regional wall motion assessment, and RV function are all quite possible! The subcostal short axis can show us flattening or inversion of the interventricular septum in RV overload, and RV longitudinal function can be measured from the subcostal 4-chamber view. Perhaps most importantly, regional wall motion abnormalities can be observed from the subcostal short axis and used to risk stratify potential acute coronary syndrome. Use these tips to level-up your subcostal imaging:
-
Optimize the subcostal views by placing the patient supine in semi-Fowlers with knees bent to relax the abdominal muscles. Asking the patient to perform an inspiratory hold will force the heart down against the diaphragm, often dramatically improving visibility from below.
Obtain the subcostal short axis by rotating the probe 90° counter-clockwise from the traditional subcostal 4-chamber view. You can now view a subcostal basilar short axis and look directly up into the pulmonary artery, look for regional wall motion abnormalities at the level of the papillary muscles, or look at the apex if there is systolic dysfunction and concern for mural thrombi.
Make sure not to mistake the IVC for the aorta; it is easy to search satisfy on the aorta when there is a thin, practically nonexistent IVC. Use the subcostal great vessel view to move between interrogation of the IVC and a quick look for dissection in the descending aorta—that way you see both and know which is which.
When there is concern for RV dysfunction, a TAPSE can be obtained from the subcostal 4-chamber by measuring horizontal rather than vertical excursion of the tricuspid annular plane. This is what is called subcostal echocardiographic assessment of tricuspid annular kick (SEATAK)—normal is generally regarded as >13mm.
In some cases, a subcostal apical 4-chamber view can be obtained by swinging the probe toward the left flank while still beneath the ribcage.
References
(1) Flower L, Madhivathanan PR, Andorka M, Olusanya O, Roshdy A, Sanfilippo F. Getting the most from the subcostal view: The rescue window for intensivists. J Crit Care. 2021;63:202-210. doi:10.1016/j.jcrc.2020.09.003
(2) Grotberg JC, McDonald RK, Co IN. Point-of-Care Echocardiography in the Difficult-to-Image Patient in the ICU: A Narrative Review. Crit Care Explor. 2024;6(1):e1035. Published 2024 Jan 11. doi:10.1097/CCE.0000000000001035