doc w/ Pen

journalist + medical student + artist

Tag: cardiology

The anatomy of a heart, and a water bottle

As I explained in my last post, medical descriptions are sometimes a little … strange. Some of them, as I learned yesterday, are also generation-dependent.

I was sitting at my desk after a long day in the hospital, studying for my medicine shelf exam (aka final exam). While doing cardiology review questions on my laptop, I came across a scenario in which a woman had a pericardial effusion. Essentially, this is a collection of fluid surrounding the heart. The chest x-ray was described as showing a “‘water bottle’ heart shape.”

Below is an image I found online that’s similar to the one from my practice question. Think about your conception of a water bottle, then look at the image.

This is the chest x-ray of a patient with a pericardial effusion.

Staring at my laptop screen, I thought to myself, “This doesn’t look like any water bottle I’ve ever seen.” I tried to think creatively, how one might fit a Fiji, Evian, or Aquafina bottle into that globular shape. Try as I might, I failed.

So I Google-image-searched this phrase: “pericardial effusion water bottle silhouette.” Most of the images that came up looked just like the one above. That didn’t help me. But when I found this image on Radiopaedia, an online collection of radiology cases, (see below) the analogy suddenly made sense. Whoever first compared the heart silhouette in a pericardial effusion to a water bottle probably never saw a plastic, disposable water bottle, like the ones we use today. His (and it was most likely a “he” since most doctors were men back then) conception of a water bottle was very different from mine. As Radiopaedia explains, “The fluid-filled pericardial sac casts a cardiac silhouette that resembles an old-fashioned leather water bottle.”

The “water bottle-shaped heart” in pericardial effusion explained, with a visual aid. From

I initially felt satisfied with my investigation, but the journalist in me cried out for confirmation from a second source. So I went back to Google images, digging a little deeper. And I found these:

This interpretation of “water bottle” was quite different. I don’t really consider these glass bottles “water bottles” in the same way I do both the plastic bottles of today and the old-fashioned leather bottle in the Radiopaedia image. But then again, what do I know? Maybe around the time x-rays were first being used clinically, in the late 1890s, the vessels above were considered “water bottles.” I’m a little skeptical of this, but the image with the greenish x-ray and the clear glass bottle comes from a well-respected medical journal, BMJ Heart. So it’s hard to discount this comparison completely.

To try and come up with a little more information, I Googled the same phrase “pericardial effusion water bottle silhouette” to look at text results too. The seventh result was a 2016 article from an international emergency medicine journal. The article is called “Message in a bottle: The use of chest radiography for diagnosis of pericardial effusion.” I didn’t read the entire article (I was studying for a test, remember?) but I did skim it, looking for “water bottle” references. The whole article is about using the “water bottle sign” to clue you into the presence of a pericardial effusion, and to help you decide whether to perform advanced imaging. The article actually refers to the water bottle sign 12 times. But not once does the article explain how this image looks like a water bottle, only that it does.

I am still studying for my test (I’ve got 48 hours left to master the field of internal medicine). So I must stop my descent into the rabbit hole of this question. Perhaps someone, somewhere in the world, still uses a water bottle that resembles the globe-shaped heart seen in a pericardial effusion x-ray. Perhaps that person would understand this arcane medical reference. But for the most part, at least to those of us in medicine who are using this reference today, it is outdated. It lives on, though, because as much as medicine is about progress, it is also about history.

I Heart Ultrasound

apical view

This is an apical four-chamber view of the heart via ultrasound. Key: RV = right ventricle; TV = tricuspid valve; RA = right atrium; LV = left ventricle; AV = aortic valve; MV = mitral valve; LA = left atrium. Image from

Even though the focus of the first year of medical school is book-learning, we’re gradually acquiring hands-on skills like taking medical histories and performing a basic physical exam. This week, we got to try something different—cardiac ultrasound. Increasingly used for bedside diagnosis, ultrasound is seen by the Weill Cornell administration as an essential part of our education. It’s also pretty darn cool.

This past Tuesday afternoon, we broke into small groups and rotated through practice exam rooms where we met up with different faculty members and standardized patients. Each group member got a chance to obtain different views of the heart with the ultrasound transducer, including the parasternal long axis, parasternal short axis, apical four chamber, and subxiphoid views.

It was incredible to see the live heart in action, the muscle pumping and the valves fluttering before our eyes, after studying the organ in such great depth for four weeks. The machine we used was pretty nifty too. The screen was not much larger than an iPad. It was mounted standing up, with the ultrasound transducer attached via a cable. Knowing where to put the transducer on the patient’s chest wasn’t so hard—the difficult part was making incremental adjustments to center the image or angle the transducer to better see the chambers or valves. Like everything worthwhile, getting a quality ultrasound image will take practice. But this was a good start.

When it comes to what we’re learning, I like the science. I really do. But it’s clinical activities like this one that remind me of why I’m truly here.