Cardiac catheterization is a pretty common procedure. And while much of it seems fairly straightforward on a superficial level, learning the craft is a different story.

Much like any procedure or surgery, a quick reference for refreshers on the go can be really helpful given how much learning happens by doing. And there are many concepts, like understanding intracardiac pressures, that can be useful for many clinicians outside of the cath lab.

CathSource, developed by the same folks behind EchoSource and ECGSource, is a quick reference app covering everything from procedural basics to the nuances of differentiating constrictive and restrictive cardiac disease.

On opening the app, we are taken to a home screen which identifies the authors and developers of the app as Dr. Rocky Bilhartz and Dr. Mazi Mahjoobi, both of whom are interventional cardiologists in Texas. Dr. Bilhartz also has several other apps in the app store focused on cardiology including EchoSource and ECGSource.


As we noted in our EchoSource review, a suggestion here would be to only briefly display this Home screen before taking the user automatically to the Index. Tapping over to the Index section, we are presented with a nicely organized list of topics organized into broad categories of coronaries, aorta, left ventricle, procedure, and hemodynamics. There is also a search bar at the top of the menu, though it appears that this feature is not terribly robust as it appears to only search words contained in the titles of each section.


We’ll start with the Coronary: Normal Anatomy section as an example. Each section consists of generally well written and easy to understand text going through the topic as well as a mix of illustrations, cath images, and cath videos. The videos are of high quality and can be paused or scrolled through frame by frame, making them great teaching tools as well.



The content is very practical and relevant to the practice of coronary angiography, written for someone learning rather than an experienced operator. The authors go through the basics like describing the standard views, not only showing them but explaining the “why” as well. For example, in explaining the importance of orthogonal views in identifying eccentric lesions they provide great images of a critical left main lesion missed entirely on one view but seen on another.



The information in the procedure sections is detailed and practical as well. For example, the description of radial access includes descriptions of the Allens/Barbeau tests, techniques for getting access, wire selection, and need for fluoroscopy/angiography of the arm – basically a start-to-finish description of getting radial access.



One section that would be useful to add is information on the different catheters available for diagnostic angiography.

There are great explanations of techniques like FFR, IVUS, and OCT as well as excellent descriptions of the various hemodynamic assessments that can be performed in the cath lab. I was particularly impressed with the inclusion of a technical description of how pressures are actually measured.




The content in the hemodynamics sections is well written and, again, quite practical. For example, in the constriction/restriction section there is a great overview of the pathophysiology and differential diagnosis followed by a description of what can be done in the cath lab to identify if either of these processes is present. It would be nice to have some actual pressure tracings included in the app rather than just illustrations though.




Finally, the images and videos contained in the app are also directly reviewable in the Images section which includes a search function as well. The quality of the videos in particular is excellent.





Available for iOS and Android (reviewed on iPhone 5S)

Evidence & References

Information in the app is referenced in a rather informal fashion within the text, generally citing either peer-reviewed papers or text books. There is information that is not clearly referenced and it can be difficult to tell at times what was specifically sourced versus what is based on the experience of the authors. In the case of the latter, authorship is important and it is worth reminding ourselves that the authors are interventional cardiologists.


  • Well written content that is detailed and practical
  • Excellent use of illustrations, images, and video
  • Simple and clean user interface


  • Lack of information on diagnostic catheters
  • Lack of links to references as well as informal referencing structure


  • CathSource contains a wealth of well written, practical, and detailed information on cardiac catheterization that is well organized and makes appropriate use of illustrations, images, and video. It is an excellent resource for anyone learning about cardiac catheterization and its use in the evaluation of a wide range of cardiac diseases.


Disclaimer: This post does not establish, nor is it intended to establish, a patient physician relationship with anyone. It does not substitute for professional advice, and does not substitute for an in-person evaluation with your healthcare provider. It does not provide the definitive statement on the subject addressed. Before using these apps please consult with your own physician or healthcare provider.