Heartstrings are the colloquial term for chordae tendineae, which are fibrous connections anchoring the tricuspid and bicuspid valve leaflets (atrioventricular valves) to the papillary muscles of the ventricular walls (Langman’s Medical Embryology, pg 194). In normal blood flow, deoxygenated blood enters the right atrium into the right ventricle. As the right ventricle starts to fill, the increase in pressure closes the tricuspid valve, preventing regurgitation of blood. The same mechanism applies to the closing of the bicuspid valve during left ventricular filling. Now, if these fibrous chords were to rupture, tension of the AV valves would decrease and blood would flow from the ventricles to the atria and the great vessels.
Normally, treatment for regurgitation is surgical intervention, either with a repair or replacement of the valve by open-heart surgery (Honjo et al., 2011). A new AV valve repair technique includes taking a partition of the patient’s pericardium to repair the affected leaflets (Pick, n.d.). This technique was founded by a cardiothoracic surgeon in Japan, but it has been slowly adopted here in the US (Pick, n.d). The morphology of the affected valve and the mechanism of abnormal function are factors that affect patient outcome and determine reintervention in the future.
The image below is a series of Kaplan-Meier plots that show the survival rate of patients who have undergone AV valve replacement or repair. Those whose right AV valve abnormalities with normal function had a higher survival rate than those with left AV valve problems or AV valves that had poor function. This highlights the importance of risk factors such as congenital septation defects (Honjo et al., 2011). In this same study, 14% patients passed away in the hospital following an AV valve replacement/repair either due to sudden cardiac failure, or failed to thrive. This is important ethically because there is an increased risk of heart failure following surgery. There is also a risk of reintervention, but in some patients this surgical intervention will last for the rest of their lives.
So the idiom of pulling on your heartstrings may have some anatomical basis, although not accurate physiologically.
Aortic Valve Repair surgery. Heart Valve Surgery. (n.d.). Retrieved November 20, 2022, from https://www.heart-valve-surgery.com/aortic-valve-repair-surgery.php
Honjo, O., Atlin, C. R., Mertens, L., Al-Radi, O. O., Redington, A. N., Caldarone, C. A., & Van Arsdell, G. S. (2011). Atrioventricular valve repair in patients with functional single-ventricle physiology: Impact of ventricular and valve function and morphology on survival and reintervention. The Journal of Thoracic and Cardiovascular Surgery, 142(2). https://doi.org/10.1016/j.jtcvs.2010.11.060
Sadler, T. W., Leland, J., Sadler-Redmond, S. L., Tosney, K., Chescheir, N., Imseis, H., & Langman, J. (2010). Langman's medical embryology. Wolters Kluwer.
I found your intro to be very intriguing as I immediately thought of the phrase being used when you see something sad (like the ASPCA commercials). I wanted to see if there were any known environmental causes for chordae tendinae rupture (CTR). My research came up empty handed for causes such as being very sad from seeing sick puppies as the main causes for CTR are: sub-acute endocarditis, rheumatic heart disease, mitral valve prolapse, and myxomatous degeneration (Gabbay, 2010). They mentioned that all other causes were not evident (Gabbay, 2010). This means that those sad puppies will not actually lead to pulling or rupturing of those heart strings. But man does it sure feel like that when I see those commercials.
ReplyDeleteCitation:
Gabbay U, Yosefy C. The underlying causes of chordae tendinae rupture: a systematic review. Int J Cardiol. 2010 Aug 20;143(2):113-8. doi: 10.1016/j.ijcard.2010.02.011. Epub 2010 Mar 7. PMID: 20207434.