This is a compilation of the notes that I made while preparing for my MS General Surgery final exams. They were written using the Notability app on the iPad. They were intended to be my personal revision aid, nothing more. Because they weren’t created for the purpose of distribution, no attempts have been made to reference them. For the sake of convenience, they have been organised under broad headings.
While preparing these notes I’ve referred to the following-
1. Bailey and Love’s Short Practice of Surgery- 27th edition
2. Sabiston Textbook of Surgery- 20th edition
3. Schwartz’s Principles of Surgery- 11th edition
4. Maingot’s Abdominal Operations -13th edition
5. Fischer’s Mastery of Surgery – 7th edition
6. Shackelford’s Surgery of the Alimentary Tract- 8th edition
7. DeVita, Hellman and Rosenberg’s Cancer- 11th edition
8. MD Anderson Handbook of Surgical Oncology- 6th edition
9. Campbell Walsh Wein Urology 12th edition
10. Stone’s Plastic Surgery Facts 4th edition
11. Plastic Surgery Secrets Plus 2nd edition
12. Grabb and Smith’s Plastic Surgery 7th edition
13. Pediatric Surgery Digest
14. Ashcraft’s Pediatric Surgery 6th edition
15. Rutherford’s Vascular Surgery 8th edition
Medscape and UpToDate have also been very useful. The supplementary materials offered by MAMC, New Delhi as a part of their annual Surgery Update programme are a fine source of review material as well and have been utilised in the preparation of these notes.
These notes also contain material imbibed during classes, case discussions and subject seminars at the Department of General Surgery and other allied specialties at Mysore Medical College and Research Institute.
I offer no guarantees regarding the accuracy of the content of these notes. Nor do I make any claims at creating anything exceptional. nāpūrvamastīha vikārahīnam (Yogavāsiṣṭham 1.27.33)
I am sharing them here in the hope that someone might find them useful.
(03.08.2020, Śrī Hayagrīva Jayantī)
Mitral Valve Prolapse (MVP) has several names.A few are descriptive and self-explanatory: billowing mitral leaflet syndrome, floppy valve syndrome and systolic click-murmur syndrome. It has one particularly unhelpful name as well- Barlow syndrome.
It’s a no-brainer that MVP causes Mitral Regurgitation (MR). MVP is, in fact, described as a primary mitral regurgitation resulting from myxomatous degeneration of the unfortunate valve. Other important causes of MR are rheumatic heart disease, ischemic heart disease (leading to papillary muscle dysfunction) and dilated cardiomyopathy, to name a few.
MVP holds special interest for us because it is a lesion with a difference!
Let’s refresh our memories: The classic MR murmur is pansystolic, best heard with the patient’s breath held in expiration, accentuated by hand grip/ squatting/ phenylephrine (things that lead to an increase in the systemic vascular resistance) and decreased on strain/valsalva (things that ultimately decrease the systemic vascular resistance).
MVP begs to differ.
It produces a late systolic murmur with an occasional ‘honking’ or ‘whooping’ quality, often associated with one or more mid to late systolic clicks. Interestingly, it is louder and starts earlier with breath held in inspiration. It is louder on strain/ valsalva and diminishes with hand grip.
Why this difference?
This question naturally prods us to explore the mechanism behind the murmurs. Lets take a look..
Mitral regurgitation produces a systolic regurgitant murmur. The murmur is because of the turbulent flow across the incompetent mitral valve which does not shut completely when the left ventricle is in systole.
When the left ventricle contracts, blood is squeezed out through TWO channels–> 1. The aorta 2. The incompetent mitral valve.
It should be obvious that anything which increases the turbulent flow across the incompetent mitral valve should make the regurgitant murmur louder..
When does this happen?
a) Whenever the volume of blood in the left ventricle increases
b) Whenever blood is preferentially squeezed across the incompetent valve
When does the volume of the left ventricle increase? During expiration. Why? During expiration, the pressure within the thorax increases. This pressure squeezes both air and BLOOD out of the lungs. Where does all that blood go? It goes to the left atrium via the pulmonary veins. Next stop- Left ventricle! When the left ventricle goes into systole, there is more blood to be pumped out and so, more turbulent flow across the mitral valve. This creates a louder murmur.
When will blood prefer to gush across the incompetent mitral valve? When the aorta resists it! And when does that happen? When the systemic vascular resistance increases… When a lion’s share of the blood in the left ventricle gushes into the left atrium during LV systole, what happens to the murmur? It roars louder!
MR- changes with expiration and increased systemic vascular resistance
Now, why should the murmur in Mitral Valve Prolapse behave any differently?
What is different?
Wait for it………
In most other causes of MR, it is the BLOOD which makes the noise! The murmur is produced when blood gurgles past the helpless mitral valve.
But in MVP, it is mainly the VALVES which make the noise!! The valves are rendered floppy and loose by myxomatous degeneration. When the left ventricle squeezes out blood, the jet makes the valve leaflets flutter and prolapse into the left atrium with a whoosh…
When will the whoosh be louder? When the leaflets are allowed to flutter free..
This leads us to yet another question: What holds the valve apparatus in place? It is time to remember the papillary muscles and chordae tendinae! The chordae tendinae are strings that anchor the valve leaflets to the papillary muscles. In healthy people, they prevent the mitral valve leaflet from flipping back into the left atrium. In MVP, the strings become particularly elastic and permit the mitral valve to take an excursion into the left atrium.
MVP- changes with LV size
When the strings are taut and tense, the valve leaflets do not flutter much and are rather quiet. What tenses the strings? Anything the pulls the papillary muscles and the valve leaflets apart. What does that? A large left ventricle! When does the volume of the left ventricle increase? In expiration! So what should happen to the murmur in expiration? It should grow quiet…
When the strings are loose, the valve leaflet is free to flip and flutter. It is like a dog whose leash is loose. Looser the leash, louder the whoosh! What loosens the leash? A small left ventricle. Why? Because the papillary muscle is closer to the mitral valvular orifice and there is hardly any tension in the string! This lets the valve flip and balloon into the left atrium..
The clicks you hear in MVP are because of the sudden tensing of the elastic chordae tendinae..
There you go, folks! This post should whet your appetite to learn more about valve lesions. In fact, very few things in medicine can be as easily reduced to physical mechanics as valve lesions. More on that later…
The Surgical Apprentice 