Why is there fatigue as a symptom in mild to moderate Mitral Regurgitation
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mitral regurgitation fatigue symptoms mechanism authoritative source
Mild chronic mitral regurgitation is usually asymptomatic. Fatigue is more likely with moderate MR or when MR has begun to affect exercise capacity.
Mechanism:
- During systole, some LV stroke volume leaks backward into the left atrium instead of moving forward into the aorta.
- The heart may still eject a normal or even high total stroke volume, but the effective forward cardiac output can be lower, especially during exercise.
- To compensate, the LV works harder and gradually dilates. The increased workload and inability to raise forward output adequately with exertion can feel like early fatigue.
- If left-atrial pressure rises, mild pulmonary venous congestion can develop, causing exertional breathlessness. The extra work of breathing also contributes to fatigue.
- Later, atrial enlargement, atrial fibrillation, pulmonary hypertension, or LV dysfunction can worsen fatigue substantially.
A nuance: fatigue in someone labelled as having mild MR should not automatically be attributed to the valve lesion. Anemia, thyroid disease, deconditioning, sleep problems, medications, coronary disease, arrhythmia, and other cardiac or pulmonary disorders may be responsible. Textbooks describe mild chronic MR as generally asymptomatic, with fatigue appearing as pulmonary congestion or LV failure develops. Bailey and Love's Short Practice of Surgery, Clinical features.
Why does palpitations occur in MR, AR
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mitral regurgitation aortic regurgitation palpitations mechanism arrhythmia
Palpitations are the awareness of one’s heartbeat. In MR and AR they may arise either from a forceful high-output beat or from an actual arrhythmia.
Mitral regurgitation (MR)
The main mechanism is often left atrial enlargement leading to atrial fibrillation (AF):
- MR causes systolic backflow from the LV into the left atrium.
- Over time, the left atrium receives excess volume and dilates.
- A stretched, fibrotic atrium is prone to atrial ectopic beats and AF.
- AF produces an irregular, often rapid ventricular rhythm, felt as fluttering, racing, skipped, or pounding beats.
LV dilatation/dysfunction in advanced MR can also predispose to ventricular ectopics or other arrhythmias. In patients with mitral valve prolapse, palpitations can occur even with little MR, often due to autonomic symptoms or ectopic beats. Chronic MR palpitations are commonly due to AF, as summarized in the Merck MR reference.
Aortic regurgitation (AR)
In AR, palpitations are often initially due to awareness of a hyperdynamic, high-stroke-volume LV, rather than an arrhythmia:
- During diastole, blood leaks from the aorta back into the LV.
- The LV becomes volume overloaded and ejects a large stroke volume.
- This causes a forceful apical impulse and wide pulse pressure.
- The patient perceives the strong pulsation as a pounding heartbeat, often more noticeable when lying down or at night.
With longstanding severe AR, LV dilatation, hypertrophy, and eventual LV dysfunction can lead to atrial or ventricular arrhythmias, making palpitations irregular as well. Harrison's specifically notes that the enlarged LV and hyperdynamic precordium in AR often create this sensation. Harrison’s Principles of Internal Medicine, “Palpitations.” The Merck AR reference also lists palpitations among typical symptoms.
High-yield difference:
| Lesion | Usual reason for palpitations |
|---|---|
| MR | LA enlargement causing AF or other atrial arrhythmias |
| AR | Forceful hyperdynamic heartbeat from high stroke volume; arrhythmia occurs later if the LV decompensates |
Indications of mitral valve repair in MR
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2025 guideline primary mitral regurgitation mitral valve repair indications LVEF LVESD atrial fibrillation pulmonary hypertension
Indications for mitral-valve intervention in mitral regurgitation
First confirm that MR is severe and distinguish primary (degenerative/organic) from secondary (functional/ischaemic) MR. In primary MR, surgical mitral valve repair is preferred over replacement when a durable repair is likely.
A. Severe primary MR: surgical repair is indicated
| Situation | Indication |
|---|---|
| Symptomatic severe primary MR | Repair is indicated if the patient is operable and a durable repair is feasible. |
| Acute severe MR | Urgent surgery, especially with acute pulmonary edema, hypotension, or cardiogenic shock. Examples: papillary-muscle rupture after MI, infective endocarditis, chordal rupture. |
| Asymptomatic severe MR with LV dysfunction | Surgery even without symptoms if LVEF ≤60% and/or LV end-systolic diameter (LVESD) ≥40 mm. In MR, an EF of 60% is already abnormal because EF can look falsely preserved due to ejection into the low-pressure left atrium. |
| Asymptomatic severe MR with new AF | Surgery should be considered if AF is attributable to MR and repair is likely to be durable. |
| Asymptomatic severe MR with pulmonary hypertension | Surgery should be considered if resting systolic pulmonary artery pressure is >50 mmHg, after confirming pulmonary hypertension when needed. |
| Severe primary MR when another cardiac operation is planned | Repair the mitral valve during CABG, aortic-valve surgery, or another indicated cardiac surgery. |
| Selected low-risk asymptomatic patient with preserved LV function | Early repair may be considered in a high-volume valve center if repair success is highly likely and operative risk is very low, particularly with progressive LV enlargement, marked LA dilatation, or high likelihood of developing AF/pulmonary hypertension. |
This approach is consistent with ESC guidance on primary MR.
B. Severe secondary MR: repair is more selective
Secondary MR is due to LV or LA disease, not primarily diseased valve leaflets.
- First optimize guideline-directed heart-failure treatment, including CRT where appropriate.
- If the patient undergoes CABG or other cardiac surgery, concomitant mitral surgery may be considered, particularly with severe MR.
- If severe symptomatic MR persists despite optimal therapy and anatomy is suitable, transcatheter edge-to-edge repair (TEER, for example MitraClip) is often favored in patients with high surgical risk.
- Surgical repair/replacement may be considered in selected suitable patients, but recurrence after repair can be an issue in ischaemic/functional MR.
Short exam answer
Indications for mitral valve repair in severe primary MR:
- Symptomatic severe MR
- Asymptomatic MR with LV dysfunction: EF ≤60% or LVESD ≥40 mm
- New-onset AF due to MR
- Resting pulmonary hypertension: sPAP >50 mmHg
- Severe MR requiring another cardiac surgery
- Acute severe MR, usually urgent surgery
- Selected asymptomatic low-risk patients if a durable repair is highly likely at an experienced valve center
Remember: repair is preferred to replacement when a durable repair is technically likely.
Does Atrial fibrillation predisposes to thrombosis?
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atrial fibrillation blood stasis left atrial appendage thrombus stroke mechanism guideline
Yes. Atrial fibrillation (AF) predisposes to thrombus formation, especially in the left atrium and left atrial appendage.
Why?
Normally, atrial contraction helps empty blood from the atria. In AF, the atria quiver instead of contracting effectively:
AF → ineffective atrial emptying → blood stasis, especially in left atrial appendage → thrombus formation → systemic embolism
If a part of the thrombus embolizes, it can cause:
- Ischaemic stroke: most important complication
- Acute limb ischaemia
- Renal or splenic infarction
- Mesenteric ischaemia
This is especially relevant in mitral stenosis or MR with marked left atrial enlargement, heart failure, older age, hypertension, diabetes, and prior stroke/TIA.
This follows Virchow's triad:
- Stasis: dominant mechanism
- Atrial/endocardial structural change
- Increased prothrombotic tendency in some patients
Not every person with AF needs the same anticoagulation. Stroke-prevention treatment is chosen using an individual risk score such as CHA₂DS₂-VASc, while accounting for bleeding risk. In AF with moderate-to-severe rheumatic mitral stenosis, warfarin is generally used rather than a DOAC.
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