How to rapidly diagnose significant LV dysfunction at the bed side ?
- Exertional LV S3
- Muffled S1
- Weak carotids
- Often inconspicuous apical impulse
If all these signs are present EF is likely to be less than 35 % with 90 % specificity . If this is accompanied by true cardio-megaly in X-ray chest, LV dysfunction can be diagnosed with a precision reaching almost 100% .
* Tachycardia may be a non specific finding . Further ,base line tachycardia may not be present in all cases of LV dysfunction . When there is a sudden surge in HR even with minimal exertion , it suggests severe LV dysfunction.
** The above clues may not apply in valvular heart disease , and isolated right heart disease as multiple factors may impact S1 intensity .
*** LV failure must be distinguished from LV dysfunction (Vide infra)
Similarly , a patient can not have significant LV dysfunction if one detects any of the following.
- If the first heart sound is loud
- If he feels chest thumping as palpitation.(A fluttering and audible mitral AML has 100 % predictive value for normal LV function )
- If you here an aortic ejection sound (Vascular clicks ) . Ejection clicks need significant force for it’s generation.
The most mobile structure of the heart is anterior mitral leaflet . Fortunately it’s closure is well heard as S1 . Mind you, the most important determinant of S1 intensity is LV contractility. If your ear is sharp , and if you are able to rule out other reasons for soft S1 (Like obesity, pericardial effusion ) we are fairly justified in suspecting significant Left ventricular dysfunction.
Further reading :
***What is the difference between LV dysfunction and LV failure ?
Both these terms are often perceived to convey the same meaning . But it can never be used synonymously .Cardiac failure is a clinical entity while LV dysfunction is a derived technical parameter by and large an echocardiographic entity. Cardiac failure is defined classically as a clinical syndrome .(elevated jvp, edema * S 3 rales etc) Neuro hormonal activation can occur with both.
A patient with LV dysfunction when destabilsed develops LV failure and after stabilisation of LV failure he is brought back to the baseline LV dysfunction.