Brief Answer:
Most likely clogged up vessel in leg can be a cause.

Detailed Answer:
Hello,
Thanks for asking your query on HealthcareMagic.
I am a Cardiologist and would be answering your query.

As per your query answers are-
Leg swelling can be related to fluid buildup. Leg swelling caused by the retention of fluid in leg tissues is known as peripheral edema. It can be caused by a problem with the circulatory system, the lymphatic system or the kidneys.Blood clots in the vein inside legs can lead to swelling of leg around calf muscle.Excess body weight or sitting or standing in same position for long period of time can also cause unilateral edema.Excess body weight can decrease blood circulation, causing fluid to build up in the lower extremeties.Maintaining same posture for long periods makes the muscles inactive, they can't pump body fluids back up toward the heart. The retention of water and blood can cause swelling in the legs.

Most likely its not related to your heart as edema caused due to cardiac reason will be bilateral(it will be there in both limbs).
Most likely there can be some circulatory problem in your case.

I would suggest you to go for doppler scan of left leg to rule out thrombosis of any vessel in leg.
A peripheral smear of blood should be done for parasite microfilaria.

Though amlodipine can also cause calf edema but again it is bilateral.

So go for color dopper of leg involved and follow up with reports.

Hope i answered your query well.
In case you need further details feel free to ask.

Thanks.

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