Definitely Yes, it is proved beyond doubt, that regular practice of Pranayama and Meditation is beneficial in improving the cardiovascular functions.

Yes it scientifically proven, alternate nostril breathing balances functioning of both the hemispheres of brain and it helps to activate alpha waves of  brain which will calm it down.And thus heart functions are regulated effectively.Practise it twice a day for 9 rounds.You will see effective change in just one week.

Yes pranayamas are scientifically proven ! Many researches show that Alternate nasal breathing has a calming, effect. It if performed with a cooling pranayama(chandra anuloma viloma) stabilizes your blood pressure. Also , yes is very beneficial for cardiac function thus!

Pranayama is good for health when done with well trained professionals.

Pranayama is very beneficial for cardiac functions , as pranayama regulates the breathing pattern it improves the lung capacity inturn which improves the vital signs such as heart beat so the cardiac muscles will receive good blood supply

It is Good I agreed Yoga Best Option For Body Fitness and illness

It is beneficial when done over a period of time. At least 6 months to 1 yr.

Yes it scientifically proven and very beneficial to lower the blood pressure. Alternate nostril breathing balances the functioning of the brain. The heart functions are regulated effectively. Practice it twice a day, start with 3 rounds and then gradually increase up to 5, 7 and up to 9 rounds. The effect will be seen in 15 days of continuous practice.