What could be the reason that I am falling unconscious? I am having severe chest pain and sometimes blood flow to the heart stops, My age is 20 years and weight is 47Kgs, Please suggest.

Issues with pacemakers can cause dizziness, shortness of breath, and an irregular pulse. Improper functioning or infection may lead to these complications. It's crucial to seek medical help promptly if you experience these symptoms. Solutions may involve adjusting the pacemaker's settings or replacing the device entirely.

In anaemia, your heart will try pumping more blood to compensate. This causes palpitations and increases the heart rate. 

Mechanical valves are safe for most patients, even for those who are 65 years old but there are some risks. Patients with mechanical valves need to take blood thinning medication for the rest of their lives to prevent blood clots from forming on the valve, which can be a serious complication.

Please visit a doctor in person. This will help in better evaluation and diagnosis. Based on that, the doctor will suggest some medications etc. to manage the heart rate and CAD. Also, it is important to regularly monitor the blood work to see if the medications are working and the condition is not worsening. 

Get checked for stroke risk factors like high blood pressure, high cholesterol, and diabetes. Be aware of stroke symptoms like trouble speaking, seeing, moving. Call doctor immediately if you have them

Your symptoms can indicate a high blood pressure that causes headaches, sweating and shortness of breath. The pain in the back of your left shoulder is muscular strain. Yet, one should consider the visit of a doctor maybe cardiologist to uncover any substantial underlying conditions and receive appropriate treatment.

This can be indicative of various underlying medical issues, specifically when you are experiencing fainting problems. Seek immediate medical attention immediately for a proper evaluation and diagnosis.

A blood pressure reading of 145/112 mmHg falls under the category of Stage 2 hypertension. You should visit a cardiologist for further evaluation and don't delay. High blood pressure can lead to serious health complications such as heart attack and stroke.

It may be due to stress or anxiety. In such cases, it is advisable to practice mindfulness meditation, deep breathing and some relaxation exercises. Also, knowing the cause of your stress and anxiety may help. If the problem still continues, please consult a reputed doctor to address the issue. I hope this helps.