Echocardiogram is an ultrasound examination of the heart It is used to evaluate the anatomy and the function of the heart. A cardiologist is required to interpret this test and can evaluate the heart muscle and determine how thick it is, whether it moves appropriately, and how efficiently it can push blood out to the rest of the body. The echocardiogram can also assess heart valves, looking for narrowing (stenosis) and leaking (insufficiency or regurgitation). A chest X-ray may be used as a screening test to look for heart size, the shape of the aorta, and to assess the lungs.
^ Xie, X; Atkins, E; Lv, J; Bennett, A; Neal, B; Ninomiya, T; Woodward, M; MacMahon, S; Turnbull, F; Hillis, GS; Chalmers, J; Mant, J; Salam, A; Rahimi, K; Perkovic, V; Rodgers, A (30 January 2016). "Effects of intensive blood pressure lowering on cardiovascular and renal outcomes: updated systematic review and meta-analysis". Lancet. 387 (10017): 435–43. doi:10.1016/S0140-6736(15)00805-3. PMID 26559744.
As for when to check your blood pressure, the most important thing is to do it consistently the same time of the day (ask the doctor which time he prefers and also what time in relation to taking your medication). The following article has a lot of good information for someone just starting to monitor their blood pressure:

One especially important cause of low blood pressure is orthostatic hypotension, which is sometimes referred to as postural hypotension. This happens when blood pressure drops rapidly during changes in body position—usually when changing from sitting to standing—inducing classic signs that the blood pressure is too low, like dizziness, blurry vision, and fainting.
Stress reduction techniques such as biofeedback or transcendental meditation may be considered as an add-on to other treatments to reduce hypertension, but do not have evidence for preventing cardiovascular disease on their own.[125][126][127] Self-monitoring and appointment reminders might support the use of other strategies to improve blood pressure control, but need further evaluation.[128]
However, sometimes a high reading can occur temporarily and then your numbers will return to normal. If your blood pressure measures at this level, your doctor will likely take a second reading after a few minutes have passed. A second high reading indicates that you’ll need treatment either as soon as possible or immediately depending on whether or not you have any of the symptoms described above.
NHLBI Expert Panel on Cardiovascular Health and Risk Reduction in Children and Adolescents. We have supported the development of guidelines based on up-to-date research to evaluate and manage risk of heart disease in children and adolescents, including high blood pressure. Visit Expert Panel on Integrated Guidelines for Cardiovascular Health and Risk Reduction in Children and Adolescents for more information.
African-Americans are at greater risk of developing hypertension than people of other races. African-Americans develop high blood pressure earlier in life and have more difficulty achieving blood pressure goals. Some studies suggest that African-Americans may be more sensitive to salt than other races. For those who are genetically prone to salt sensitivity, a small amount (half-teaspoon) of salt can raise blood pressure by 5 mm Hg. Dietary factors and being overweight can also raise blood pressure.
Everyone age 3 or older should have their blood pressure checked by a healthcare provider at least once a year. Your doctor will use a blood pressure test to see if you have consistently high blood pressure readings. Even small increases in systolic blood pressure can weaken and damage your blood vessels. Your doctor will recommend heart-healthy lifestyle changes to help control your blood pressure and prevent you from developing high blood pressure.

Making sure your blood pressure numbers are normal is an investment for your future. Putting unnecessary strain on your arteries and your heart can ultimately lead to a heart attack or stroke. Heart disease and strokes are the leading causes of death in the United States. About 1,000 people die every day from complications stemming from high blood pressure.

In normal blood pressure for elderly & adults over 50, increased systolic blood pressure is a major risk factor for heart disease. Systolic blood pressure tends to increase steadily over time due to stiff arteries, a build-up of plaque, and a higher rate of cardiac and vascular disease. This means older adults need to be even more vigilant about monitoring their blood pressure.
tilt table test – usually recommended if your doctor suspects you might have orthostatic hypotension or NMH (During this diagnostic test, a person lies on a table and then the table is tilted to raise the upper part of their body. This simulates the change in position from sitting or lying down to standing up. People with orthostatic hypotension or NMH may feel dizzy, lightheaded, or even faint when their position changes.) 

With low blood pressure, the patient may feel faint or lose consciousness. This is due to lack of blood flow to the brain, and usually laying the patient supine will help them come round. This is also known as a blackout, and it could be accompanied by a dizzy feeling and light-headedness. Generally, your patient will report trouble focusing, difficulty keeping upright and lack of coordination.
If these lifestyle changes don't lower your blood pressure to a safe level, your doctor will also prescribe medicine. You may try several kinds or combinations of medicines before finding a plan that works best for you. Medicine can control your blood pressure, but it can't cure it. You will likely need to take medicine for the rest of your life. Plan with your doctor how to manage your blood pressure.
Health care providers measure blood pressure with a sphygmomanometer (sfig-mo-muh-NAH-muh-ter), which has a cuff that's wrapped around the upper arm and pumped up to create pressure. When the cuff is inflated, it squeezes a large artery in the arm, stopping the blood flow for a moment. Blood pressure is measured as air is gradually let out of the cuff, which allows blood to flow through the artery again.
Blood pressure changes throughout the day and varies from person to person. Various factors affect blood pressure, including your body position, breathing rhythm, stress level, physical activity, medications, what you eat or drink, and the time of the day (blood pressure is usually lowest at night when you sleep and rises when you wake up). In healthy individuals, your body responds and adapts to these changes to keep your blood pressure within a normal range. This ensures that vital organs, such as your brain and kidneys, receive a constant blood flow and nutrient supply.
Genetics plays a role in hypertension, and much of essential hypertension could ultimately turn out to be genetic in origin. Genes are believed to have approximately 30 percent to 50 percent impact on blood pressure. Specific genes have not been identified as responsible for hypertension, however. This may be due to the fact that there are many genes that interact together to influence blood pressure, with some of these genetic variants being more common than others.
Low blood pressure is also known as hypotension. This is usually defined in an adult as a systolic recording of less than 90 mmHg, although it has been suggested that for elderly people, below 110 mmHg is a more appropriate definition. Blood pressure and heart rate are controlled by the autonomic nervous system (the nervous system that controls bodily functions that we do not have to think about).                                                                                                                                                                                                
For older people, often the first number (systolic) is 130 or higher, but the second number (diastolic) is less than 80. This problem is called isolated systolic hypertension, which is due to age-related stiffening of the major arteries. It is the most common form of high blood pressure in older people and can lead to serious health problems (stroke, heart disease, eye problems, and kidney failure) in addition to shortness of breath during light physical activity, lightheadedness upon standing too fast, and falls. Isolated systolic hypertension is treated in the same way as regular high blood pressure (130 or higher for the first number, or 80 or higher for the second number) but may require more than one type of blood pressure medication. If your doctor determines that your systolic pressure is above a normal level for your age, ask how you can lower it.
If your blood pressure remains high for a long period of time, you run the risk of damaging your blood vessels. Your stroke risk rises significantly, too. And because your heart is working harder to push blood through your system, that very valuable muscle can become overworked and grow thicker. An enlarged heart causes further complications, including heart failure. Medications and special implantable pumps can help boost heart function. But if you can manage your blood pressure before it gets too high and puts your heart at risk, you may be able to avoid a lot of complications down the road.
Vasovagal reaction is a common condition in which a healthy person temporarily develops low blood pressure, slow heart rate, and sometimes fainting. A vasovagal reaction typically is brought on by emotions of fear or pain such as having blood drawn, starting an intravenous infusion, or by gastrointestinal upset. Vasovagal reactions are caused by activity of the involuntary (autonomic) nervous system, especially the vagus nerve, which releases hormones that slow the heart and widen the blood vessels. The vagus nerve also controls digestive tract function and senses activity in the digestive system. Thus, some people can have a vasovagal reaction from straining at a bowel movement or vomiting.
Wear a blood pressure monitor. This monitor is attached to you. You will be asked to wear it for 24 hours. The monitor is usually programmed to take blood pressure readings every 15 to 30 minutes all day and night while you go about your normal activities. The doctor will evaluate the results. In some cases, home blood pressure monitors may also be used to evaluate the effectiveness of your treatment.
Understanding the normal BP range with age can help the doctor and you to estimate your cardiovascular health. Blood pressure levels can fluctuate significantly from one reading to the next and it is important to remember that just one abnormally high reading does not signify that you have high blood pressure. Doctors usually use an average of multiple blood pressure readings taken over a period of several days to arrive at a diagnosis of high blood pressure.
The cause for hypertension is not always known, although it can develop as a result of other health conditions including: sleep apnea, kidney problems, and thyroid issues. Beyond chronic health conditions, risk factors for hypertension include age, the amount of salt you eat, being overweight or obese, using tobacco, drinking excessively, not exercising, and having too little potassium in your diet.
Blood pressure readings fall into four general categories, ranging from normal to stage 2 high blood pressure (hypertension). The level of your blood pressure determines what kind of treatment you may need. To get an accurate blood pressure measurement, your doctor should evaluate your readings based on the average of two or more blood pressure readings at three or more office visits.