As late as a decade after Neil Armstrong walked on the moon, doctors could do little to stop a heart attack. They could offer support, something for pain, and drugs to ease the heart's workload and keep blood from clotting readily. They could also halt the rhythm problems that sometimes surfaced. But they didn't have any tools to get rid of an artery-blocking clot and restore blood flow to oxygen-starved heart muscle.

The advent of clot-busters such as tPA and streptokinase changed that. Instead of letting nature take its course, doctors could break the logjam and get blood flowing again. This saved lives and helped preserve heart function.

The overall message on "bad" LDL cholesterol is much the same as it has been: Lower is better and how low your level should be depends on your cardiovascular risk factors.

But the standard for what low LDL means keeps on getting lower. While  an LDL level under 70 is still the usual goal for people at the highest risk for cardiovascular disease perhaps that is still too high.

Thiazide diuretics like hydrochlorothiazide (Esidrix, HydroDIURIL, other brands) continue to be a very effective way to lower blood pressure for people with hypertension. They're inexpensive, and results from large studies have shown them to be at least as effective as other types of blood pressure drugs for most patients.

But if you're taking a diuretic, your potassium levels need to be watched. These drugs direct the kidneys to pump water and sodium into the urine. Unfortunately, potassium also slips through the open floodgates. A low potassium level can cause muscle weakness, cramping, or an abnormal heartbeat, which is especially dangerous for people with heart problems.

If you suffer from cardiac arrest, help is only a 911 call away. Paramedics can use defibrillators to shock your heart back to a normal rhythm. But unfortunately, every minute you spend waiting for their arrival reduces your chance of survival by 10%. Help may soon be closer than your local paramedic and it may come from an unlikely source — someone without medical expertise.

Until recently, witnesses to someone having a cardiac arrest were limited in the help they could provide — calling 911 and performing CPR (cardiopulmonary resuscitation). Now, portable automated defibrillators about the size of a laptop computer are available. These devices not only deliver a shock to restore a regular heartbeat, they also determine whether a shock is really needed, making it possible and safe for people without medical training to use.

Stress tests for the heart: What happens after exercise just as important as what happens during

An exercise stress test measures how the heart responds to and copes with increasing amounts of activity. It can warn of impending heart trouble or monitor the aftermath of a heart attack.

Research suggests that checking not only how the heart does during exercise, but also how the heart recovers from it adds an extra dimension to the test. During a cool-down period, the heart should slow toward its normal rate with a steady pattern of regular, healthy electrical activity. But sometimes the heart may take too long to slow down or may beat irregularly — signs of possible trouble ahead.

This spring the National Institutes of Health revised the guidelines for prevention and treatment of high blood pressure (hypertension) for the first time since 1997. The changes included a new definition of "normal" blood pressure. This meant that 45 million Americans who had gone to sleep with normal blood pressure woke up with higher-than-healthy blood pressure. Here are some of the highlights:

• Normal is now not. What was classified as normal or high-normal blood pressure (a systolic pressure of 120-139 mm Hg and diastolic pressure of 80-89 mm Hg) is now categorized as prehypertension (see chart).

It's a little strange. All of a sudden, the experts are telling millions of people who thought they were healthy that they now have this condition called prehypertension. But the idea is to get Americans and their doctors to take action before the blood pressure climbs any higher - and into the range where the risks of heart disease, stroke, and other problems are pronounced.

Some simple steps can help minimize or avoid muscle problems from Crestor and other cholesterol-lowering drugs.

All drugs have side effects. The trick is to weigh the potential for serious side effects against the gain you can get from the medication. The balance sheet for Crestor and other statins looks like this: These drugs cut the risk of heart attack, angina (chest pain), stroke, and death from cardiovascular disease by 30%. They cause muscle pain in under 5% of the people who take them, and these pains often stop by themselves even with continued statin use. The chance of rhabdomyolysis, a potentially deadly breakdown of muscle tissue, is less than one per million statin prescriptions.

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Vegetables are the bedrock of a healthy diet. They're loaded with vitamins and minerals essential for health, as well as antioxidants (which protect your cells from damage). An observational study published online April 4, 2018, by the Journal of the American Heart Association suggests that eating vegetables is linked to better health of the carotid arteries (in your neck). Researchers looked at ultrasound images of the carotid arteries in about a thousand women (ages 70 or older) and evaluated survey information about what the women ate for a year. Women who said they ate three or more servings of vegetables per day had less thickening of the walls of the carotid arteries, compared with women who said they ate less than two servings per day. Cruciferous veggies — like cabbage, broccoli, and cauliflower — were associated with the strongest benefit. The carotid arteries supply blood to the brain. Thickened walls of the carotids can be a sign of plaque buildup, which paves the way for stroke.