Reader: I am a woman in my early 60s. Since age 12 or so, I could feel my heart pounding and racing. During treatment at a hospital, I set off the heart monitor. I am sending my latest thyroid test results and the Holter monitor test results.

Dr. Zipes: Your thyroid results indicate an under-acting thyroid (hypothyroid). The Holter test shows your heart rate varied between 52 and 129 beats per minute in 24 hours. This is not at all unusual, as during sleep your heart rate slows, and during activity it speeds. I would like to see the ECG strips that set off the alarm during your hospitalization. They may provide more insight into what is causing your palpitations than did the Holter test.

Reducing Cardiac risk

Reader: Before age 69, I was told that "scar tissue reveals patient had heart attack." It's hard to know when. I take HCTZ, Toprol XL, and Diovan. I am now 73. Am I apt to have another heart attack?

Dr. Zipes: The heart is a muscle and requires a blood supply to provide oxygen and nutrients in order to survive and function, just as do other muscles in the body. When the blood supply in the coronary arteries that nourish the heart is cut off, a heart attack can result, causing death of heart muscle and subsequent scar formation. You know that when you cut your finger, it heals and leaves a scar. Damage to the heart follows a similar healing process. It is difficult to say whether you are at risk for another heart attack, although people with a prior attack are at greater risk for a second one compared to those who have not had one. The presence of a heart attack indicates that they have some obstruction to blood flow in the coronary arteries. You need to pay attention to common risk factors such as elevated cholesterol, high blood pressure (it sounds like yours is being treated), obesity, smoking, inactivity, and diet. Check to be sure you do not have diabetes, and if you do, treat it appropriately. Usually a baby aspirin is prescribed, along with beta blockers (you are already taking one in the form of Toprol), statins to reduce cholesterol, and often a drug called an ACE inhibitor. You need to check with your cardiologist as to your risk of having a future heart attack and what you need to do to prevent it from occurring.

Chronic Chest Discomfort

Reader: I have had two angioplasties and a heart attack in 2004. Some months ago, I had a nuclear stress test and pulmonary test. They said both heart and lungs are pretty good. I still get out of breath so easy and am dizzy a lot. I take nitroglycerin every now and then. It takes away the slight pain and heavy feeling that I get in my chest. My shoulders and neck both ache after using my arms a lot. I take 12 prescriptions, including insulin.

Hope you might give me some insight into my problem. Both my parents and all grandparents died of heart and/or related problems.

Dr. Zipes: From your description, you definitely have obstructions to blood flow in your coronary arteries that have caused your heart attack and probably the "slight pain and heavy feeling," as well as the ache in your shoulders and neck after using your arms a lot. This discomfort sounds like angina, which is due to the heart not getting enough blood flow. The angioplasties you have had were procedures to open up the clogged arteries. The fact that the nuclear stress test is "pretty good" is a helpful sign that the obstructions are not too significant at present. You need to be sure that all your risk factors are under control, the point I made to the other reader.

Sick Sinus Syndrome

Reader: I was diagnosed in 1998 with congestive heart failure and also something called sick sinus syndrome, about which I can find no info at all. Can it be fixed with surgery? Can you give me some advice on what to do?

Dr. Zipes: Sick sinus syndrome is a disorder of the primary pacemaker of the heart, the sinus node, causing it to beat too slowly. It is a fairly common disorder and is often treated by a pacemaker. Some people can also have the so-called bradycardia-tachycardia syndrome associated with the sick sinus syndrome. In that disorder, patients have slow beating of the sinus node (bradycardia) interspersed with rapid heartbeats, often due to atrial fibrillation (tachycardia).

You need to find a heart rhythm expert, called an electro-physiologist, to help deal with the problem, as there are a range of therapy options. I suggest you check out the Web site of the Heart Rhythm Society, an organization made up of such experts, and find a doctor close to your home. Good luck. Let me know if you need more specific help.