Ask The Doctors: January 2013
Q. Ever since my first heart attack four years ago, I’ve been worried about a second heart attack. I have two stents and am eating better and exercising more than years ago. But what is the risk of a second heart attack, and do they tend to be much more serious?
A. Coronary artery disease (CAD) is a disorder of the blood vessel walls, in which cholesterol accumulates, forming plaques, accompanied by inflammation when the body’s white blood cells try to remove the cholesterol. CAD generally makes its presence known when a heart attack or myocardial infarction (MI) occurs, but can also show itself by chest discomfort or angina. In some persons, no symptoms are experienced, a condition known as “silent ischemia.” But in your case, you experienced an MI requiring stents to re-establish blood flow through the coronary vessels. Even though stents have been placed, CAD is still present, and requires pharmacologic treatment and lifestyle modification in order to lower risk.
Once a person has experienced an MI, their risk of another cardiac event can be roughly estimated at about 2 percent per year. However, appropriate treatment with statin drugs, aspirin, and other medications can reduce that risk. And your efforts at improved diet and exercise will improve your chances as well. Even so, the risk of a second heart attack will still be between 1 and 2 percent, since the CAD in the vessel walls does not disappear. In general, future events do not tend to be more severe than the first. Being more attuned to your body’s warning signs, in terms of symptoms, should also help you come to medical attention sooner, before a narrowing in a coronary artery becomes complete. Working with your cardiologist can help reduce the risk of a second MI.
Q. What is the “official” opinion of caffeine use if you have heart disease? I’ve heard conflicting views. I have mitral valve prolapse and was recently diagnosed with atrial fibrillation. I take medication for the Afib and for high cholesterol. Do I need to give up coffee?
A. Numerous studies have been performed in order to determine if caffeine intake increases the risk of heart disease and cardiovascular events such as myocardial infarction (MI) or stroke. However, the sum total of this research suggests that mild-to-moderate intake of caffeine (for example, one to two cups of coffee per day) does not confer additional risk. Studies have attempted to establish a link between caffeine intake and cancer, which have likewise been negative. Rather, other behaviors associated with caffeine intake (such as tobacco use) have generally been the culprits for harm.
Caffeine influences the body in several ways, by stimulating the central nervous system, raising heart rate and blood pressure, and increasing kidney function and urine output. The same effects which lead to that familiar “jolt” from a morning cup of coffee can influence the heart in adverse ways, as well. Your diagnosis of atrial fibrillation (afib) may alter how you and your doctor view caffeine. While caffeine does not appear to cause CAD, it certainly does make the heart more “irritable,” leading to more frequent extra beats such as premature ventricular contractions (PVCs) and premature atrial contractions (PACs). PVCs and PACs may be clinically silent, or lead to serious symptoms of palpitations (the sense of an irregular, fast, or otherwise abnormal heartbeat). For people with a history of arrhythmias, such as afib, caffeine can cause episodes of afib, prolong them, and make them more severe. These experiences don’t hold true for everyone, but are frequent enough for most people with afib to try abstaining from caffeine for a period of time (weeks to months), in order to see if this will improve their symptoms. Also remember that other foods and drinks, including chocolate, cola, and tea can contain substantial amounts of caffeine. While some individuals need to pursue total abstinence from caffeine, others can continue to enjoy their morning cup of coffee without consequences.