Dear Dr. Roach: I am almost 96 and in good health. In June, I went to see my oncologist for my 10-year follow-up after a left breast mastectomy. The doctor noted that my heart rate was 48 bpm, and she asked if that was normal. I said I had never heard of such a low heart rate, but I felt fine. The staff took my blood pressure several more times, and it stayed low. She said she was going to call my regular doctor, but I continued to feel fine.
When I called my doctor the next day, he wasn’t too concerned but decided to order an EKG. I didn’t panic because I saw he knew about my low heart rate and had been watching me throughout the years. My question for you, Dr. Roach, is: Is this normal for me? I am not at all afraid to die. I do not want anything to prolong my life, like a pacemaker. Will my heart just stop some day? Right now, I am allowing myself to continue my contented life as is. I’m just curious, since I have never heard about very low heart rates.
Yesterday I took my blood pressure (150/63 mm Hg) and heart rate (48 bpm) after a physical therapy session where I went up and down a long flight of stairs. Today I took it after a morning of sitting and reading the daily newspaper. My blood pressure was 135/65 mm Hg, and my heart rate was 66 bpm.
B.S.
A low heart rate (“bradycardia”) is a common condition. In athletes, it is usually the sign of a healthy heart. However, for a person in her 90s, it is more likely a sign of aging in the electrical system of the heart, specifically the sinoatrial node.
Some medicines can also cause a low heart rate. Every primary care doctor and cardiologist knows to look for medicines that can slow the heart rate, especially calcium channel blockers and beta blockers, but sometimes we forget to check eye drops. Beta blocker drops are still a common treatment for glaucoma, and a few people are so sensitive that they can get very slow heart rates from their eye drops.
In absence of symptoms, a pacemaker isn’t required. Should you develop symptoms, then you can consider a pacemaker. The most common symptoms are lightheadedness and fainting, and a pacemaker can help with these symptoms. Your heart is unlikely to stop altogether because there are “backup” pacemaker systems in the heart. But they work at such a slow rate that you are likely to have symptoms. Pacemakers don’t make people live longer.
Readers may be wondering why your systolic blood pressure (the first or “top” number) went down while your heart rate went up. This is normal physiology. When the heart rate is so slow, the heart gets very full of blood and squeezes out a large volume, causing the blood pressure to go up. With a shorter filling time, the heart squeezes less blood out each beat, so the systolic blood pressure doesn’t get as high. The diastolic pressure isn’t affected much, as the blood vessels return to a relaxed position pretty quickly. However, it isn’t physiologic that your heart rate doesn’t go up with exercise; this shows a problem with your heart.
Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to [email protected]
