Pulse rate doesn’t mean pacemaker

Dear Dr. Roach: My husband has been on metoprolol for about eight years. He was prescribed that medication right after he had a stent put in due to a clogged heart vessel. He is doing very well. His recent stress test was normal. The metoprolol took his heart rate down to a pulse of between 55 and 60. He is an active 79-year-old. But he was told years ago he may eventually need a pacemaker.

If the metoprolol is giving him a lower heart rate, causing a future need for a pacemaker, I would think the cardiologist would just give him a different blood pressure prescription that doesn’t lower the heart rate. He does not want a pacemaker. Do you think a replacement for the metoprolol would keep his pulse in the normal range and dismiss the thought of a future pacemaker? — N.F.

Metoprolol is a beta blocker, and it works mainly by slowing the heart rate down and by decreasing how hard it contracts. Beta blockers reduce the risk of further heart attacks and death in people with coronary artery disease, and they should be given to most people with CAD. They also may act to reduce rhythm disturbances by counteracting adrenaline in the blood.

A heart rate of 55-60 is not unusual in people taking metoprolol. However, if a person had a heart rate that slow without a beta blocker, a doctor would be concerned that they would eventually develop symptoms from that slow of a heart rate. Symptomatic slow heart rate is a clear indication for a permanent pacemaker, and extreme bradycardia (below 40) gets most cardiologists concerned enough to start thinking about a pacemaker even without symptoms.

In your husband’s case, if his heart rate were to prove too slow, his cardiologist would likely reduce the dose of the metoprolol, or even switch it out for a different drug.

Write to Dr. Roach at ToYourGoodHealth@ med.cornell.edu or mail to 628 Virginia Dr., Orlando, FL 32803.