What happens when the heart beats too slowly or too fast
March 3, 2026By: Ethan Hacker, MD
Categories: Heart & Vascular
The heart relies on a built-in electrical system to keep blood moving through the body in a steady rhythm. A small group of cells at the top of the heart send out an electrical signal that starts each heartbeat. The signal makes the top chambers squeeze and push blood into the bottom chambers. A brief pause gives the heart time to fill with blood before the signal tells the bottom chambers to push blood out to the lungs and the rest of the body. After each beat, the heart resets and gets ready for the next signal. This occurs 60 to 100 times a minute.
Here are the Top 5 Takeaways from my presentation, “Life-Saving Technology: How Pacemakers and Defibrillators Protect Your Heart”:
- Problems occur when the heart beats too slowly or too fast: A slow heartbeat can leave you feeling weak or dizzy and may cause fainting. A fast heartbeat feels like pain or fluttering in the chest.
- Bradycardia occurs when the heart beats too slowly: It can be caused by aging, infections, medication or illness.
- Tachycardia happens when the heart beats too quickly: This occurs when the heart muscle becomes irritated, scar tissue forms in the heart or it may be an inherited condition.
- Transvenous pacemakers help when the heart beats too slowly: The device sits under the skin and sends electrical signals to the heart through thin wires.
- Defibrillators help steady a quick heartbeat: They work like a pacemaker and give a strong shock to reset the heart.
Watch the presentation
Sign up for our monthly eNews email list to learn about new Let’s Talk Health events or view a list of upcoming classes at nkchealth.org/Class
