What is heart block?

Heart block is an abnormal heart rhythm where your heart beats much slower than it should, due to a malfunction in the heart’s electrical system.

Your normal heart rate is between 60 and 100 beats per minute, and the electrical signals telling the heart to beat are moving smoothly between the heart’s upper chambers (atria) to the lower chambers (ventricles).

If you have heart block, your heart beats fewer than 60 times per minute because electrical signals from the atria aren’t transmitting properly to the ventricles. This condition is also sometimes known as atrioventricular block.

Heart blocks are classified based on the degree to which signals from the atria reach the ventricles, the heart’s main pumping center.

Types of heart block

  • First-degree heart block: electrical impulses reach the ventricles successfully, but they are slowed.
  • Second-degree heart block (Type 1): not all of the signals reach the ventricles. Some heartbeats are dropped altogether. Your heartbeat is slower and irregular.
  • Third-degree heart block (Type 2 or complete heart block): None of the electrical signals reach the ventricles. In the absence of signals, the ventricles may generate some of their impulses, called ventricular escape beats.
  • Bundle branch heart block: the interruption of electrical signals as they travel through specialized conducting tissue.

Diagnosis of heart block

Your physician will take a detailed medical history and go over the symptoms you’re experiencing. To confirm the diagnosis, you may undergo any or all of the following tests:

  • Electrocardiogram (ECG)
  • You may be asked to wear a portable ECG, also called a Holter Monitor
  • Electrophysiology study

Once a detailed diagnosis is reached, your physician will determine your best treatment options.

Treatment at Penn Medicine

Your treatment will depend on the severity of your condition. If you have first-degree heart block, you usually don’t require any intervention or treatment. If your condition is more advanced, your heart may need support to beat normally. The most common way to treat heart block is with the implantation of a pacemaker.

Specialists at Penn Medicine excel in the care of heart rhythm disorders, and our physicians provide state-of-the-art treatment for the most complex cases. Each year, Penn physicians implant more than 650 pacemakers and place more than 675 implantable defibrillators. Penn Medicine electrophysiologists have been at the forefront of the field for a quarter of a century, pioneering new therapies for life-threatening heart rhythm disorders.

When you choose Penn Medicine for your treatment, you work with a dedicated team offering the most innovative treatments and surgeries.

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