Procedure · Houston
A pacemaker treats a heart that goes too slow. A defibrillator treats a heart at risk of going dangerously fast. They are different devices answering different questions, and they are routinely confused.
A pacemaker watches for the heart going too slow and supplies a beat when one does not arrive. It is a floor, not a ceiling. A defibrillator (ICD) watches for a dangerous ventricular rhythm and stops it — by pacing it out or by delivering a shock. Every ICD can also pace; not every pacemaker can defibrillate.
Conflating them leads to real confusion about what a device will and will not do for you. If you leave the office unsure which one is being discussed, ask again.
The usual reasons are sinus node dysfunction — the heart’s own pacemaker slowing or pausing — and heart block, where the signal from the atria fails to reach the ventricles reliably. The symptom that brings people in is fatigue, lightheadedness, breathlessness on exertion, or frank fainting.
The decision rests on matching symptoms to a recorded rhythm. A slow pulse in a fit person may be entirely normal; pauses that correlate with fainting are not.
An ICD is considered either because a dangerous ventricular rhythm has already happened, or because a weakened heart muscle places someone at elevated risk of one. The second situation is a genuine risk-versus-benefit conversation, and it depends on your ejection fraction, the cause of the weakness, how long it has been treated with medication, and what you want.
This is not a decision to make from a web page. It is worth a visit specifically about it.
Pacing from the tip of the right ventricle is the oldest approach and still appropriate for many people. But pacing the ventricle from one spot makes it contract less efficiently, and in someone who is paced most of the time that can matter over years.
Conduction-system pacing — His-bundle and left-bundle-branch-area pacing — places the lead so the heart’s own wiring carries the beat, preserving a more natural contraction. Cardiac resynchronization therapy (CRT) takes a different route to the same goal in a heart with failure and a wide QRS. Which of these applies depends on your ventricle, not on what is newest.
A leadless pacemaker is a self-contained capsule placed directly inside the heart through a vein, with no chest pocket and no wires crossing the shoulder. It removes the complications that come from leads and pockets, which are the parts of a conventional system most likely to cause trouble over time.
It is not the right answer for everyone — what the device needs to do determines whether it fits.
A conventional device is implanted under local anesthetic with sedation, through a small incision below the collarbone. A leadless device goes in through a vein in the leg. Most people stay one night.
You will be given restrictions on lifting and on raising that arm overhead while the leads settle. Those instructions exist to stop a lead from moving before it is anchored — they are worth following exactly.
Modern devices transmit remotely, so much of the follow-up happens without a visit and problems surface before you notice them. Most current devices are MRI-conditional, meaning a scan is possible under defined conditions — tell any radiology department that you have a device, and we will advise them.
Driving restrictions after an ICD depend on why it was implanted and on state rules. Ask about your specific situation rather than assuming; the answer is different for a primary-prevention device than for someone who has been shocked.
Procedures are performed at Houston Methodist, Memorial Hermann, Baylor St. Luke’s, and HCA hospitals across the Texas Medical Center, Clear Lake, and Pearland corridors. Clinic follow-up is at TMC, Clear Lake, or Pearland, Monday–Friday, 8am–5pm. One number: (832) 972-7300.
Dr. Boone evaluates you, performs the procedure, and keeps the follow-up. There is no hand-off to a different physician for the part that matters.
Almost never. A pacemaker delivers a signal well below the threshold you could perceive. What people usually notice is the absence of the symptoms that brought them in.
Yes, a full shock is described as a hard thump in the chest. Many dangerous rhythms are stopped first by rapid pacing that people do not feel at all. If you are ever shocked, that is a call to the office.
It varies with the device and with how much pacing you actually need. Longevity is tracked at every remote check, and the replacement is planned well in advance rather than sprung on you.
Ordinary household electronics and airport screening are not a problem. Keep a phone out of a breast pocket directly over the device. Industrial equipment, arc welding, and strong magnetic fields are worth asking about specifically.
No. Call (832) 972-7300. If a physician is sending records, fax (855) 538-7649.
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If one is being discussed, it is worth an appointment that explains which device, and why that one.
