The CRT medical abbreviation has several meanings, and in heart care it stands for cardiac resynchronization therapy, a special pacemaker that helps both lower chambers of the heart squeeze together. In nursing assessments the same letters mean capillary refill time, and in cancer care they can mean chemoradiotherapy.
With meanings this far apart, where the note was written usually decides the question. A cardiology device clinic letter, an emergency triage note and an oncology plan each use CRT their own way. This guide walks through all three, with sample lines and the shorthand that usually sits nearby.
At a glance
Stands for
Cardiac resynchronization therapy (cardiology)Other meanings
Capillary refill time (nursing); chemoradiotherapy (oncology); certified respiratory therapistDevice forms
CRT-P (pacing only), CRT-D (with defibrillator)Also called
Biventricular pacing, BiV pacemakerRelated devices
Specialty
Cardiac electrophysiology, heart failure clinics
Cardiac resynchronization therapy explained
In some people with heart failure, the electrical signal spreads unevenly, so the left and right ventricles squeeze slightly out of time. This shows on an EKG as a wide QRS, often with a pattern called left bundle branch block. The uncoordinated squeeze makes a weak heart pump even less efficiently.
A CRT device has leads in the right atrium, the right ventricle and a vein on the outside of the left ventricle. It paces both ventricles together, which can improve symptoms and pumping in people who qualify. Candidates usually have heart failure with a low ejection fraction, often about 35 percent or lower, along with a wide QRS, but the cardiology team weighs each case.
CRT-P, CRT-D and how device notes read
A CRT-P only paces. A CRT-D also works as a defibrillator, able to shock a dangerous fast rhythm, like an AICD. Many people who need resynchronization also qualify for a defibrillator, so CRT-D is common.
| Note text | Meaning |
|---|---|
| NICM | Nonischemic cardiomyopathy, a weak heart muscle not caused by blocked arteries |
| EF 25% | The left ventricle pumps out about a quarter of its blood each beat |
| LBBB, QRS 160 ms | A conduction delay making the QRS wide |
| refer for CRT-D | Send to the device team for a resynchronization defibrillator |
Capillary refill time in nursing assessments
In nursing and emergency notes, CRT usually means capillary refill time. The examiner presses on a fingernail or the skin until it turns pale, lets go, and counts the seconds until color returns. In a warm room, a healthy person's color usually returns in about two seconds or less, though cold fingers and age can slow it.
Triage note: "Skin warm and dry, CRT less than 2 sec, radial pulses strong." Here CRT has nothing to do with the heart device; it says blood flow to the fingertips looks normal. Children's assessments use this sign often, alongside heart rate and breathing.
Some charts write cap refill instead, which avoids the clash with the cardiology meaning.
CRT in oncology and as a credential
In cancer care, CRT can stand for chemoradiotherapy, also written chemoradiation, meaning chemotherapy and radiation therapy given during the same period. It is used for some cancers of the head and neck, esophagus, rectum, cervix and lung. Oncology notes might read "definitive CRT" or "neoadjuvant CRT before surgery." Radiation alone is usually written XRT.
After a name, CRT can be a credential for a certified respiratory therapist, an entry level respiratory therapy certification. Related staff titles appear under RT.
Spotting which CRT medical abbreviation a note uses
| What the note mentions | Probable meaning |
|---|---|
| EF, QRS, leads, device check | Cardiac resynchronization therapy |
| Seconds, skin color, pulses | Capillary refill time |
| Gy, cycles, tumor, oncology | Chemoradiotherapy |
| After a staff name | Certified respiratory therapist |
When context still leaves doubt, ask whoever wrote it. Device implants and other procedures are grouped in the surgical abbreviations guide.
Living with a resynchronization device
Device implantation is usually done with local numbing and sedation, often with an overnight stay. Afterward, people return to the clinic for device checks on a set schedule, often with remote monitoring from home. Reports from these checks mention the percentage of beats that were biventricular paced, battery status and any rhythms recorded. A high percentage of paced beats is generally the goal so the therapy works as intended.
This general overview cannot speak to any one person's heart or device. Your cardiologist or device clinic is the place to ask about your own settings and checks.
Frequently asked questions
What does CRT mean in cardiology?
It means cardiac resynchronization therapy, a pacemaker system that paces both ventricles so they contract together. It is used for selected people with heart failure and a wide QRS.
What is the difference between CRT-P and CRT-D?
CRT-P paces the heart only. CRT-D also includes a defibrillator that can treat dangerous fast rhythms with a shock.
What does CRT less than 2 seconds mean?
It refers to capillary refill time, meaning color returned to the pressed skin or nail in under about two seconds. That is generally read as normal blood flow to the area.
Can CRT mean chemoradiation?
Yes. In oncology notes, CRT often stands for chemoradiotherapy, chemotherapy combined with radiation. The surrounding treatment details make that meaning clear.