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AV and VV delay optimization

An ICD & CRT Therapy term on the RCES exam blueprint, defined for cath lab and EP clinicians.

AV delay is tuned so atrial-sensed or paced activity is followed by ventricular pacing at a timing that maximizes diastolic filling without causing fusion with the patient's own conduction; VV delay (the timing offset between right and left ventricular lead pacing) is tuned to maximize mechanical synchrony between the two ventricles. The overarching practical goal across both is maximizing the percentage of time the patient is actually being biventricularly paced, since CRT benefit is closely tied to a high percentage (generally >98%) of effective biventricular pacing.

Domain: ICD & CRT Therapy · Blueprint: RCES exam guide

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Written and reviewed by John-Philip (JP) Maarschalk, BSN, RN, CNML — a nurse manager who runs operations for the cardiac cath lab, electrophysiology, and interventional service lines at an academic health system in North Carolina. He hires and develops the staff who sit for these exams. More about JP and how this content is made →
Cardiac Codex is an independent study tool published by MdoubleA LLC, not affiliated with or endorsed by CCI or any certifying body. This glossary entry is exam-preparation information, not medical advice or a substitute for clinical judgment. Always verify current clinical practice against primary sources and institutional protocol.