Related Experiment Video
Updated: Feb 19, 2026

Real-Time Cardiac Mapping with a Noninvasive Imageless Electrocardiographic Imaging System
Published on: April 11, 2025
Electrocardiographic patterns in biventricular pacing delivered by second-generation cardiac resynchronization
Amirfarjam Fazelifar1, Fatemeh Jorfi1, Majid Haghjoo1
1Cardiac Electrophysiology Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran; Department of Cardiac Electrophysiology, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran.
Biventricular (BiV) pacing, used in cardiac resynchronization therapy (CRT), commonly shows a dominant R wave in V1 and Q/q waves in leads I and aVL. These ECG patterns are typical and do not always indicate pacing issues.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Devices
Background:
- Cardiac resynchronization therapy (CRT) use is increasing.
- Familiarity with electrocardiogram (ECG) patterns during left ventricular (LV) and biventricular (BiV) pacing is crucial for physicians.
- Limited publications exist on ECG patterns during BiV pacing.
Purpose of the Study:
- To identify and characterize the diverse ECG patterns observed in patients undergoing BiV pacing.
- To provide a reference for interpreting ECGs in patients with BiV pacing.
Main Methods:
- Analysis of 12-lead ECGs from 181 patients with advanced heart failure and left bundle branch block.
- Patients had undergone at least 6 months of uncomplicated CRT with BiV pacing (RV apex and LV lateral coronary veins).
Main Results:
- A dominant R wave in lead V1 was observed in 65% of patients during BiV pacing.
- Right axis deviation (57%) or left superior axis (34%) was common in the frontal plane.
- A Q/q wave was present in leads I (85%) and aVL (78%).
- Sequential BiV pacing and pacing from posterolateral veins were associated with a dominant R wave in V1.
Conclusions:
- BiV pacing characteristically presents with a dominant R wave in V1, Q/q waves in leads I and aVL, and right or left superior axis.
- Absence of these specific findings (e.g., negative complex in V1, different QRS axis, no Q/q waves) does not automatically signify a problem with the pacing system.
More Related Videos
12:45Benefits of Cardiac Resynchronization Therapy in an Asynchronous Heart Failure Model Induced by Left Bundle Branch Ablation and Rapid Pacing
Published on: December 11, 2017
06:57Ablation of Ischemic Ventricular Tachycardia Using a Multipolar Catheter and 3-dimensional Mapping System for High-density Electro-anatomical Reconstruction
Published on: January 31, 2019
Related Concept Videos
Dysrhythmias IV: Characteristics of Bradyarrhythmias
Electrophysiology of Normal Cardiac Rhythm
ECG Interpretation of Arrhythmias II: Atrial, Junctional and Ventricular Arrhythmias
Dysrhythmias III: Characteristics of Dysrhythmias
Disturbances in Heart Rhythm
Arrhythmias are categorized by their speed, rhythm, and origin. A slow heart...
Dysrhythmias II: Classification of Tachyarrhythmias