Related Experiment Video

Updated: Sep 27, 2026

Benefits of Cardiac Resynchronization Therapy in an Asynchronous Heart Failure Model Induced by Left Bundle Branch Ablation and Rapid Pacing
12:45

Benefits of Cardiac Resynchronization Therapy in an Asynchronous Heart Failure Model Induced by Left Bundle Branch Ablation and Rapid Pacing

Published on: December 11, 2017

Usefulness of electrocardiographic QRS/T angles with versus without bundle branch blocks to predict heart failure

Zhu-ming Zhang1, Pentti M Rautaharju1, Ronald J Prineas1

  • 1Epidemiological Cardiology Research Center (EPICARE), Department of Epidemiology and Prevention, Division of Public Health Sciences, Wake Forest School of Medicine, Winston-Salem, North Carolina.

The American Journal of Cardiology
|June 16, 2014
PubMed

Insights

Bundle branch blocks (BBB) and wide QRS/T angles significantly increase heart failure risk. Their combined presence poses a threefold higher risk, indicating repolarization abnormalities in BBB are not benign.

Area of Science:

  • Cardiology
  • Electrocardiography
  • Heart Failure Prediction

Background:

  • Repolarization abnormalities are often overlooked in patients with bundle branch blocks (BBB).
  • The prognostic significance of combining BBB with wide QRS/T angles for heart failure (HF) risk is not well-established.

Purpose of the Study:

  • To investigate the association between wide spatial and frontal QRS/T angles and incident heart failure (HF) in individuals with and without bundle branch blocks (BBB).
  • To determine if the combined presence of BBB and wide QRS/T angles amplifies HF risk.

Main Methods:

  • Cox regression models were used to analyze data from 14,478 participants in the Atherosclerosis Risk in Communities Study, free of HF at baseline.
  • Participants were categorized based on the presence of BBB and wide spatial/frontal QRS/T angles (upper 25th percentile).
  • Multivariable adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated.

Main Results:

  • Wide spatial QRS/T angle increased HF risk by 51% in those without BBB (HR 1.51).
  • BBB alone increased HF risk by 48% (HR 1.48).
  • The combination of BBB and wide spatial QRS/T angle elevated HF risk more than threefold (HR 3.37).
  • Similar findings were observed for the frontal plane QRS/T angle and across gender subgroups.
  • In pooled BBB, a positive T wave in aVR and heart rate ≥70 bpm also predicted incident HF.

Conclusions:

  • Both bundle branch blocks (BBB) and wide QRS/T angles are independent predictors of incident heart failure (HF).
  • The co-occurrence of BBB and wide QRS/T angles significantly magnifies HF risk.
  • Repolarization abnormalities in the context of BBB should not be dismissed as benign or merely a consequence of the block.

More Related Videos

Real-Time Cardiac Mapping with a Noninvasive Imageless Electrocardiographic Imaging System10:17

Real-Time Cardiac Mapping with a Noninvasive Imageless Electrocardiographic Imaging System

Published on: April 11, 2025

Cutoff Value of Phase Angle by Bioelectrical Impedance Analysis at Admission as a Prognostic Factor in Patients with Acute Heart Failure05:16

Cutoff Value of Phase Angle by Bioelectrical Impedance Analysis at Admission as a Prognostic Factor in Patients with Acute Heart Failure

Published on: June 10, 2025

Related Concept Videos

Electrocardiogram01:29

Electrocardiogram

An electrocardiogram (ECG or EKG) is a critical diagnostic tool that records the electrical signals produced by the heart during each heartbeat. This recording is achieved through electrodes placed strategically on the arms, legs, and chest. The electrocardiograph amplifies these signals and produces 12 distinct tracings, offering a comprehensive understanding of the heart's electrical activity.
Three major waveforms are present in a typical ECG recording: the P wave, the QRS complex, and the T...
Disturbances in Heart Rhythm01:29

Disturbances in Heart Rhythm

Arrhythmia or dysrhythmia refers to an abnormal heart rhythm caused by a defect in the heart's conduction system. It can cause the heart to beat irregularly, too quickly, or too slowly, leading to symptoms like chest pain, shortness of breath, and fainting. Factors such as stress, caffeine, alcohol, nicotine, cocaine, certain drugs, congenital defects, diseases, and electrolyte abnormalities can trigger arrhythmias.
Arrhythmias are categorized by their speed, rhythm, and origin. A slow heart...
Electrocardiogram Fundamentals01:28

Electrocardiogram Fundamentals

Introduction
An electrocardiogram (ECG) is a diagnostic tool for identifying cardiac conditions such as arrhythmias, conduction abnormalities, and myocardial ischemia.
Definition
An electrocardiogram (ECG) visualizes the heart's electrical activity by tracing the electrical movement associated with each heartbeat on a graph or monitor. As the heart beats, an electrical wave passes through it, correlating with the cardiac cycle events.
Parts of an ECG
An ECG utilizes electrodes on the skin to...
Acute Coronary Syndrome III: Diagnostic Studies01:30

Acute Coronary Syndrome III: Diagnostic Studies

Diagnosing acute coronary syndrome or ACS begins with a thorough patient history. Notable symptoms include central, crushing chest pain radiating to the left arm, neck, jaw, or back, along with shortness of breath, sweating (diaphoresis), nausea, vomiting, dizziness, and palpitations.It is crucial to note any history of cardiac illnesses and assess risk factors, including age, gender, smoking, hypertension, diabetes, hyperlipidemia, and a sedentary lifestyle.During physical examination, vital...
Dysrhythmias IV: Characteristics of Bradyarrhythmias01:18

Dysrhythmias IV: Characteristics of Bradyarrhythmias

Bradyarrhythmias are cardiac rhythm disorders characterized by a slower-than-normal heart rate, typically defined as fewer than 60 beats per minute. Some of which are discussed here:Sinus BradycardiaSinus bradycardia presents a heart rate lower than 60 beats per minute, with a regular rhythm originating from the SA node. The ECG typically shows normal P waves preceding each QRS complex, a normal PR interval (0.12 to 0.20 seconds), and a normal QRS duration (0.06 to 0.10 seconds).First-Degree AV...
Dysrhythmias V: Evaluating Dysrhythmias01:30

Dysrhythmias V: Evaluating Dysrhythmias

Dysrhythmias, also known as arrhythmias, are disturbances in the heart's rhythm that range from benign to life-threatening. A thorough evaluation is crucial for appropriate management and involves a comprehensive medical history, physical examination, and various diagnostic tests.Medical HistorySymptoms: Collect detailed information on palpitations, dizziness, syncope, chest pain, and fatigue. Note their onset, frequency, and triggers.Previous Cardiac Issues: Document any history of heart...