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Cardiac Electrophysiology Clinics Dec 2021Delayed atrioventricular (AV) conduction most commonly occurs in the AV node, resulting from AH prolongation on an intracardiac electrocardiogram and PR prolongation on... (Review)
Review
Delayed atrioventricular (AV) conduction most commonly occurs in the AV node, resulting from AH prolongation on an intracardiac electrocardiogram and PR prolongation on a surface electrocardiogram. AV conduction may be blocked in a 2:1 manner, with a normal PR interval and wide QRS suggesting infranodal disease, whereas a prolonged PR interval and narrow QRS are more suggestive of AV nodal disease. Block within the His is suspected when there is 2:1 AV block with normal PR and QRS intervals. Complete heart block occurs when the atrial rhythm is totally independent of a junctional or lower escape rhythm.
Topics: Atrioventricular Block; Atrioventricular Node; Electrocardiography; Humans
PubMed: 34689889
DOI: 10.1016/j.ccep.2021.07.001 -
Cardiac Electrophysiology Clinics Dec 2021The cardiac conduction system is formed of histologically and electrophysiologically distinct specialized tissues uniquely located in the human heart. Understanding the... (Review)
Review
The cardiac conduction system is formed of histologically and electrophysiologically distinct specialized tissues uniquely located in the human heart. Understanding the anatomy and pathology of the cardiac conduction system is imperative to an interventional electrophysiologist to perform safe ablation and device therapy for the management of cardiac arrhythmias and heart failure. The current review summarizes the normal and developmental anatomy of the cardiac conduction system, its variation in the normal heart and congenital anomalies, and its pathology and discusses important clinical pearls for the proceduralist.
Topics: Atrioventricular Node; Bundle of His; Heart Conduction System; Heart Failure; Humans
PubMed: 34689887
DOI: 10.1016/j.ccep.2021.06.003 -
Critical Care Nursing Clinics of North... Sep 2016In this article, the authors outline the key components behind the automated generation of the cardiac impulses and the effect these impulses have on cardiac myocytes.... (Review)
Review
In this article, the authors outline the key components behind the automated generation of the cardiac impulses and the effect these impulses have on cardiac myocytes. Also, a description of the key components of the normal cardiac conduction system is provided, including the sinoatrial node, the atrioventricular node, the His bundle, the bundle branches, and the Purkinje network. Finally, an outline of how each stage of the cardiac conduction system is represented on the electrocardiogram is described, allowing the reader of the electrocardiogram to translate background information about the normal cardiac conduction system to everyday clinical practice.
Topics: Atrioventricular Node; Bundle of His; Critical Care Nursing; Electrocardiography; Heart Conduction System; Heart Rate; Humans; Sinoatrial Node
PubMed: 27484656
DOI: 10.1016/j.cnc.2016.04.001 -
Cardiology Clinics Aug 2023Delayed atrioventricular (AV) conduction most commonly occurs in the AV node, resulting from AH prolongation on an intracardiac electrocardiogram and PR prolongation on... (Review)
Review
Delayed atrioventricular (AV) conduction most commonly occurs in the AV node, resulting from AH prolongation on an intracardiac electrocardiogram and PR prolongation on a surface electrocardiogram. AV conduction may be blocked in a 2:1 manner, with a normal PR interval and wide QRS suggesting infranodal disease, whereas a prolonged PR interval and narrow QRS are more suggestive of AV nodal disease. Block within the His is suspected when there is 2:1 AV block with normal PR and QRS intervals. Complete heart block occurs when the atrial rhythm is totally independent of a junctional or lower escape rhythm.
Topics: Humans; Atrioventricular Block; Atrioventricular Node; Electrocardiography; Heart Rate
PubMed: 37321683
DOI: 10.1016/j.ccl.2023.03.007 -
Circulation. Arrhythmia and... Jun 2017
Review
Topics: Arrhythmias, Cardiac; Atrioventricular Node; Bundle-Branch Block; Diagnosis, Differential; Humans; Tachycardia
PubMed: 28630176
DOI: 10.1161/CIRCEP.117.005481 -
Heart Failure Clinics Jan 2017Cardiac resynchronization therapy (CRT) is a device-based, nonpharmacologic approach that has shown to improve the outcome in patients with heart failure in terms of... (Review)
Review
Cardiac resynchronization therapy (CRT) is a device-based, nonpharmacologic approach that has shown to improve the outcome in patients with heart failure in terms of mortality and morbidity reduction. Large randomized trials have virtually enrolled patients in New York Heart Association class III-IV, with reduced left ventricular ejection fraction, with evidence of electrical dyssynchrony, and receiving optimal medical therapy and who were in sinus rhythm. Guidelines remain imprecise as to defining differentiated approaches according to the forms of atrial fibrillation other than permanent. These recommendations remain unsupported by evidence derived from randomized controlled trials, which are much needed.
Topics: Ablation Techniques; Atrial Fibrillation; Atrioventricular Node; Cardiac Resynchronization Therapy; Cardiac Resynchronization Therapy Devices; Combined Modality Therapy; Comorbidity; Evidence-Based Medicine; Heart Failure; Humans; Practice Guidelines as Topic; Randomized Controlled Trials as Topic; Survival Rate; Treatment Outcome
PubMed: 27886923
DOI: 10.1016/j.hfc.2016.07.015 -
Cardiac Electrophysiology Clinics Dec 2015Cardiac resynchronization therapy (CRT) is a device-based, nonpharmacologic approach that has shown to improve the outcome in patients with heart failure in terms of... (Review)
Review
Cardiac resynchronization therapy (CRT) is a device-based, nonpharmacologic approach that has shown to improve the outcome in patients with heart failure in terms of mortality and morbidity reduction. Large randomized trials have virtually enrolled patients in New York Heart Association class III-IV, with reduced left ventricular ejection fraction, with evidence of electrical dyssynchrony, and receiving optimal medical therapy and who were in sinus rhythm. Guidelines remain imprecise as to defining differentiated approaches according to the forms of atrial fibrillation other than permanent. These recommendations remain unsupported by evidence derived from randomized controlled trials, which are much needed.
Topics: Anti-Arrhythmia Agents; Atrial Fibrillation; Atrioventricular Node; Cardiac Resynchronization Therapy; Combined Modality Therapy; Comorbidity; Evidence-Based Medicine; Heart Failure; Humans; Prevalence; Risk Factors; Survival Rate; Treatment Outcome
PubMed: 26596816
DOI: 10.1016/j.ccep.2015.08.006 -
Cardiology Clinics Aug 2023Atrioventricular (AV) nodal conduction is decremental and very prone to alterations in autonomic tone. Conduction through the His-Purkinje system (HPS) is via fast... (Review)
Review
Atrioventricular (AV) nodal conduction is decremental and very prone to alterations in autonomic tone. Conduction through the His-Purkinje system (HPS) is via fast channel tissue and typically not that dependent on autonomic perturbations. Applying these principles, when the sinus rate is stable and then heart block suddenly occurs preceded by even a subtle slowing of heart rate, it typically is caused by increased vagal tone, and block occurs in the AV node. Heart block with activity strongly suggests block in the HPS. Enhanced sympathetic tone and reduced vagal tone can facilitate induction of both AV and atrioventricular node reentry.
Topics: Humans; Heart Rate; Atrioventricular Node; Heart Block; Electrocardiography
PubMed: 37321682
DOI: 10.1016/j.ccl.2023.03.015 -
Cardiac Electrophysiology Clinics Dec 2021Atrioventricular (AV) nodal conduction is decremental and very prone to alterations in autonomic tone. Conduction through the His-Purkinje system (HPS) is via fast... (Review)
Review
Atrioventricular (AV) nodal conduction is decremental and very prone to alterations in autonomic tone. Conduction through the His-Purkinje system (HPS) is via fast channel tissue and typically not that dependent on autonomic perturbations. Applying these principles, when the sinus rate is stable and then heart block suddenly occurs preceded by even a subtle slowing of heart rate, it typically is caused by increased vagal tone, and block occurs in the AV node. Heart block with activity strongly suggests block in the HPS. Enhanced sympathetic tone and reduced vagal tone can facilitate induction of both AV and atrioventricular node reentry.
Topics: Atrioventricular Node; Autonomic Nervous System; Heart Block; Heart Rate; Humans
PubMed: 34689888
DOI: 10.1016/j.ccep.2021.06.004 -
Cardiac Electrophysiology Clinics Jun 2018This article describes the different anatomic structures involved in normal atrioventricular conduction and their pathologic states. It defines their effects on the... (Review)
Review
This article describes the different anatomic structures involved in normal atrioventricular conduction and their pathologic states. It defines their effects on the electrocardiogram, and describes how to localize the level and evaluate the severity of conduction disease by electrocardiographic analysis. It illustrates the relevance of intracavitary recordings in the diagnosis of level of block.
Topics: Atrioventricular Node; Electrocardiography; Heart Rate; Humans; Tachycardia, Atrioventricular Nodal Reentry
PubMed: 29784480
DOI: 10.1016/j.ccep.2018.02.014