Sinoatrial arrest pathophysiology

Revision as of 15:55, 4 February 2013 by Aarti Narayan (talk | contribs)
Jump to navigation Jump to search

Sinoatrial arrest Microchapters

Home

Patient Information

Overview

Historical Perspective

Pathophysiology

Causes

Differentiating Sinoatrial arrest from other Diseases

Epidemiology and Demographics

Risk Factors

Natural History, Complications and Prognosis

Diagnosis

History and Symptoms

Physical Examination

Laboratory Findings

Electrocardiogram

Chest X Ray

Echocardiography

Other Imaging Findings

Other Diagnostic Studies

Treatment

Medical Therapy

Surgery

Primary Prevention

Secondary Prevention

Cost-Effectiveness of Therapy

Future or Investigational Therapies

Case Studies

Case #1

Sinoatrial arrest pathophysiology On the Web

Most recent articles

Most cited articles

Review articles

CME Programs

Powerpoint slides

Images

American Roentgen Ray Society Images of Sinoatrial arrest pathophysiology

All Images
X-rays
Echo & Ultrasound
CT Images
MRI

Ongoing Trials at Clinical Trials.gov

US National Guidelines Clearinghouse

NICE Guidance

FDA on Sinoatrial arrest pathophysiology

CDC on Sinoatrial arrest pathophysiology

Sinoatrial arrest pathophysiology in the news

Blogs on Sinoatrial arrest pathophysiology

Directions to Hospitals Treating Sinoatrial arrest

Risk calculators and risk factors for Sinoatrial arrest pathophysiology

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

In this disorder, the sinoatrial node is generating electrical complexes, but the electrical activity fails to conduct in the atrium. Sinoatrial automaticity is preserved, and the P waves are generated at a regular rate in a regular pattern which are a multiple of the basic sinus cycle. In patients with sinus exit block, the block is more frequently associated with either an atrial or an AV junctional escape rhythm.

Pathophysiology

First degree SA exit block

There is a conduction delay (a slowing of conduction not a block or completion cessation in electrical conduction) in the impulse traveling from the sinus node to the atrium and there are no discernible changes on the surface EKG.

Second Degree SA exit block

This condition refers to intermittent conduction block (not a delay or slowing of conduction but a completion cessation of conduction) between the sinus node and the atrium.

Type I (Wenckebach phenomenon) sinoatrial exit block

This is an example of group beating. The P-P cycle (time between two P waves) is progressively shortened until there is a pause. This pause is less than twice the shortest P-P interval. The cycle is then repeated. The pause is due to the dropped P wave and measures less than twice the P-P cycle. It is similar to the behavior of the RR intervals in type I second-degree AV block.

Type II second-degree sinoatrial exit block

There is an unexpected drop of the P wave. Following this drop, there is a pause in the sinus cycle which is a multiple of the basic sinus cycle. Blocked atrial premature beats sometimes mimic second-degree sinoatrial block.

Third-degree sinoatrial exit block

This SA block cannot be distinguished from sinus arrest when the sinus node ceases to fire. Under such circumstances, subsidiary pacemakers in the AV junction or ventricles may take over.

References

Template:WH Template:WS