Understanding Clinical Cardiac Electrophysiology E-Book

Peter Spector

• Herausgeber: John Wiley & Sons
• Kategorie: Fachliteratur
• Sprache: Englisch

Seitenzahl: 331

Veröffentlichungsjahr: 2016

Beschreibung

In the fast paced world of clinical training, students are often inundated with the what of electrophysiology without the why. This new text is designed to tell the story of electrophysiology so that the seemingly disparate myriad observations of clinical practice come into focus as a cohesive and predictable whole.

• Presents a unique, conceptually-guided approach to understanding the movement of electrical current through the heart, the impact of various disease states and the positive effect of treatment
• Reviews electrophysiologic principles and the analytic tools which, when combined with a firm grasp of EP mechanisms, allow the reader to think through any situation
• Presents the mathematics necessary for the practice of cardiac electrophysiology in an accessible and understandable manner
• Contains accompanying video clips, including computer simulations showing the flow of electrical current through the heart, which help explain and visualise concepts discussed in the text
• Includes helpful chapter summaries and full color illustrations aid comprehension

Leseprobe

Table of Contents

Cover

Title Page

Preface

Why this book?

Cardiac electrophysiology as a “complex non-linear system”

“The heart is a computer”

What this book isn’t

Acknowledgments

About the companion website and enhanced edition

PART I: Third-person omniscient (how we would see EP if we could see EP)

1 Ion channels

How does a cell become electrically active?

Summary

2 Action potentials

Action potential phases

The connection between ion channel physiology and tissue behavior

Clinical correlation

Summary

3 Propagation

Summary

4 Arrhythmia mechanisms

Automaticity

Triggered firing

Reentry

Atrial fibrillation: a case study in reentry

Summary

5 Anatomy for electrophysiologists

A tour of cardiac anatomy

Right atrium

Right ventricle

Left atrium – pulmonary vein

Left atrium

Coronary sinus

Left ventricle

Left meets right

Summary

PART II: Doctor’s-eye view (dealing with incomplete knowledge)

6 Deducing anatomy

Using imaging to navigate the heart

Fluoroscopy

Trans-septal catheterization

Summary

7 Electrical activity, electrodes, and electrograms

Intracardiac recording and spatial resolution

Recording configuration and spatial resolution

Orthogonal close unipolar

Quantifying spatial resolution

Calculating electrical activity from electrograms

Spatial resolution and electrogram fractionation

Tissue activation patterns and electrograms

Summary

8 Electrogram analysis: understanding electrogram morphology

Electrograms vs. EKGs

Electrograms

Unipolar electrograms

Bipolar electrograms

Discerning earliest activation

General considerations

Summary

9 Differential diagnostic pacing maneuvers

Differential diagnosis of narrow complex tachycardia

Mapping accessory pathways

Para-Hisian pacing

Para-Hisian pacing 201

Entrainment

Summary

10 Electro-anatomic mapping

Activation mapping

Substrate mapping

Putting it all together: a case

Summary

Appendix: What we measure when we record an electrogram

Electricity and the electric field

Coulomb’s law

The electric potential field

Ohm’s law

Recording the intracardiac electrogram

Afterword: Your heart is a computer: from army ants to atrial fibrillation

Suggested reading

Index

End User License Agreement

List of Illustrations

Chapter 01

Figure 1.1

Lipid bilayer.

Charged ions cannot cross the cell membrane; they are repelled by the hydrophobic lipid “tails.”

Figure 1.2

Creation of an ion concentration gradient.

(Top) Without the sodium potassium pump (Na

+

K

+

ATPase) there is equal distribution of ions on both sides of the membrane (represented by the horizontal lines). (Middle and bottom) Na

+

K

+

ATPase moves Na

+

ions out of, and K

+

ions into, the cell, establishing concentration gradients for both of these ions.

Figure 1.3

Electrochemical gradient.

(Top) Once I

K1

channels open, allowing K

+

to move across the membrane, the K

+

concentration gradient pulls K

+

out of

the cell. (Bottom) As K

+

leaves the cell (without any anions) a voltage gradient begins to develop; this exerts an

inward

force on K

+

, reducing the net outward force. K

+

will continue to flow down its concentration gradient until the voltage gradient exactly offsets the concentration gradient; this voltage is called the equilibrium potential (there is no longer any

net

flow of K

+

).

Figure 1.4

Sodium channel

gating.

(Top left) In the resting state sodium channels are closed and their inactivation gate is open (“recovered from inactivation”). (Top right) If the membrane is depolarized to threshold the voltage sensor moves, causing a conformational change in the channel which opens the pore (activation). Because activation gating is faster than inactivation, at this point the inactivation gate remains open and sodium can enter the cell. (Bottom left) After a few milliseconds the inactivation gate closes. (Bottom right) As the membrane repolarizes the activation gate closes. With further repolarization the inactivation gate “recovers from inactivation” (opens) and the cell is prepared for the next action potential (top left).