Preface ix

Acknowledgments xiii

Part I: Building blocks of fibrillation 1

Excitation and propagation 1

Source-sink relationships 2

What determines source-sink balance? 3

Propagation and reentry 4

Requirements for reentry 4

What makes a circuit? 6

Source-sink balance and rotors 6

Wave length 8

Wave length, path length, and reentry 9

Restitution 10

Initiating reentry 11

Part II: Atrial fibrillation mechanisms 21

The evolution of current concepts 21

The mass hypothesis of atrial fibrillation 30

Principles of propagation: Implications for fibrillation 32

Focal rotors 52

Micröreentry 55

Fibrillatory conduction or multi¿wavelet reentry? 66

Location of atrial fibrillation drivers 76

Principles of propagation: Driver interactions in fibrillation 87

Part III: Working with incomplete information 93

Cardiac mapping 93

Sample density and atrial fibrillation 115

What should we do with the patient who comes to the lab tomorrow? Putting it all together (without "it all") 128

Putting it all together: Atrial fibrillation in three questions 132

Appendix A: Calculating probability in a random walk 135

Appendix B: Dominant frequency analysis 137

Appendix C: A stupid idea, but a learning opportunity 143

References 149

Index 161

Understanding Atrial Fibrillation