Electrophysiology 101: What Do Surgeons Need to Know. Richard B Schuessler PhD

Transcription

1 Electrophysiology 101: What Do Surgeons Need to Know Richard B Schuessler PhD

2 Disclosures Research Grant from Atricure, Inc.

3 Arrhythmias Where The Surgical Approach Has Been Used WPW AVNRT Automatic Ectopic Atrial Tachycardias Inappropriate Sinus Tachycardia Atrial flutter/fibrillation Ischemic and Non-ischemic VT ARVD Tachycardia Congenital Post Repair Arrhythmias (i.e. flutter following the Fontan procedure)

4 Factors Common to All Arrhythmias 1. Abnormal Impulse Formation Number Timing 2. Velocity of propagation Magnitude Anisotropy 3. Refractory period Magnitude Homogeneity 4. Anatomic Geometry Macroscopic Microscopic Each of these factors are dynamic. They remodel with pathology (i.e. MR) and AF.

5 Arrhythmia Mechanisms Non Reentrant Reentrant

6 Arrhythmia Mechanisms Spiral Wave Reentry (rotors) Kneller et al Circ Res. 2002;90:e73-e87.

7 Nishida et al Circ Res:214:

8 Abnormal Impulse Formation: PACs 24-hour Holter electrocardiograms to assess PAC prevalence and frequency were performed in a random sample of 1742 (Swiss) participants aged >50 years. PACs are common, and their frequency is independently associated with age, height, history of cardiovascular disease, natriuretic peptide levels, physical activity, and high-density lipoprotein cholesterol. David Conen, et al. Premature Atrial Contractions in the General Population: Frequency and Risk Factors Circulation.2012;126:

9 Remodeling of Refractory Period Increased rate, with AF, cause the action potential and refractory period to decrease. This makes it easier for AF to be maintained (shorter wave length). This is why AF begets AF. Many other pathologies alter refractory Period. For example, heart failure prolongs refractory period.

10 Remodeling Conduction: Increased Fibrosis Increased fibrosis slows and blocks conduction. Yonjun Q et al:cardiovascular Pathology 22 (2013)

11 Remodeling Conduction: Fibrosis Hansen BJ et al: J Am Coll Cardiol EP 2017;3:531 46

12 Anatomy: Complexity

13 Anatomy: Size Matters Damiano RJ et al. J Thorac Cardiovasc Surg 2011;141:113-21

14 Subdivision of Atria in an Intact Pig Lesions are created using a bipolar RF clamp Lee AM et al. J Thorac Cardiovasc Surg 2013;146:593-8

15 Probability of AF vs. ERP vs. Area 1.0 ERP=50 Prob [AF] ERP=75 ERP=100 ERP=125 AUC is ERP p= Area p= ERP=150 ERP=175 ERP=200 ERP=225 ERP= Atrial Surface Area (mm**2) Lee AM et al. J Thorac Cardiovasc Surg 2013;146:593-8

16 History of AF Mechanisms Engelman (1895) Multiple Foci Rothberger &Winterberg (1914) Single Rapid Focus Garrey (1914) Reentry In A Critical Mass Lewis (1921) Single Reentrant Circuit With Fibrillatory Conduction Scherf (1947) Single Rapid Focus (Aconitine) Moe (1962) Multiple Wavelet Hypothesis Allessie (1984) Multiple Wavelets Cox (1991) Multiple Changing Mechanisms- Macro Reentrant Circuit, Focal Activation, Spiral Rotor Haissaguerre (1998) Focal PV Source Narayan (2012) 1-2 Stable Rotors Or Focal Sources Federov(2015) Micro Anatomic Reentry Allessie (2016) Multiple Wavelets with Epi-Endo discordance

17 Atrial Fibrillation There is a great deal of controversy at the moment over the underlying activation patterns that cause AF.

18 Mechanisms of Atrial Fibrillation

19 Intraopertive Mapping of Human AF -Macro reentrant circuit -Small rotor -Focal activation pattern -Pattern changed over time Cox JL, et al. The Surgical Treatment of Atrial Fibrillation. JTCVS, March 1991.

20 ECGI Activation Mapping - Long Standing Persistent AF Cuculich P et al: Circulation. 2010;122:

21 The Time Course And Evolution Of AF Jordi Heijman et al. Circ Res. 2014;114:

22 Progression From Paroxysmal to Persistent Atrial Fibrillation Clinical Correlates and Prognosis included 1,219 patients with paroxysmal AF who participated in the Euro Heart Survey on AF and had a known rhythm status at follow-up. Patients who experienced AF progression after 1 year of follow-up were identified. Cees B. de Vos, MD, et al: J Am Coll Cardiol 2010;55:

23 Progression to chronic atrial fibrillation after the initial diagnosis of paroxysmal atrial fibrillation: Results from the Canadian Registry of Atrial Fibrillation Charles R. Kerr et al: Am Heart J 2005;149:

24 Progression of paroxysmal atrial fibrillation to persistent atrial fibrillation in patients with bradyarrhythmias Sanjeev Saksena, MD, FHRS, FESC, FACC,a Douglas A. Hettrick, PhD,b Jodi L. Koehler, MS,b Andrea Grammatico, BS,b and Luigi Padeletti, MDc Am Heart J 2007;154:

25 The Prevalence of Sinus Rhythm in Patients with Permanent Atrial Fibrillation PAUL D. ZIEGLER, et al: PACE 2014 :1 8

26 Why the Maze Works Focal (Abnormal Automaticity, EAD, DAD) Micro [<1 cm] Reentrant Rotor Fixed Spiral(s) Micro Reentrant Rotor Meandering Spiral(s) Macro Reentrant Rotor Around Fixed Obstacle Macro Reentrant Meandering Rotor Multiple Wavelet The good news is that the Cox Maze procedure does not depend on any one mechanism. By using an anatomic approach we do not need to determine a specific mechanism to direct the treatment.

27 The Future Atrial DE MRI ECGI Marrouche NF et al: JAMA February 5, 2014 Volume 311, Number 5 Zahid S et al: Cardiovascular Research (2016) 110,