Paradigms in Atrial Fibrillation Sunthosh V. Parvathaneni, MD, - - PowerPoint PPT Presentation

Paradigms in Atrial Fibrillation

Sunthosh V. Parvathaneni, MD, FACC, FHRS

Clinical Cardiac Electrophysiology Assistant Professor in Clinical Medicine, University of Missouri School of Medicine Mercy Hospital Springfield

Objectives

To understand the Clinical Considerations of the Physician

Assistant when dealing with Atrial Fibrillation

To understand the Mechanisms and Causes of Atrial

Fibrillation

To learn to visualize Significant Anatomy relevant to Atrial

Fibrillation

To discuss Tools and Techniques relevant to treating Atrial

Fibrillation

Clinical Considerations

• Epidemiology
• Atrial fibrillation (AF) is the most

common clinically significant cardiac arrhythmia in the world.

• Approximately one third of

hospitalizations for cardiac rhythm disturbance

• 2.3 million people in the United

States and 4.5 million in the European Union have paroxysmal or persistent AF

• Hospital admissions for AF have

increased by 66% due to the aging population

Issa, Z.F ., Miller, J.M., & Zipes, D.P . (2009). Atrial Fibrillation. In Z.F . Issa, J.M. Miller & D.P . Zipes, Clinical Arrhythmology and Electrophysiology (208-284). Philadelphia: Saunders Elsevier

Clinical Considerations

• Epidemiology
• AF is associated with an increased long-

term risk of stroke, heart failure, and all- cause mortality, especially in women

• The mortality rate of patients with AF is

approximately double that of patients in sinus rhythm and is linked to the severity

• f underlying heart disease
• The most devastating consequence of AF

is stroke as a result of thromboembolism

• 1 out of every 6 strokes occurs in patients

with AF

ACCF/AHA Pocket Guideline. Management of Patients with Atrial

• Fibrillation. Adapted from the 2006 ACC/AHA/ESC Guidline and the 2011

ACCF/AHA/HRS Focused Updates)

Clinical Considerations

ACCF/AHA Pocket Guideline. Management of Patients with Atrial

• Fibrillation. Adapted from the 2006 ACC/AHA/ESC Guideline and the

2011 ACCF/AHA/HRS Focused Updates)

• Risk Stratification
• CHADS2 VASc Score
• Prior Stroke/TIA (2 points)
• Age > 65 and < 74 (1 point)
• Hypertension (1 point)
• Diabetes Mellitus (1 point)
• Heart failure (1 point)
• Vascular Disease (1 point)
• Prior MI, PAD, Aortic Plaque
• Age > 75 (2 points)
• Female Sex ( 1 point)

Clinical Considerations

Anticoagulation If CHADS2-Vasc < 2, discussion with the patient should be had whether

they would be content with ASA alone or anticoagulation with Coumadin

• r DOAC (Direct Oral Anticoagulation)

If CHADS2-VASc > 2, anticoagulation is preferred with either Coumadin or

DOAC (Pradaxa, Eliquis, Xarelto, etc.). They have been shown to be superior in reduction of both ischemic and hemorrhage stroke and bleeding

Pradaxa has a sight increase in evidence of GI bleeding compared to Coumadin Pradaxa does offer a reversal agent that can reverse in less than 1 second ACCF/AHA Pocket Guideline. Management of Patients with Atrial Fibrillation. Adapted from the 2006 ACC/AHA/ESC Guidline and the 2011 ACCF/AHA/HRS Focused Updates)

Clinical Considerations

• Clinical Presentation
• Symptomatic or asymptomatic, even in the

same patient

• up to 21% of newly diagnosed patients with

AF are asymptomatic

• Symptoms associated with AF vary with:
• ventricular rate
• underlying functional status
• duration of AF
• presence and degree of structural heart

disease

• individual patient perception
• Most patients with AF complain of

palpitations, angina, dyspnea, fatigue, or dizziness

Issa, Z.F ., Miller, J.M., & Zipes, D.P . (2009). Atrial Fibrillation. In Z.F . Issa, J.M. Miller & D.P . Zipes, Clinical Arrhythmology and Electrophysiology (208-284). Philadelphia: Saunders Elsevier

Clinical Presentation

• Initial Evaluation
• Characterize the pattern of the arrhythmia
• How long have they had it?
• How long have they experienced symptoms?
• Cardioversions in the past?
• What drugs are are they on (prescription, OTC,

recreational)?

• Determine underlying causes (heart failure, pulmonary

problems, hypertension, or hyperthyroidism)

• Define associated cardiac and extracardiac conditions

Classification of Atrial Fibrillation

AF

First detected episode Recurrent (After 2 episodes) Paroxysmal (self- terminates) Persistent 7days – 1 year Permanent (Cardioversion failed)

ACCF/AHA Pocket Guideline. Management

• f Patients with Atrial Fibrillation. Adapted

from the 2006 ACC/AHA/ESC Guidline and the 2011 ACCF/AHA/HRS Focused Updates

Clinical Presentation

• Patient Management
• Four Main Issues that must be addressed

1. Prevention of systemic embolization (clot) 2. Rate control 3. Rhythm control 4. Choosing between rhythm and rate control

• Choice of therapy is influenced by:
• Patient preference
• Associated structural heart disease
• Severity of symptoms
• Whether the AF is recurrent paroxysmal, recurrent persistent, or

permanent (chronic)

• In addition, patient education is critical, given the potential

morbidity associated with AF and its treatment.

Electrocardiographic Features

• Characterized by rapid and

irregular atrial fibrillatory waves (f waves) and lack of clearly defined P waves

• Best seen Lead V1 and in

the inferior leads (II, III, and AVF).

• Rate of the fibrillatory waves --

between 350 and 600 beats/min

• The atrium is in a state of chaos
• Ventricular response is typically

irregularly irregular

Issa, Z.F ., Miller, J.M., & Zipes, D.P . (2009). Atrial Fibrillation. In Z.F . Issa, J.M. Miller & D.P . Zipes, Clinical Arrhythmology and Electrophysiology (208-284). Philadelphia: Saunders Elsevier

Mechanisms

• Two concepts of the underlying mechanism of AF have received

considerable attention:

1. Factors that trigger the onset of AF 2. Factors that perpetuate AF

• Patients with frequent, self-terminating episodes of AF are likely to

have a predominance of factors that trigger AF

• Patients with AF that does not terminate spontaneously are more

likely to have a predominance of factors that perpetuate AF

• This generalization has clinical usefulness, but there is considerable
• verlap of these mechanisms in the typical AF patient

Issa, Z.F ., Miller, J.M., & Zipes, D.P . (2009). Atrial Fibrillation. In Z.F . Issa, J.M. Miller & D.P . Zipes, Clinical Arrhythmology and Electrophysiology (208-284). Philadelphia: Saunders Elsevier

Mechanisms of Initiation

• Stable focus (PAC) or reentrant

circuit with activation arising from this focus too rapid to be conducted uniformly throughout the atria

• Rapid propagation of the wave

fronts breaks up into irregular wavelets

• Mechanism of initiation of AF is

not certain in most cases and likely is multifactorial

Issa, Z.F ., Miller, J.M., & Zipes, D.P . (2009). Atrial

• Fibrillation. In Z.F

. Issa, J.M. Miller & D.P . Zipes, Clinical Arrhythmology and Electrophysiology (208-284). Philadelphia: Saunders Elsevier Murgatroyd, F .D., Krahn, A.D., Klein, G.J., Yee, R.K, & Skanes, A..C(2001). Atrial Arrhythmias. In Murgatroyd, F .D., Krahn, A.D., Klein, G.J., Yee, R.K, & Skanes, Handbook of Cardiac Electrophysiology (55-71). London: ReMEDICA Publishing Limited

Mechanisms of Initiation

• AF Triggers
• Premature Atrial Complexes (PACs)

from the Pulmonary Veins (PVs), Coronary Sinus (CS), Superior Vena Cava (SVC), Ligament of Marshall, Left Atrial chamber, RA chamber (crista terminalis)

• Sympathetic or Parasympathetic

stimulation

• Other Supraventricular Tachycardia

(SVT)

• AVRT

, AFL, AVNRT

• Identification and treatment of

triggers may be curative

Issa, Z.F ., Miller, J.M., & Zipes, D.P . (2009). Atrial Fibrillation. In Z.F . Issa, J.M. Miller & D.P . Zipes, Clinical Arrhythmology and Electrophysiology (208-284). Philadelphia: Saunders Elsevier

Mechanisms of Initiation

• Triggering foci of rapidly firing

cells within the sleeves of atrial myocytes extending into the PVs have been clearly shown to be the underlying mechanism of most paroxysmal AF

• Thoracic veins are highly

arrhythmogenic

• PV-LA Junction has discontinuous

myocardial fibers separated by fibrotic tissues and, therefore, is highly anisotropic

Nathan, H., et al. “The Junction Between the Left Atrium and the Pulmonary Veins: An Anatomic Study of Human Hearts.” Circ, Vol. 34, (1966): 412-422. Print.

Mechanisms of Perpetuation

• Multiple wavelets of depolarization

propagate within the atria.

• These can divide, coalesce extinguish

each other as they travel in an apparently random fashion, seeking tissue that is excitable.

• Results in electrical and structural

remodeling

• Atrial Dilation
• Decreased Atrial Refractoriness
• Larger Hearts Fibrillate Easily (Elephant

and Whale)

• Smaller Hearts Do Not Fibrillate Easily

(Mice)

Murgatroyd, F .D., Krahn, A.D., Klein, G.J., Yee, R.K, & Skanes, A..C(2001). Atrial

• Arrhythmias. In Murgatroyd, F

.D., Krahn, A.D., Klein, G.J., Yee, R.K, & Skanes, Handbook of Cardiac Electrophysiology (55-71). London: ReMEDICA Publishing Limited Issa, Z.F ., Miller, J.M., & Zipes, D.P . (2009). Atrial Fibrillation. In Z.F . Issa, J.M. Miller & D.P . Zipes, Clinical Arrhythmology and Electrophysiology (208-284). Philadelphia: Saunders Elsevier

Tools and Techniques

Rate Control May be attained with calcium channel

blockers, beta blockers, or digoxin in those with normal EF

Calcium channel blockers must be used

cautiously in those with a low EF

Shown to have increased mortality long

term

Class IIb indication for rate control

Tools and Techniques

• Rhythm control

Pursued in those who are symptomatic despite

adequate rate control

Maintenance of sinus rhythm is similar between

the spectrum of antiarrhythmic drug medications (50 - 67% in 1 year)

Class Ic – Flecainide, Propafenone (avoid in CAD) Class III – Sotalol, Dronederone, Dofetilide, and

Amiodarone Recurrence of atrial fibrillation is 80% without

medical intervention

If considering this treatment arm, place a

referral to Cardiology

Tools and Techniques

• Invasive Cardiac Ablation
• Elimination of Triggers
• Pulmonary Vein Triggers
• Segmental Ostial Pulmonary

Vein Isolation

• Circumferential Antral

Pulmonary Vein Isolation

• Substrate Modification
• Wide Area Circumferential

(WACA)

• Linear Atrial Method
• Complex Fractionated Atrial

Electrogram (CFAE)

• Central Nervous System Denervation
• Non-Pulmonary Vein Triggers
• SVC and IVC Ablation
• Posterior Left Atrial Wall Ablation
• Management of Obstructive Sleep Apnea

Pulmonary Vein Isolation/Ablation

Medtronic Academy. Arctic Front Advance PVI Procedure. https://www.medtronicacademy.com/node/1604

Tools and Techniques

Timing of medical and invasive ablative

procedures is everything!

Success of being AF free for 1 year with

PVI is 80-90% in those with Paroxysmal Atrial Fibrillation

Success is dramatically reduced for those

with Persistent Atrial Fibrillation or Permanent Atrial Fibrillation ( < 50-60% AF free at 1 year)

Early management is the KEY to success There is currently no cure for AF in the

marketplace; just therapies to reduce episodes of AF

Summary

Atrial fibrillation is the most common arrhythmia in the

world

Prevalence continues to grow CHADS2-VASc is a pneumonic that can be used to risk

stratify need for anticoagulation for patients with AF

Management of AF depends on symptoms, whether it is

rate or rhythm control

Early treatment and management is key for long term

success

References

• Cox JL. “Cardiac surgery for arrhythmias.” PACE. Vol. 27. (2004):266-282. Print.
• Fuster V, et al. “ACC/AHA/ESC Guidelines for the Management of Patients With Atrial Fibrillation: Executive Summary A Report of the American

College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines and Policy Conferences (Committee to Develop Guidelines for the Management of Patients With Atrial Fibrillation) Developed in Collaboration With the North American Society of Pacing and Electrophysiology.” Circ., Vol. 104, (2001): 2118-2150. Print.

• Issa, Z.F

., Miller, J.M., & Zipes, D.P . (2009). Atrial Fibrillation. In Z.F . Issa, J.M. Miller & D.P . Zipes, Clinical Arrhythmology and Electrophysiology (208-284). Philadelphia: Saunders Elsevier

• Kato et al. “Pulmonary vein anatomy in patients undergoing catheter ablation of atrial fibrillation: lessons learned by use of magnetic

resonance imaging.” Circulation. Vol.107. (2003): 2004-10. Print.

• Konings KT et al. “High-density mapping of electrically induced atrial fibrillation in humans.” Circ. Vol. 89. (1994):1665. Print.
• Medtronic Academy. Pulmonary Vein Isolation Animation.
• Murgatroyd, F

.D., Krahn, A.D., Klein, G.J., Yee, R.K, & Skanes, A..C(2001). Atrial Arrhythmias. In Murgatroyd, F .D., Krahn, A.D., Klein, G.J., Yee, R.K, & Skanes, Handbook of Cardiac Electrophysiology (55-71). London: ReMEDICA Publishing Limited

• Nathan, H., et al. “The Junction Between the Left Atrium and the Pulmonary Veins: An Anatomic Study of Human Hearts.” Circ, Vol. 34,

(1966): 412-422. Print.

• Wijffels et al. “Atrial fibrillation begets atrial fibrillation.” Circ. Vol. 92, (1995):1954.Print.