ATRIAL FIBRILLATION IN THE 21 ST CENTURY TIMOTHY DOWLING, D.O. FAMILY PHYSICIAN

Transcription

1 ATRIAL FIBRILLATION IN THE 21 ST CENTURY TIMOTHY DOWLING, D.O. FAMILY PHYSICIAN

2 GOALS AND OBJECTIVES At The end of this talk you should understand: What is Atrial Fibrillation Causes of Atrial Fibrillation The work up for Atrial Fibrillation Treatment of Atrial Fibrillation

3 DISCLOSURES I have no disclosures for this talk today

4 WHAT IS ATRIAL FIBRILLATION? Atrial fibrillation (A fib) is an irregular and often rapid heart rhythm. The irregular rhythm, or arrhythmia, results from abnormal electrical impulses in the upper chambers of the heart that cause the heartbeat to be irregular and usually fast. The irregularity can be continuous, or paroxsymal. Some individuals, especially patients on medications, may have atrial fibrillation constantly but not have a rapid (>100 heartbeats per minute) rate at rest. Variations of A fib may be termed paroxysmal, persistent, or permanent. A fib is the most common heart arrhythmia.

5 ELECTRICAL CONDUCTION OF THE HEART The electrical impulse originates in the SA node of the right atrium. As the impulse travels through the atrium, it produces a wave of muscle contractions. This causes the atria to contract. The impulse reaches the atrioventricular (AV) node in the muscle wall between the two ventricles. There, it pauses, giving blood from the atria time to enter the ventricles. The impulse then continues into the ventricles, causing ventricular contraction that pushes the blood out of the heart, completing a single heartbeat.

6 ATRIAL FIBRILLATION CAN OCCUR IN SEVERAL DIFFERENT PATTERNS Intermittent (paroxysmal): The heart develops atrial fibrillation and typically converts back again spontaneously to normal (sinus) rhythm. The episodes may last anywhere from seconds to days. Persistent: Atrial fibrillation occurs in episodes, but the arrhythmia does not convert back to sinus rhythm spontaneously. Medical treatment or cardioversion (electrical treatment) is required to end the episode. Permanent: The heart is always in atrial fibrillation. Conversion back to sinus rhythm either is not possible or is deemed not appropriate for medical reasons. In most cases, the rate is reduced by medications and the patients are placed on anticlotting medication for their lifetime.

7 ATRIAL FIBRILLATION A COMMON HEART RHYTHM DISORDERS It affects about 4% of the population, mostly people older than 60 years. This amounts to more than 2.6 million people in the U.S. People older than 40 have about a 25% chance of developing A fib in their lifetime. The risk of developing atrial fibrillation increases as we get older. About 10% of people older than 80 years have atrial fibrillation.

8 ATRIAL FIBRILLATION CAUSES Hyperthyroidism Alcohol use Pulmonary embolism Pneumonia

9 ATRIAL FIBRILLATION CAUSES Heart valve disease: This condition results from developmental abnormalities people are born with or can be caused by infection or degeneration/calcification of valves with age. Left ventricular hypertrophy. Coronary heart disease Hypertension Cardiomyopathy

10 ATRIAL FIBRILLATION CAUSES Sick sinus syndrome Pericarditis Myocarditis Advancing age

11 ATRIAL FIBRILLATION DIAGNOSIS The ECG can help distinguish A fib from other arrhythmias that may have similar symptoms (atrial flutter, supraventricular tachycardia, or runs of ventricular tachycardia).

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13 LAB TESTS Complete blood cell count (CBC) Markers for heart injury or stress (enzymes such as troponins and creatine kinase [CK] and BNP) Digoxin drug level (in patients taking this medication) Prothrombin time (PT) and international normalized ratio (INR) Serum electrolytes to evaluate sodium and potassium levels Thyroid function tests for hyperthyroidism

14 CHEST X-RAY This imaging test is used to evaluate for complications such as fluid in the lungs or to estimate heart size.

15 ECHOCARDIOGRAM OR TRANSESOPHAGEAL ECHOCARDIOGRAM This test is done to identify problems in heart valves or ventricular function or to look for blood clots in the atria.

16 ATRIAL FIBRILLATION MEDICAL TREATMENT Treatment for atrial fibrillation traditionally seeks three goals

17 ATRIAL FIBRILLATION MEDICAL TREATMENT Cardiac rate control: The first treatment goal is to slow down the ventricular rate, if it is fast. Beta-blockers: These drugs slow the heart rate by decreasing the rate of the SA node and by slowing conduction through the AV node. Examples include esmolol (Brevibloc), atenolol (Tenormin), propranolol (Inderal), or metoprolol (Lopressor, Toprol XL).

18 CARDIAC RATE CONTROL Cardiac rate control: The first treatment goal is to slow down the ventricular rate, if it is fast. Calcium channel blockers: These drugs also slow heart rate by mechanisms similar to those of beta-blockers.verapamil (Calan, Isoptin) and diltiazem (Cardizem) are examples of calcium channel blockers Digoxin (Lanoxin): This drug decreases the conductivity of electrical impulses through the AV node, but onset of action is slower than beta-blockers and calcium blockers.

19 RESTORE AND MAINTAIN NORMAL CARDIAC RHYTHM About half of the people with newly diagnosed atrial fibrillation will convert to normal rhythm spontaneously in hours. However, atrial fibrillation typically returns in many patients. The frequency with which arrhythmia returns and the symptoms it causes partly determine whether individuals receive rhythm-controlling medication, which is usually termed antiarrhythmia medication. The most commonly used drugs are amiodarone (Cordarone, Pacerone), sotalol (Betapace), propafenone (Rythmol), and flecainide (Tambocor).

20 RESTORE AND MAINTAIN NORMAL CARDIAC RHYTHM Dofetilide (Tikosyn): This is an oral antiarrhythmic drug that must be initiated in the hospital over a three-day period. Hospitalization is needed to closely monitor the heart rhythm during the initial dosing period. If the atrial fibrillation responds favorably during the initial dosing, a maintenance dose is established to be continued at home. Other medications: There are many other drugs in use and they are prescribed to individualize the treatment of A fib. Other drugs can include Ibutilide (Corvert), Dronedarone (Multaq), and Quinidine (Cardioquin, Quinalan, Quinidex, Quinaglute); others may be used rarely. Cardioversion

21 PREVENT CLOT FORMATION (STROKES) Stroke is a devastating complication of atrial fibrillation. Blood clots can form in the atria when their motility is impaired as in A fib. Coexisting medical conditions, such as hypertension, congestive heart failure, heart valve abnormalities, or coronary heart disease, significantly increase the risk of stroke. Age older than 65 years also increases the risk of stroke. The decision to utilize other drugs can be augmented by the CHADS2 score that assigns points to various conditions (congestive heart failure, hypertension, age, diabetes, and previous stroke) in an A fib patient. The higher the points, the more likely the patient is to develop a stroke; some clinicians use this score to help determine what other drugs may help their patients with A fib avoid a stroke.

22 CHADS2 SCORING SCHEME Condition Points C Congestive heart failure 1 H Hypertension 1 A Age > 75 years 1 D Diabetes Mellitus 1 S2 Prior Stroke or TIA 2

23 ANNUAL STROKE RISK WITH RESPECT TO CHADS 2 SCORE CHADS2 Score Stroke Risk % 95% confidence interval

24 ANTICOAGULATION BASED ON THE CHADS2 SCORE Score Risk Anticoagulation Therapy Considerations 0 Low Aspirin Aspirin daily 1 Moderate Aspirin or Warfarin Aspirin daily or raise INR to , depending on factors such as patient risk 2 or greater Moderate or High Warfarin Raise INR to , unless contraindicated

25 ANTICOAGULANTS IN AFIB Warfarin (Coumadin): It reduces the ability of the blood to clot. It lowers the risk of an unwanted blood clot forming in the heart or in a blood vessel. Atrial fibrillation increases the risk of forming such blood clots. It is extremely important to follow the exact dosing prescribed and to have regular blood tests (International Normalized Ratio). Aspirin and clopidogrel (Plavix): These are two commonly prescribed drugs used to reduce the chance of clot development in A fib patients, especially if patients cannot tolerate Coumadin; they also have been used in short-term treatments while a patient is undergoing evaluation for clot formation.

26 ANTICOAGULANTS IN AFIB Heparin and enoxaparin (Lovenox): These similar drugs have been used in short-term treatment of A fib patients; occasionally, Lovenox has been used by some physicians for longer term treatment. Dabigatran (Pradaxa): This thrombin inhibitor is approved for prevention of strokes and thrombus in nonvalvular A fib. There is some controversy about this new drug causing increased heart problems. Rivaroxaban (Xarelto): This factor Xa inhibitor is approved for the prevention of strokes and embolisms associated with nonvalvular A fib; dosing is related to creatinine clearance (CrCl) levels (kidney function).

27 ULIMOEN SR ET AL. COMPARISON OF FOUR SINGLE-DRUG REGIMENS ON VENTRICULAR RATE AND ATRIAL FIBRILLATION. ARRHYTHMIA-RELATED SYMPTOMS IN PATIENTS WITH PERMANENT ATRIAL FIBRILLATION AM J CARDIOL 2013 JAN 15; 111:225.

28 RATE CONTROL FOR ATRIAL FIBRILLATION: WHAT IS THE BEST DRUG TO USE? Ulimoen SR et al. Comparison of four single-drug regimens on ventricular rate and arrhythmia-related symptoms in patients with permanent atrial fibrillation. Am J Cardiol 2013 Jan 15; 111:225. Current guidelines recommend either a beta-blocker or a calcium-channel blocker as first-line rate-control treatment for atrial fibrillation (AF). However, head-tohead trials of the agents in current use are lacking. To compare the effects of four once-daily drug regimens on heart rate and AF-related symptoms in patients with permanent, rapidly conducted AF, investigators in Norway conducted a prospective, randomized, investigator-blind, crossover study.

29 RATE CONTROL FOR ATRIAL FIBRILLATION: WHAT IS THE BEST DRUG TO USE? Sixty adults (mean age, 71; 18 women) with permanent AF and without congestive heart failure or ischemic heart disease received, in randomized order, diltiazem, 360 mg; verapamil, 240 mg; metoprolol, 100 mg; and carvedilol, 25 mg. Each drug was given for 3 weeks to ensure steadystate plasma concentration and adequate washout of the prior treatment. Before the first treatment and on the last day of each treatment protocol, 24-hour Holter recordings were obtained, and patients completed questionnaires on symptom frequency and severity.

30 RATE CONTROL FOR ATRIAL FIBRILLATION: WHAT IS THE BEST DRUG TO USE? The 24-hour mean heart rate was significantly reduced from baseline with all four treatments and was significantly lower with diltiazem than with any other drug: Baseline, 96 beats per minute (bpm) Diltiazem, 75 bpm Verapamil, 81 bpm Metoprolol, 82 bpm Carvedilol, 84 bpm

31 RATE CONTROL FOR ATRIAL FIBRILLATION: WHAT IS THE BEST DRUG TO USE? Deciding which drug to prescribe for heartrate control in patients with atrial fibrillation is a common clinical challenge. In this small, single-center study, diltiazem, at 360 mg per day, appeared to be the best choice. However, these results need confirmation in larger clinical trials and in different populations before any definitive recommendation can be made.

32 INCREASED MORTALITY AMONG PATIENTS TAKING DIGOXIN-ANALYSIS FROM THE AFFIRM STUDY Digoxin was associated with a significant increase in all-cause mortality in patients with AF after correcting for clinical characteristics and comorbidities, regardless of gender or of the presence or absence of HF. These findings call into question the widespread use of digoxin in patients with AF. Eur Heart J (2012) doi: /eurheartj/ehs348 First published online: November 27, 2012

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34 IN CONCLUSION Atrial Fibrillation is a common disease The treatments for Afib continue to evolve What is old may be good or it may be bad When in doubt consult Cardiologist!

35 THANK YOU!