Download The Case of Rate Control:

The Case for Rate
Control:
In the Management of Atrial
Fibrillation
Charles W. Clogston, M.D.
Cardiologist
CHI St. Vincent Heart Clinic Arkansas
April 25, 2015
Atrial Fibrillation
• Atrial Fibrillation is the most common
sustained arrhythmia
• Associated with increased mortality
(1.5-1.9 by Framingham Study)
• Associated with increased morbidity
(both in stroke and limiting symptoms)
Atrial Fibrillation
Consequences
• Deterioration in hemodynamics
(due to increased HR and loss of
AV synchrony)
• Increased risk of stroke secondary
to left atrial thrombi
• Progressive dysfunction of the left
atrium and left ventricle
Goals of Therapy in Atrial
Fibrillation
• Symptom Control
Improved by both rhythm and rate
control
• Prevention of thromboembolism
Achieved with anticoagulation with
warfarin or newer novel anticoagulants
Management Strategies for
Atrial Fibrillation
• Rhythm Control -- uses antiarrhythmic drug
therapy, radiofrequency catheter ablation and/or
surgical (Maze) ablation therapy at time of open
heart surgery. Still requires rate slowing drugs.
• Rate Control – uses drugs that block or slow
conduction thru the AV-node such as beta blockers,
non-dihydropyridine calcium channel blockers or
digoxin. AV-node ablation with ventricular pacing
may be used when drugs are ineffective.
• Both therapies require anticoagulation to prevent
thromboembolism.
Thromboembolic Risk with
Atrial Fibrillation
• Thromboembolism is the most important
adverse outcome.
• Maintaining NSR does not reduce the
frequency despite cardioversion and
antiarrhythmic drugs recurrence rate is 3560% at one year by intermittent monitoring
and as much as 88% by continuous
monitoring for more than 18 months.
Thromboembolic Risk with
Atrial Fibrillation
• Up to 90% of recurrences are asymptomatic
• 17% of asymptomatic events last >48 hours
In a study of pacemakers for arrhythmia
detection in patients with no history of AF, AF
duration of >5 min. increased risk of thromboembolism >6 fold compared with patients
with similar CHADS2 scores and no AF.
Risk factor-based point-based
scoring system - CHA2DS2-VASc
Risk Factor
Score
Congestive Heart Failure/ LV Dysfunction
1
Hypertension
1
Age ≥ 75 years
2
Diabetes Mellitus
1
Stroke/ TIA/ Thrombo-embolism
2
Vascular Disease*
1
Age 65-74
1
Sex Category (i.e. female sex)
1
Maximum Score
9
Adjusted stroke rate according
to CHA2DS2-VASc score
Approach to Anticoagulation in AF
Presumed Benefits of Maintaining NSR
• Fewer symptoms/better exercise
tolerance
• Lower risk of stroke
• Long-term anticoagulation may not
be needed if sinus rhythm is
successfully maintained
• Better quality of life
• Better survival
Trials of Rate vs
Rhythm Control
AFFIRM
Baseline Characteristics
• Age = 69.7 ± 9 years
• 39% female
• >2 days of AF in 69%
• CHF class > II in 9%
• Symptomatic AF in 88%
Studies Comparing Rate and Rhythm
Control
• AFFIRM
• Randomized 4060 patients with recurrent AF
• Goal for rate control of VR<80 bpm at rest and
<110 bpm with 6 minute walk test
• Both received anticoagulation but rhythm
control could remove if patient maintained
NSR. (82 and 63% of patients at 1 and 5
years)
AFFIRM
Cross Over Rates
• Cross over to Rate Control arm occurred in
17 and 38% of patients in Rhythm Control
arm at 1 and 5 years due to inability to
maintain NSR or drug intolerance.
• Cross over to Rhythm Control arm
occurred in 8 and 15% in Rate Control arm
due to failure to control symptoms or CHF.
AFFIRM Findings
• At 3.5 years there was almost a significant decrease
in all cause mortality (primary endpoint) in rate control
arm
• There was no significant difference in the composite
secondary endpoint of death, ischemic stroke, anoxic
encephalopathy, major bleeding or cardiac arrest
• There was no significant difference in global functional
status or quality of life in the initial report
• Number of patients requiring hospitalization was lower
in the Rate Control arm (73 vs 80%)
RACE Trial
Rate Control versus Electrical Cardioversion for Persistent
Atrial Fibrillation Study
• Similar to AFFIRM but
• Enrolled only patients with persistent atrial
fibrillation who had been cardioverted at least
once prior to enrollment and were in recurrent
atrial fibrillation
• Primary end point was a composite of
cardiovascular death, heart failure,
thromboembolism, bleeding, pacemaker insertion,
or severe side effects of antiarrhythmic drugs
Rate Control versus Electrical Cardioversion for
Persistent Atrial Fibrillation (RACE) Trial (n=522)
AF-CHF Results
• No difference in primary endpoint of CV death
between groups (Figure)
• Cardioversion 39% vs 8%
• Also no difference in total mortality (31.8% vs. 32.9%,
p = 0.73), stroke (2.6% vs. 3.6%, p = 0.32), worsening
heart failure (27.6% vs. 30.8%, p = 0.17), or
composite (42.7% vs. 45.8%, p = 0.20)
• Higher hospitalization rates (46% vs 39% p=.006) and
cost with rhythm control
• Bradyarrhythmias ↑ in rhythm control group
Cost Effectiveness of Rate Control over
Rhythm Control
• AFFIRM Trial Cost Effectiveness Analysis
• Patients in the rate-control group used
fewer resources, such as hospital days,
cardioversions, and emergency
department visits
• Estimated cost savings per patient
treated with rate control ranged from
$2189 to $5481 per person
Conclusions
 Ventricular rate control is equally (or more)
effective than rhythm control in terms of survival,
quality of life and other end points
 Current antiarrhythmics have a relatively low
efficacy while having significant cardiac and noncardiac side effects compared with rate control
agents
 There are significant cost savings with rate control
compared with rhythm control