CCMS Medicine Summer 2017 - 8

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BY MIAN A. JAN, MD, FACC, FSCAI
PRESIDENT OF CHESTER COUNTY MEDICAL SOCIETY

Mother of all Arrhythmias Part 2
BY MIAN AND ZARSHAWN JAN

Prevalence
Atrial
fibrillation (AF) is the most common arrhythmia in the US.
Management

Four percent of patients over the age of sixty will have AF, similarly
mainofgoal
is to prevent
of AFhave
on the
eightThe
percent
patients
over thethe
ageeffect
of eighty
AF, and
cardiovascular
system
and
prevent
stroke.
The
effect
onfirst
thetime
fourteen percent will develop AF in their lifetime. The
cardiovascular
system
is
blunted
by
rhythm
or
rate
control
this irregularity was described by Jean Baptiste Senac was inand
1749
stroke
prevented
by anticoagulation.
and
wasisfirst
documented
by ECG by Thomas Lewis in 1909.
* Rate vs Rhythm control
Although rhythm control is preferred because it is closer to
natural homeostasis, it may not be achievable and a significant
body of data has shown similar outcomes in rate vs rhythm
control.
Rate control is the method we usually adopt if we cannot
keep patients in Sinus Rhythm because of large atrial size or other
factors.
* Rate control
keep
a rate
between
andto
100
beats per
MenWe
aretry
onetoand
a half
times
more60
likely
develop
AF minute.
than
women
andused
Caucasians
develop
more
than
Americans.
Drugs
usually affect
theitAV
node
andAfrican
decrease
conduction
across the node, slowing the rate. These are the major ones:

Classification
* Beta Blockers; try to use cardioselective rather than non-

There
is certain and
terminology
that we needatenolol,
to remember
and and
cardioselective
include metoprolol,
bisoprolol
understand:
nebivolol.
* Calcium Blockers; use non-dihydropyridine calcium channel
blockers, such as diltiazem and verapamil.
* Glycoside Digoxin; recently the use has diminished
significantly since they are not as effective as newer drugs.
* Amiodarone; has AV nodal blocking ability but should only
be used as last resort for rate control because of potential side
effects.
* Rhythm control
First detected:
less than
hours
during
diagnosis
There areusually
two methods
to forty-eight
keep patients
in sinus
rhythm.
Paroxysmal: less than seven days and self-terminating
* Electrical
rhythm
using
DC or
Persistent:
existscardioversion:
for more thanrestoration
seven daysof
and
requires
electrical
cardioversion;
usually
the
patient
needs
to
be
on
anticoagulants
or
pharmacological cardioversion
accompanying
transesophageal
echo
excludes
atrial
thrombus.
Permanent: sustained with failed cardioversion and everyone is in
agreement that rate control is the best option

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Lone AF: usually benign occurring in younger patients, no
underlying cause, few symptoms and no structural heart disease.
* Chemical cardioversion is performed with drugs such as
amiodarone, dronedarone, procainamide, dofetilide, ibutilide,
propafenone, or flecainide, all with varying success and side
effects. Even with chemical conversion the patient should be
anticoagulated.
* Ablation in younger patients where rhythm control is
desired and cannot be maintained by medication or cardioversion,
radiofrequency or cryoablation may be attempted. More recently
ablation for AF has become a more accepted intervention but
definite evidence that ablation reduces all cause mortality, stroke,
or heart failure is still being gathered. Two ongoing clinical trials
(CABANA [Catheter Ablation vs. Antiarrhythmic drug therapy for
atrial fibrillation]
and EAST [early therapy for stroke prevention
Signs
and Symptoms
trial]) should
new information
forcan
assessing
whether AF
Usually
relatedprovide
to the rapid
heartbeat and
vary from
ablation is superior
to more
therapy.
palpitations
to syncope.
The standard
symptoms
can be vague like exercise
intolerance
and fatigue
to devastating
like surgical
CVA, CHF,
and angina
* The MAZE
procedure
is an invasive
treatment
of AF
pectoris.
Sometimes
the
symptoms
are
so
minimal
diagnosis
is
often performed during coronary artery bypass surgery.
made by routine ECG.
Often symptoms depend on the primary cause of AF and mimic
Anticoagulation
their
presentation.
Anticoagulants are our major armamentarium against stroke

Pathophysiology
in rate control patients and we are going to explain the types,

Normally
node
functions,the
andsinoatrial
indications
of (SA
theirnode)
use. in the right atrium
generates regular electrical impulses which results in mechanical
* Types In AF this impulse is overwhelmed by disorganised
contraction.
electrical activity located in the root of pulmonary veins. This
leads to irregular conduction of electrical impulse down the
atrioventricular node (AV node) and thus a faster irregular
heartbeat. Fortunately 300 to 500 impulses generated in the atria
are hampered by
their route down
the AV node and
only 100 to 150
reach the ventricle
or AF would be
immediately life
threatening. One
such scenario
is the accessory
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Table of Contents for the Digital Edition of CCMS Medicine Summer 2017
