March/April - West Virginia State Medical Association

Scientific Article |
Clinical Cardiac Electrophysiology in West Virginia: 2010
Brett A. Faulknier, DO
Associate Professor of Medicine
WVU Physicians of Charleston
Cardiology and Electrophysiology
Christopher C. Trotter, MD
Internal Medicine Resident
WVU/CAMC Department of
Internal Medicine
Keron B. Navarengom, MD
Internal Medicine Resident
WVU/CAMC Department of
Internal Medicine
Introduction
The last decade has seen an
explosion in the diagnostic and
therapeutic options available to the
clinical cardiac electrophysiologist
(EP) for the treatment of cardiac
arrhythmias. Historically, in West
Virginia, access to an EP physician
has been limited for specialized care
in implantable device and arrhythmia
management. This had led to the
need for devices to be implanted
by other implanters and a backlog
to develop in individuals who may
benefit from potentially curative
catheter based ablation procedures. In
2010 this issue of access is improving
with the recruitment of additional
EPs throughout West Virginia.
Specialized care can be provided in
the areas of atrial fibrillation (AF),
supraventricular and ventricular
arrhythmias (VA), genetic arrhythmia
syndromes and implantable devices.
We review each of these areas and
provide information on up-todate
techniques of diagnosis and
management along with insight
into advances that may open up a
variety of novel clinical strategies.
Atrial Fibrillation
Atrial Fibrillation (AF) is the most
common cardiac arrhythmia affecting
more than 2.3 million people in the
United States. The incidence of AF
is on the rise and the latest United
States census estimates this condition
will affect more than 3 million
people by 2020. The prevalence of AF
increases after age 60: it is now seen
in approximately 10% of individuals
by age 80. 1 Residents of West Virginia
are a prime target for this condition
as diabetes, obesity, heart failure,
coronary and valvular heart disease;
all predisposing conditions for AF,
have a high incidence in our state.
The question of rate control versus
rhythm control has been extensively
studied. Previous evaluations failed
to show benefit from the rhythm
control strategy. 2,3 The question was
recently revisited in AF patients
with heart failure (HF); these
deserve special attention as they
have worse outcomes than those
in sinus rhythm. The multicenter,
randomized un-blinded trial enrolled
1,376 patients with AF and a left
ventricular ejection fraction (EF)
≤ 35% and a history of HF or an
LVEF of ≤ 25%. 4 Rate control was
achieved with beta-blockers with or
without digitalis, and rhythm control
was maintained by cardioversion,
amiodarone, sotalol, or dofetilide.
Patients were followed for 37 ± 19
months for the primary endpoint of
death from cardiovascular causes
(25% in the rate control group vs.
27% in the rhythm control group)
and secondary end points of overall
survival, risk of stroke, or worsening
HF. Secondary end-point outcomes
were also similar between the two
treatment arms. This study once
again failed to confirm benefits of a
rhythm control strategy, and showed
that patients treated with rate
control measures have less need for
hospitalization and for cardioversion.
One important new drug in the
treatment of AF made recently
available in the management of
AF is dronaderone. As its name
suggests, this drug is a class III
multi-channel blocker much like
amiodarone; however, dronaderone
does not contain iodine, and has a
shorter half-life (approximately 24
hours), reducing tissue accumulation.
The efficacy of dronaderone in
preventing recurrent AF has been
well-documented in 2 randomized
placebo controlled trials; however,
these trials excluded patients with
class III and IV HF. 5 The 2008
ANDROMEDA study enrolled 627
patients and tested dronaderone
against placebo in patients with New
York Heart Association (NYHA)
class II-IV HF who were hospitalized
with new or worsening HF (wall
motion index ≤ 1.2, approximating
an EF ≤ 35%). 6 Only 7 months after
its inception this study was ended
because of an increased number of
deaths in the dronaderone treatment
group. A total of 37 patients fulfilled
the primary end point of death, 25
in the dronaderone group, and 12
in the placebo group. The risk of
death associated with dronaderone
was increased among patients with
a lower wall-motion index, and 10
of the 25 dronaderone-associated
deaths had worsening HF when
they died. Also, the number of
patients with a hospitalization for
an acute cardiovascular cause was
higher in the dronaderone group
(71 patients) than in the placebo
group (50 patients) (p=0.02).
The ATHENA trial, published
February 2009, evaluated
dronaderone versus placebo in
patients with AF and additional
risk factors on the primary outcome
of first hospitalization due to
cardiovascular events or death. 7
Additional risk factors included
age ≥ 75, arterial hypertension
(on at least two antihypertensive
drugs of different classes), diabetes
mellitus, prior stroke, transient
ischemic attack, EF≤ 40% and left
atrial diameter ≥50 mm. Patients
with NYHA functional class IV HF
and those with decompensated HF
within the previous 4 weeks were
excluded. After a mean follow-up of
21 ± 5 months, the primary outcome
of first hospitalization or death
occurred in 734 (32%) patients in the
dronaderone group and 917 (39%) in
the placebo group (p