The AHA Guidelines and Scientific Statements Handbook

Chapter 17 Ventricular Arrhythmias and Sudden Cardiac Death

chaired by A. John Camm, MD, and Douglas P.
Zipes, MD. It was reviewed by offi cial reviewers, two
nominated by the ACC, two by the AHA, two by the
ESC, one from the ACC/AHA Task Force on Prac-
tice Guidelines, reviewers from the EHRA and HRS,
and 18 content reviewers, including members from
ACCF Clinical Electrophysiology Committee, AHA
Council on Clinical Cardiology, Electrocardiogra-
phy, and Arrhythmias, and AHA Advanced Cardiac
Life Support Subcommittee.
The guideline process included a comprehensive
search of the scientifi c and medical literature on
ventricular arrhythmias and sudden cardiac death
(SCD) (limited to publications on humans and
in English from 1990 to 2006). Specifi c targeted
searches were performed on ventricular arrhythmias
and SCD and a variety of subtopics (Table 17.1).
The fi nal recommendations for each indication
were derived from both clinical evidence and expert
opinion and were classifi ed in the agreed ACC/
AHA/ESC format.

Recommendations by various
organizations for the management of
patients with ventricular arrhythmias and
the prevention of sudden cardiac death

There have been several guidelines dealing with
the management of sudden death and ventricular
arrhythmias, particularly using implantable devices
[1–7]. Others have followed the publication of these
guidelines [8].
The guideline writers faced a particular problem;
European Heart Failure Guidelines had made man-
agement recommendations based on measurements
below a range of ejection fractions (EFs). Others had
used specifi c single EF cut-points. Thus recommen-
dations for prophylactic ICD implantation based on

EFs had been inconsistent (Table 17.2) because clini-

cal investigators had chosen different EFs for enroll-

ment in trials of therapy, average values of the EF in

such trials have been substantially lower than the cut-

off value for enrollment, and subgroup analyses of

clinical trial populations based on EF have not been

consistent in their implications. Substantial differ-

ences between guidelines have resulted. However, no

trial has randomized patients with an intermediate

range of EFs. For instance, there is no trial that has

specifi cally studied patients with an LVEF between

31% and 35% and hardly any trial has specifi cally

reported data relating to patients with EFs in this

range, yet recommendations have been set for such

patients on the basis of data derived from trials that

studied groups with EFs less than or equal to 30%,

others that enrolled patients with an EF less than or

equal to 35%, and one trial that enrolled patients with

an EF less than or equal to 40%. Recognizing these

inconsistencies, this Guideline Writing Committee

decided to construct recommendations to apply to

patients with an EF less than or equal to a range of

values. The highest appropriate class of recommenda-

tion was then based on all trials that recruited patients

with EFs within this range. In this way, potential con-

fl icts between guidelines were reduced and errors due

to drawing false conclusions relating to unstudied

patient groups were minimized.

Although this led to consistent recommendations,

data relating to that range of 35–40% in post-

infarction patients is very sparse and relates only to

those also with nonsustained ventricular tachycar-

dia. Since these guidelines were published the rec-

ommendation of ICD implantation in post-MI

patients with an EF <30–40% have generally been

translated into ICD implantation in patients post

MI patients with EF <30–35% [Level of Evidence

Table 17.1 Pathologies, arrhythmias, investigations, therapies and specifi c groups considered in these guidelines

Pathologies Clinical presentations Investigations Therapies Specifi c Groups

Acute coronary syndrome Acute specifi c arrhythmias ECG Drug therapy Gender
Heart failure Ventricular tachycardia Exercise testing ICD and AED Pediatric
Congenital heart disease Ventricular fi brillation Echocardiography Ablation Elderly
Cardiomyopathy Torsades de pointes Imaging Surgery Athletes
Endocrine disorders Drug-induced arrhythmias Electrophysiological testing Resuscit-ation Genetic arrhythmias
Myocarditis Structurally normal hearts Renal failure