Vol 9, No 1
- Neuropsychiatry and Cardiovascular Disease
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Poster
Cardiac adverse reactions associated
with psychotropic drugs
Sudden death
A 10-year cohort study found a 1.33-fold relative risk of
death in a schizophrenic population compared with a
control population;the leading cause of death was car-
diovascular disease.
6
In patients with myocardial infarc-
tion and cardiac failure,reduced heart rate variability is
one of the predictive factors of increased risk of cardiac
death
7
;this reduced heart rate variability might be due
to the anticholinergic effects of psychotropic drugs.
8
Polymedication was also identified as an independent
risk factor for death.
6
Thioridazine,an old and widely prescribed neuroleptic
drug which was recently withdrawn,was associated with
75% of 49 deaths in a patient group taking a single
antipsychotic drug regimen;its potential for QT prolon-
gation had already been reported in 1963.
9,10
Unexplained
sudden death in young adults has been linked to the pre-
scription of antipsychotics other than thioridazine.
11
QT interval
Electrocardiographic modifications due to psychotropic
drugs include prolongation of the PQ interval (atrioven-
tricular blocks of different degrees of severity),widening
of the QRS interval (bundle branch block),ST-segment
changes (repolarization disturbances),and prolongation
of the QT interval.
Drug-induced long QT syndrome is an underestimated
adverse drug effect:morbidity and mortality associated
with a prolongation of the QT interval currently consti-
tute the most frequent cause of drug withdrawal from the
market or “black-box”warning after marketing.
12
In
1920,Bazett found that the repolarization phase was
related to ventricular systole,and that its duration was
mainly influenced by the heart rate.
13
Bazett's formula
corrects the QT interval with an approximation for a rate
of 60/min as follows:QT
c
=QT/
RR
,expressed in sec-
onds
(Figure 1)
.
Copyright © 2007 LLS SAS. All rights reserved
Rates of cardiovascular morbidity and mortality in psychiatric patients are higher than in the
general population:it is estimated that those who suffer from schizophrenia have a life expectan-
cy approximately 20% shorter than those who do not,and this difference is not fully accounted
for by suicide or accidental death.
1
Cardiovascular adverse effects of psychotropic drugs are
common,and potentially harmful.
2
The most serious cardiovascular consequences of psy-
chotropic drugs are arrhythmias and sudden death,which principally result from torsades de
pointes following progressive QT interval prolongation.Less severe cardiac adverse drug reac-
tions are extremely common.Orthostatic hypotension,vasodilatation with transient collapse,and
reflex sinus tachycardia due to
a
1
-adrenoceptor blockade and to anticholinergic effects occur at
therapeutic dosages of several psychotropic drugs.Postural hypotension was found in 77% of
patients receiving antipsychotic medication versus 15% receiving placebo,and a correlation was
found with drug dosage.
3
Furthermore,antipsychotic drug use is associated with an increased
risk of hip fracture with a relative risk of 2 (confidence interval [CI],1.6 to 2.6) and accounts for
a third of all falls in nursing homes.
4,5
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