CARDIOVASCULAR JOURNAL OF AFRICA • Vol 22, No 4, July/August 2011
AFRICA
217
Letter to the Editor
Use with
β
-blockers
Results from the CARVIVA-HF trial
using carvedilol as the
β
-blocker and
ivabradine have shown that ivabradine
alone or in combination with beta-block-
ers is safe and effective for improving
exercise capacity and quality of life in
patients.
4
The interesting design of CARVIVA-
HF investigated the therapeutic strategy of
up-titrating ACE inhibitors and reducing
heart rate by using three different strate-
gies: carvedilol, ivabradine or a combina-
tion of both drugs. Prior to randomisation
of the 123 patients, beta-blocker therapy
was discontinued for eight weeks to allow
up-titration of ACEI therapy.
Results analysed after 12 weeks
showed improved exercise tolerance,
exercise capacity, quality of life and heart
function with ivabradine alone or when
used in combination with carvedilol, over
baseline and carvedilol-only therapy.
J Aalbers, Special Assignments Editor
1.
Swedberg K, Komajda M, Bohm M,
Borer JS, Ford I, Dubost-Brama A,
et al
.
Ivabradine and outcomes in chronic heart
disease (SHI
f
T): a randomised placebo-
controlled study.
Lancet
2010;
376
: 875–885
2.
ESC heart failure congress, 2011. Oral
presentation: Inger Ekman,
et al
. Ivabradine
is associated with improved health-related
quality of life in patients with heart failure.
3.
ESC heart failure congress, 2011. Poster. J
Camm and associates.
4.
ESC heart failure congress, 2011. Abstract
694. Effect of carvedilol, ivabradine or their
combination on exercise capacity in patients
with heart failure.
Torsades de pointes
Torsades de pointes means twisting of the points. It is a French
term and was first described by Dessertenne in 1966.
1
It refers to
a specific variety of ventricular tachycardia and is characterised
by a twist of the QRS complex around the isoelectric baseline.
The blood pressure drops and ventricular fibrillation can result
in sudden death.
Torsades de pointes is associated with a long QT interval and
it predisposes the patient to an R-on-T phenomenon. Here, the R
wave representing ventricular depolarisation occurs simultane-
ously with the relative refractory period at the end of repolarisa-
tion. An R-on-T phenomenon can initite torsades de pointes.
During torsades de pointes, the heart rotates on its electri-
cal axis at least 180 degrees. There is a long QT syndrome and
prolonged Q-T interval, with long and short R-R intervals and
early premature ventricular contraction.
The causes include diarrhoea, hypomagnesaemia and hypoka-
laemia, anti-arrythmic drugs, hypoxia, acidosis, heart failure, left
ventricular hypertrophy, bradycardia, female gender, hypother-
mia and subarachnoid haemorrhage.
Treatment is to withdraw the offending drug, if any, infuse
magnesium sulphate, and electrical therapy, e.g. an implantable
cardioverter defibrillator.
2,3
HD Solomons
Highlands North, Johannesburg, South Africa
References
1.
Dessertenne F. La tachycardia ventriclaire a deux foyers opposes vari-
ables.
Arch Mal Coeur Vaiss
1966;
59
(2): 263–272. PMID 4956181.
(http;//www.ncbi.nlm.nih.gov/pubmed/4956181.)
2.
Hoshinko K, Ogawa K, Hishitani T, Isobe T, EtoY. Optimal administra-
tion dosage of magnesium sulphate for torsades de pointes in children
with long QT syndrome.
J Am Coll Nutr
2004;
23
(5): 497S–500S.
PMID 15466950.
3.
Hoshiko K, Ogawa K, Hishitani T,Isobe T, Etoh Y. Successful uses
of magnesium sulphate for torsades de pointes in children with
long QT syndrome.
Paediatr Int
2006;
48
(2); 112–117. PMID
16635167. doi; 10.1111/j.1442-200X.2006.02177x(http;//dx.doi.
org/10.1111%2Fj.1442-200X.2006.02177.x).
