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530
Letters to the Editor
to that after conventional balloon
angioplasty.
[4] Topol E. Caveats about elective coronary stenting. N Engl J Med 1994;
539^1.
N. M. G. DEBBAS
[5] Sigwart U, Puel J, Mirkowitch V, Joffre
U. SIGWART
F, Kappenberger I. Intravascular stents
to prevent occlusion and restenosis
E. EECKHOUT
after transluminal angioplasty. N Engl
P. VOGT
J Med 1987; 316: 701-6.
J. C. STAUFFER [6] Eeckhout E, Goy JJ, Stauffer JC, Vogt
P, Kappenberger L. Endoluminal stentL. K.APPENBERGER
ing of narrowed saphenous vein grafts:
J. J. GOY
long term clinical and angiographical
Division of Cardiology,
follow-up. Cathet Cardiovasc Diagn
Centre Hospitalier Universitaire Vaudois, 1994; 32: 139-46.
Lausanne, Switzerland
References
The mechanism of catecholaminergic
polymorphic ventricular tachycardia
may be triggered activity due to
delayed afterdepolarization
Bi-directional or polymorphic ventricular tachycardia (VT) is an uncommon disorder whose aetiology and
mechanism is unknown. There are a
few reports on patients with bidirectional or polymorphic VT in the
absence of structural heart disease.
Among them, Leenhardt et al. have
reported cases of catecholaminergic
polymorphic VT[1).
Figure 1 (a) Twelve-lead electrocardiogram during bidirectional VT. There is an
alternating pattern of right and left bundle branch block (R/LBBB), or an
alternating left and right axis deviation with an RBBB or LBBB pattern. Thus,
QRS pattern varied, (b) Recordings of MAP at right ventricular inflow. After
bidirectional VT induced spontaneously by emotion disappeared, humps are
observed during phase 4 (arrows) (c) During the infusion of isoproterenol, the
humps gradually increased (arrows), (d) After the injection of propranolol, the
humps gradually reduced and finally disappeared.
Eur Heart J, Vol. 18, March 1997
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[1] Serruys PW, de Jaegere P, Kiemeneij F
et al. A comparison of balloon expandable stent implantation with balloon
angioplasty in patients with coronary
artery disease. N Engl J Med 1994; 331:
489-95.
[2] Fischman DL, Leon MB, Bairn DS
et al. A randomized comparison of
coronary stent placement and balloon
angioplasty in the treatment of coronary artery disease. N Engl J Med
1994; 331: 496-501.
[3] Kimura T, Nosaka H, Yokoi H,
Iwabuchi M, Nobuyoshi M. Serial
angiographic follow-up after PalmazSchatz stent implantation: comparison
with conventional angioplasty. J Am
Coll Cardiol 1993; 21: 1557-63.
We also had a case of catecholaminergic polymorphic VT. A
14-year-old Japanese male was
referred to us for the evaluation of
ventricular tachyarrhythmias. Since
the age of 5 years, he had experienced
several episodes of syncope due to
ventricular tachyarrhythmia associated with exercise or an increase in
physical activity. His family history
revealed no evidence of syncope or of
sudden death. Physical examination
revealed a slow pulse rate, and a cardiac pansystolic murmur (Levein 2/6)
was audible at the apex of the heart.
Results of biochemical tests were normal. The resting 12-lead ECG showed
sinus bradycardia with a rate of 42
beats, min" 1 , a normal QT interval
with QTc 0-41 s. Chest X-rays showed
a cardiothoracic index of 0-48.
Echocardiography
revealed mild
mitral valve regurgitation, but good
ventricular function. Cardiac catheterization revealed normal coronary
arteries. Despite the presence of mild
mitral valve regurgitation, we were
convinced that structural heart disease
was absent. In this case, bidirectional
or polymorphic VT was reproducibly
induced by humoral (exercise, isoproterenol injection) or neurogenic
(stress, emotion) sympathetic stimu-
Letters to the Editor
T. NAKAJIMA
Y. KANEKO
Y. TANIGUCHI
K. HAYASHI*
T. TAKIZAWA
T. SUZUKIt
R. NAGAI
The Second Department of
Internal Medicine, and
*The Third Department of
Internal Medicine,
Cunma University School of Medicine,
^College of Medical Care and Technology,
Gunma University,
Maebashi 371, Japan
and an end-systolic volume (ESV) of
[1] Leenhardt A, Lucet V, Denjoy I et al. 160 ml at rest (heart rate (HR) 76/min,
Catecholaminergic polymorphic ven- ejection fraction (EF) 45%). After extricular tachycardia in children; a ercise the EDV was 283 ml and the
7-year follow-up of 21 patients. Circu- ESV was 201ml (HR112/min, EF
29%). HELP LDL apheresis (B.
lation 1995; 91: 1512-9.
[2] Franz MR. Method and theory of Braun, Melsungen, Germany) was
monophasic action potential recording performed every 2 weeks over a period
(review). Prog Cardiovasc Disease of 6 months for a total of 12 treat1991; 33: 347-68.
ments. The average cholesterol reduc[3] Bonatti V, Rolli A, Botti G. Recording tion after apheresis was 54%, LDLof monophasic action potentials of the cholesterol reduction was 61% and
right ventricle in long QT syndromes
complicated by severe ventricular fibrinogen reduction was 55%. After 6
arrhythmia. Eur Heart J 1983; 4: months, another exercise thallium-201
SPECT was performed. The images
168-79.
[4] Shimizu W, Ohe T, Kurita T et al. Early acquired revealed the persistence of
afterdepolarizations induced by iso- the area of necrosis but no marginal
proterenol in patients with congenital ischaemia (Fig. 1 (B)). Radionuclide
long QT syndrome. Circulation 1991; ventriculography showed a left ven84: 1915-23.
tricular EDV of 264 ml and an ESV of
129 ml at rest (HR 80/min, EF51%).
During exercise the EDV was 239 ml
Improvement of myocardial perfusion
and the ESV was 170 ml (HR 115/min,
after low-density lipoprotein apheresis
EF 29%).
treatment
We found an improvement
Low-density lipoprotein (LDL) apher- in myocardial perfusion, as assessed
esis (the selective extracorporeal re- by exercise thallium-201 SPECT,
moval of LDL cholesterol from accompanied by an improvement
plasma) is used to treat patients with in radionuclide ventriculography pardrug-refractory hypercholesterolaemia ameters after 6 months treatment with
and coronary heart disease. There HELP LDL apheresis. Long-term
are currently three LDL apheresis HELP LDL apheresis can induce remethods in clinical use'11: immuno- gression of coronary artery stenoses'21.
adsorbtion with anti-apolipoprotein B However, numerous atherosclerosis
antibodies, dextransulfate adsorption regression trials have revealed that the
and heparin-induced extracorporeal clinical benefit derived from cholesLDL precipitation (HELP). We report terol lowering is greater than one
the case of a patient who showed a would expect from the minimal
notable improvement of myocardial changes observed by coronary angiogperfusion after 6 months of HELP raphy. This has prompted investigators to use other methods to evaluate
LDL apheresis.
31
The patient, a 69-year-old the effects of cholesterol lowering' .
Its
influence
on
endothelial
function
woman, had suffered a postero-basal
myocardial infarction at the age of 57. and myocardial perfusion needs to be
Eight years later she underwent cor- studied. In two recently published
onary bypass surgery in our hospital. studies, improvements in myocardial
detected by thalliumAt that time we diagnosed familial perfusion were
41
hypercholesterolaemia and initiated 201 SPECT' and51 by positron emistreatment. Because her response to sion tomography' 3 and 6 months,
diet and drug therapy was insufficient, respectively, after the cholesterolLDL apheresis was begun one year lowering intervention was started. The
later. She was treated for 20 improvement observed in this patient
months with immunoadsorbtion LDL is probably due to a reversal of
apheresis (Baxter, Unterschleissheim, endothelial dysfunction, although,
Germany) once every 2 weeks. There- because of the previous treatment with
after the treatment method was immunoadsorbtion LDL apheresis,
plaque regression also remains a
switched to HELP LDL apheresis.
possibility. The reduction of plasma
Before the switch, exercise fibrinogen may also contribute to
thallium-201 single-photon emission better perfusion of the myocardium
computed tomography (SPECT) was by favourably influencing blood
performed. The images obtained were rheology.
consistent with an area of necrosis
with marginal ischaemia. (Fig. 1(A)).
This is, to our knowledge, the
A technetium-99m radionuclide ven- first case of myocardial perfusion
triculogram revealed a left ventricular improvement under LDL apheresis
end-diastolic volume (EDV) of 290 ml documented by thallium-201 SPECT.
References
Eur Heart J, Vol. 18, March 1997
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lation. Twelve-lead ECG during bidirectional VT show various QRS
complexes (Fig. 1 panel (a)). These
ventricular tachyarrhythmias were
halted by an injection of verapamil,
12 mg, or of propranolol, 2 mg, and
were prevented by the administration
of oral propranolol, 110 mg daily.
Programmed electrical stimulation including triple extrastimuli of
the right ventricle did not induce
ventricular tachyarrhythmias. Monophasic action potential (MAP)'21 recording at the inflow of the right
ventricle exhibited humps during
phase 4 of the MAP (panel (b)). Similar humps were not recorded in other
parts of the right ventricle. The humps
gradually increased during the infusion of isoproterenol, 002mg. h ~ ' ,
and were followed by the occurrence
of ventricular premature beats (panel
(c)), then by the appearance of bidirectional VT. An injection of
propranolol, 2 mg, led to a gradual reduction, and finally, a disappearance of the humps (panel (d)),
accompanied by a disappearance of
the bidirectional VT.
From the MAP recordings and
the effects of the drugs administered to
this patient, it is conceivable that the
humps observed during phase 4 of the
MAP recordings may reflect delayed
after depolarization (DAD) and bidirectional VT may be triggered
by DAD-induced triggered activity.
While DAD could be recorded only at
the right ventricular inflow in this case,
multiple separate foci may induce
DAD. This fact is of interest, considering the difference between the
idiopathic long QT syndrome and catecholaminergic polymorphic VT[I'3'41.
This is the first case of
catecholaminergic polymorphic VT
where DAD could be recorded on
MAP recordings.
531