Download incidence and course of acute myocardial infarction complicated by

INCIDENCE
AND
COURSE
OF
ACUTE
MYOCARDIAL INFARCTION COMPLICATED BY
SUPRAVENTRICULAR TACHYARRHYTHMIAS
Mykhaylo Sorokivsky MD, Oleg Zharinov MD, PhD, Ulyana Chernyaha-Royko MD,
and Andriy Faynyk MD, PhD
Lviv Regional Cardiology Centre, 35 Kulparkivska Street
Lviv 79015, Ukraine
e-mail: [email protected]
Abstract:
Tachyarrhythmias
are
common
complications
of
acute
myocardial
infarction (AMI) course, often having
influence on patients’ survival prognosis. A
lot of research was dedicated to ventricular
arrhythmias; however supraventricular
tachyarrhythmias (SVT) in AMI patients
still have not been studied enough. In our
study we conducted retrospective analysis
of 2,299 case reports of patients with AMI
to determine the incidence of paroxysmal
supraventricular tachyarrhythmias, their
effect on clinical course and hospital
mortality in patients with acute myocardial
infarction. We also established time of
appearance, duration and number of
recurrent paroxysms of SVT.
INTRODUCTION:
Supraventricular tachyarrhythmias (SVT)
often complicate clinical course of acute
myocardial infarction (AMI), usually
having influence on patients’ clinical
course and survival. They are observed in
7,6-22% of AMI patients.1,2 SVT may
develop acutely following AMI due to
ischemia of the sinus and atrioventricular
nodes or atrial myocardium. In later period
of AMI SVT develop due to early
remodelling of left ventricle, dilatation of
atria, development of congestive heart
failure.1,3 The most common sustained SVT
complicating AMI is atrial fibrillation.
Atrial flutter, atrial and atrioventricular
tachycardias are less prevalent. In some
patients different types of SVT may occur
consequently. Most of data regarding SVT
complicating AMI have been received in
multicenter controlled trials. It has been
reported that SVT developed during AMI
course are associated with increased
number of other AMI complications and
higher
in-hospital
and
long-term
mortality.4-7 However some characteristics
of SVT paroxysms, such as time of onset,
duration, number of paroxysms of recurrent
arrhythmias still need further investigation.
The aim of our study was to determine the
incidence of paroxysmal supraventricular
tachyarrhythmias, their effect on clinical
course and hospital mortality in patients
with acute myocardial infarction. We also
determined time of appearance, duration
and number of recurrent paroxysms of
SVT.
METHODS:
Retrospective study of 2,299 case reports of
patients
with
AMI
consecutively
hospitalized in 2000-2002 years in large
regional cardiology hospital has been
conducted.
Paroxysmal
SVT
were
diagnosed by means of bedside ECG
monitoring within 48 hours after onset of
AMI, ECG registration during arrhythmia
symptoms and in-hospital Holter ECG
monitoring.
RESULTS:
Paroxysmal SVT were registered in 221
(9.61%) patients. Paroxysmal atrial
fibrillation (AF) was found in 158 (6.7%),
atrial flutter – in 24 (1.04%), atrial and
atrioventricular (AV) tachycardias – in 20
(0.87%), combination of various kinds of
paroxysmal SVT – in 19 (0.83%).
Comparative
assessment
has
been
conducted in two groups of patients: group
I (n=221) – AMI complicated by
paroxysmal
SVT,
and
group
II
(representative control group, n=155) –
AMI without paroxysmal SVT. Patients
with
paroxysmal
SVT
appeared
significantly older, with larger number of
346
females, higher incidence of previous AMI
and deeper injury of the myocardium (QAMI)
(p<0.05).
Previous
arterial
hypertension and diabetes mellitus were
registered with similar prevalence in the
compared groups. In the SVT group the
number of smokers was significantly less (p
= 0.02). Higher degrees of chronic heart
failure and left ventricular failure by Killip
were revealed in patients with paroxysmal
SVT. These patients had significantly lower
level of hemoglobin, higher WBC count,
higher levels of AST, ALT and lower
serum potassium in comparison to the
control group (p < 0.05). Diameters of left
atrium
and
right
ventricle
were
significantly larger and the ejection fraction
– significantly lower in patients with SVT
than in the control group.
The course of AMI in patients with SVT
was more often complicated by recurrence
of AMI (p = 0.025), cardiogenic shock (p <
0.01), development of acute left ventricular
failure (p < 0.001) and ventricular
fibrillation (p = 0.03). In-patient prognosis
of patients with SVT was significantly
worse than in the control group (p < 0.001).
Based on multivariate analysis, we
established following independent factors
associated with development of SVT
paroxysms: advanced age, Q-AMI, larger
diameter of left atrium and reduced left
ventricular ejection fraction.
Hospital mortality was 25.95% in patients
with AMI complicated by paroxysmal AF,
37.50% - atrial flutter, 20.0% - atrial and
AV tachycardias, 26.32% - combination of
various SVT, 8.44% - in general group of
patients with AMI and only 6,45% - in
control group.
Due to retrospective character of our study
it was not possible to determine some
characteristics of the paroxysm in all 221
cases. Thus, time of SVT appearance was
determined in 214 cases, number of
paroxysms – in 213, duration of paroxysm
– in 151 cases. Time of appearance,
number of recurrent paroxysms and
duration of the different SVTs are shown in
tables 1-3.
Table 1. Time of the appearance of SVT (n=214)
Day of
Atrial
Atrial Flutter Atrial and
Various SVT All SVT
appearance
fibrillation
AV tachycardias
1 day
77 (50%) 14 (63,64%)
7 (36,84%)
9 (47,36%)
107 (50%)
2 day
13 (8,44%)
0 (0%)
5 (26,32%)
5 (26,32%) 23 (10,75%)
3-5 day
38 (24,68%)
5 (22,72%)
3 (15,79%)
5 (26,32%) 51 (23,83%)
After 5 day
26 (16,88%)
3 (13,64%)
4 (21,05%)
0 (0%)
Table 2. Number of paroxysms of recurrent arrhythmias (n=213)
Number of
Atrial
Atrial Flutter Atrial and
Various
paroxysms
fibrillation
AV tachySVT
cardias
1
106 (70,20%) 21 (87,49%) 13 (68,41%)
33 (15,42%)
All SVT
140 (65,73%)
2
24 (15,89%)
1 (4,17%)
2 (10,53%)
11 (57,89%)
38 (17,84%)
3
7 (4,64%)
1 (4,17%)
2 (10,53%)
2 (10,53%)
12 (5,63%)
>3
14 (9,27%)
1 (4,17%)
2 (10,53%)
6 (31,58%)
23 (10,80%)
347
Table 3. Duration of SVT paroxysms (n=151)
Number of
Atrial
Atrial Flutter Atrial and
Various SVT All SVT
paroxysms
fibrillation
AV tachycardias
< 1 hour
2 (13,33%)
6 (37,50%)
3 (23,08%) 30 (19,87%)
19 (17,76%)
1-3 hours
12 (11,21%)
1 (6,67%)
6 (37,50%)
1 (7,69%) 20 (13,25%)
3-6 hours
22 (20,56%)
3 (20%)
3 (18,75%)
1 (7,69%) 29 (19,20%)
6-12 hours
22 (20,56%)
3 (20%)
1 (6,25%)
4 (30,78%)
30 (19,87%)
12-48 hours
22 (20,56%)
4 (26,67%)
0 (0%)
2 (15,38%)
28 (18,54%)
> 48 hours
10 (9,35%)
2 (13,33%)
0 (0%)
2 (15,38%)
14 (9,27%)
CONCLUSIONS:
Paroxysms of SVT occurred in 9.61%
patients with AMI. Atrial fibrillation was
most common (71.5%) among different
kinds of SVT. SVT prevailed in females
and elderly patients with advanced heart
failure. Development of paroxysmal SVT
in patients with AMI is highly related to
larger myocardial necrosis, left atrium
dilatation and impaired left ventricular
systolic function. Paroxysmal SVT is a
severe complication of AMI. Hospital
mortality of patients with AMI complicated
by paroxysmal SVT is 26.7 %, being much
higher than in AMI patients without this
complication. Short-term prognosis of
patients with AMI complicated by atrial
flutter seems to be worse than in cases of
atrial fibrillation, atrial and atrioventricular
tachycardias. Half of SVT paroxysms
develop on the first day of AMI. Nearly 2/3
of patients developed only one SVT
paroxysm. The majority of atrial fibrillation
and atrial flutter paroxysms lasted more
than 6 hours, paroxysms of atrial and
atrioventricular tachycardias had shorter
duration.
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