International Journal of Interventional Cardioangiology

INTERVENTIONAL CARDIOLOGY
tion of thrombolytic therapy –ST elevation rises up
to 160% from baseline within 9 minutes. Further
ST-segment starts to decrease reaching the prepeak
values within 9 minutes, and in 95 minutes ST
segment decreased staying at the same level within
the next day. Development of the sharp peak of
increase in ST-segment elevation in 15 minutes after
thrombolytic administration was accompanied by the
episodes of idioventricular rhythm with heart rate 58
to 78 beats per minute lasting up to 1 minute, which
were considered to be the reperfusion arrhythmias.
The example of similar changes in ST-segment in
inferior AMI is shown on figures 2, 3. A 59 years old
patient diagnosed with the peracute phase of inferior
AMI was hospitalized within 5 hours 20 minutes from
the onset of first in life angina attack. Maximal degree
of ST elevation was 180 uV and was observed in lead
III. Thrombolytic therapy was started. In 20 minutes
dramatic peak of increase in ST elevation to 280 uV was
recorded, which corresponds to 155% of the baseline
value. ST elevation raised to maximal values within 3
minutes, and then ST-segment decreased rapidly to
baseline level within 7 minutes; and within 36 minutes
ST was stabilized at 50 uV level remaining the same
within the next day. STIII level was 50 uV on the control
ECG recorded in 90 minutes after the drug administration,
ST-segment decreased by 72% from baseline suggesting
the effective thrombolytic therapy. Reperfusion
arrhythmias were recorded in time period near the ST
peak, in this patient the arrhythmias were manifested
as episodes of severe sinus bradycardia up to 41 beats
per minutes, frequent ventricular extrasystoles, and
episodes of unstable ventricular tachycardia.
It is worth noting that there were no recurrent
angina attacks at the moment of sharp-pointed ST
peak recording in any patient.
Dramatic intermittent character of increase in
ST elevation suggested an immediate relationship
between the peak and reperfusion moment. The
data from the experimental studies provided basis
of this hypothesis. Thus, studies using intramyocardial
electrodes described rapid hyperpolarization of
cells during reperfusion, greater decrease in action
potential duration compared to ischemia period
that was accompanied by superficial ECG changes
expressed as a positive shift of TQ, ST and T-wave
peak (9).
If the observed sharp-pointed peak is caused by
blood flow restoration in the infarct-related artery,
then rapid decrease in ST level was to be expected.
Indeed, when sharp reperfusion ST peak was recorded
during thrombolytic therapy, ST level was normalized
more rapidly in 79% of patients as compared to
the group without specific peak (table 1).
In the group with peak, the ST-segment decreased
fully and stabilized at the level close to the isoelectric
line – within 100±51 minutes from the initiation of
thrombolysis. On the contrary, in the group without
“reperfusion” peak, the time of the ST-segment
decrease was 220±149 minutes, but in 5 patients ST
decrease was not revealed during 36 hours. In the
group without typical sharp pointed peak, the time
of ST decrease to isoelectric line was more than 140
minutes in 76% of patients, whereas in the group
with peak – in 26% only (differences between groups
p=0.00095 by Fisher method).
Figure 1. Typical character of ST changes over time with peak of
increase in ST elevation during thrombolytic therapy. The
arrow indicates the moment of prourokinasa administration.
Typical ST pattern characteristics are shown on the magnified
fragment of the diagram.
Figure 2. Example of ST changes over time with specific peak of
increase in ST elevation in inferior AMI. The arrow indicates
the moment of prourokinaza administration. See explanations
in the text.
Types of ST Segment Resolution during Thrombolytic Therapy
in Patients with Acute Coronary Syndrome
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