Continuous ST segment recording during thrombolysis in acute myocardial infarction: a report on orthogonal ECG monitoring.
BACKGROUND
A noninvasive, real time method is needed to identify failures of thrombolysis and evaluate new treatments in acute myocardial infarction (MI).


OBJECTIVE
To study XYZ monitored ST segment evolution during thrombolysis in acute MI and to examine the correlation of ST parameters to outcome.


METHODS
Thirty-five patients receiving tissue plasminogen activator (tPA) (n = 18) or streptokinase (SK) (n = 17) for acute MI were monitored by vector-cardiography during the first 12 h of thrombolytic therapy. Computer constructed ST vector magnitude (ST-VM) trends were analyzed for 0.5 or greater decline from the initial ST amplitude (IA) lasting for 10 mins or longer (ST response) and for ST re-elevation 0.75 IA or more following ST decline. The degree of ST response, time from treatment onset and ST-VM re-elevation were correlated to peak creatine phosphokinase (CPK), left ventricular ejection fraction (EF) and final ST-VM.


RESULTS
The presence of an ST response correlated with a lower peak CPK (2691 +/- 1625 versus 4057 +/- 1622 U/L, P = 0.043) and tended to higher EF (0.48 +/- 0.11 versus 0.36 +/- 0.09, P = 0.057). The ST responder group had fewer patients with ST re-elevation than the group of nonresponders (13 of 30 versus five of five patients, P = 0.041). Moreover, ST response before 120 mins was associated with lower peak CPK (2089 +/- 1299 versus 3367 +/- 177 U/L, P = 0.02) and better EF (0.54 +/- 0.06 versus 0.41 +/- 0.12, P = 0.02) compared with later or no ST response. The degree of ST response correlated significantly with a lower ST-VM during the last hour (r = -0.744, P = 0.001). ST trends showed no significant differences between treatment groups (tPA versus SK). The tPA group, however, tended to an overall earlier ST response (117 +/- 75 versus 163 +/- 64 mins, P = 0.13).


CONCLUSIONS
Early ST-VM trends are closely associated with electrocardiographic and clinical outcome and may provide a basis for clinical management, therapeutic comparisons and better insight into thrombolysis in MI.
Badir
B F
BF
Research Centre, Hôpital du Sacré-Coeur de Montréal, Québec.
Nasmith
J B
JB
Dutoy
J L
JL
Dubé
B
B
Cardinal
R
R
LeBlanc
A R
AR
Nadeau
R
R
D000368:Aged; D003936:Diagnosis, Computer-Assisted; D004562:Electrocardiography; D005260:Female; D005343:Fibrinolytic Agents / Q000627:therapeutic use*; D006801:Humans; D008875:Middle Aged; D008991:Monitoring, Physiologic; D009203:Myocardial Infarction / Q000503:physiopathology / Q000628:therapy*; D013300:Streptokinase / Q000627:therapeutic use; D015912:Thrombolytic Therapy / Q000379:methods; D010959:Tissue Plasminogen Activator / Q000627:therapeutic use; D014672:Vectorcardiography / Q000379:methods*; D016277:Ventricular Function, Left
D005343:Fibrinolytic Agents; D013300:Streptokinase; D010959:Tissue Plasminogen Activator