[Early invasive strategy in patients with myocardial infarction and intraventricular conduction disturbances and plasma B-type natriuretic peptide levels assessed 6 months after myocardial infarction].
The aim of the study was to assess plasma B-type natriuretic peptide (BNP) levels in patients after myocardial infarction (MI) with intraventricular conduction defects (IVCD) and to define relationship between BNP level, treatment strategy and left ventricular performance.


METHODS
Four types of IVCD were noted: left bundle branch block (LBBB), right bundle branch block (RBBB), left anterior hemiblock (LAH) and left posterior hemiblock (LPH). A total of 158 patients six months after MI treated either invasively or conservatively were included. Of them 126 had IVCD (group A): LBBB-31, RBBB-36, LAH-130, LPH-29, whereas 32 patients without IVCD served as controls (group B). Plasma BNP levels were measured using an immunoenzymatic method. All subjects underwent echocardiography to evaluate left ventricular function.


RESULTS
In group A significantly lower plasma BNP levels (186.3 vs 355.3 pg/mL; p < 0.01) and significantly higher left ventricular ejection fraction (EF) (48.4 vs 42.4%; p < 0.05) were noted in favour of invasive treatment. In group B differences between plasma BNP level and echocardiographic parameters of left ventricle function were insignificant. In patients with LBBB plasma BNP levels were significantly lower in those treated invasively (163.9 vs 528.9; p < 0.01). Also, left ventricular EF and myocardial performance index (MPI) were comparable, whereas E/A value was lower as compared with patients treated conservatively (p < 0.05). There were no significant differences in BNP levels in groups with RBBB, LAH and LPH. Multifactorial regression analysis showed that BNP levels were most strongly correlated with magnitude of the ejection fraction EF (p < 0.001). Other parameters which affect significantly BNP level were MPI: OR 9.07 (95% CI 1.03-79.58; p < 0.05) and E/A: OR 6.58 (95% CI 1.01-42.76; p < 0.05).


CONCLUSIONS
Invasive strategy in MI with IVCD, especially with LBBB, correlates with lower plasma BNP levels six months after index procedure. In patients with IVCD post MI plasma BNP level is better marker of dysfunction of the left ventricle than its ejection fraction.
Oddzial Kardiologii Swietokrzyskie Centrum Kardiologii w Kielcach.
Katarzyna
K
Ciuraszkiewicz
Janusz
J
Sielski
Agnieszka
A
Janion-Sadowska
Marcin
M
Sadowski
Marianna
M
Janion
D000368:Aged; D015415:Biomarkers / Q000097:blood; D002037:Bundle-Branch Block / Q000097:blood*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood* / Q000000981:diagnostic imaging* / Q000628:therapy; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D013318:Stroke Volume; D016896:Treatment Outcome; D014463:Ultrasonography; D018487:Ventricular Dysfunction, Left / Q000097:blood / Q000000981:diagnostic imaging
D015415:Biomarkers; D020097:Natriuretic Peptide, Brain