| Autor: |
Morady, Fred, DiCarlo, Lorenzo A., Baerman, Jeffrey M., De Buitleir, Michael, Kou, William H. |
| Zdroj: |
Journal of the American College of Cardiology; March 1987, Vol. 9 Issue: 3 p489-499, 11p |
| Abstrakt: |
This study was designed to prospectively determine the Incidence of QRS alternans during various types of narrow QRS tachycardia and to clarify the determinants of QRS alternans. An electrophysiologic study was performed in 28 consecutive patients with a narrow QRS tachycardia. Persistent QRS alternans was observed in 6 (43%) of 14 patients during orthodromic reciprocating tachycarda, 5 (71%) of 7 patients during atrial tachycardia and 3 (43%) of 7 patients during atrioventricular (AV) node reentrant tachycardia. Incremental atrial pacing during sinus rhythm resulted in QRS alternans in patients who had QRS alternans during tachycardia, unless the shortest pacing cycle length associated with 1:1 AV conduction exceeded the tachycardia cycle length. In patients without QRS alternans during narrow QRS tachycardia, incremental atrial pacing during sinus rhythm resulted in persistent QRS alternans in five patients in whom the shortest pacing cycle length associated with 1:1 AV conduction was 60 to 180 ms less than the tachycardia cycle length. In an additional 20 patients without a narrow QRS tachycardia, persistent QRS altertians was observed during incremental atrial pacing in 11 (55%) of the patients. In six of six patients who had QRS alternans during abrupt rapid atrial pacing, QRS alternans was not observed when the same pacing rates were achieved gradually. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
|
