Abstract
Prior studies on the effects of propranolol on human ventricular refractoriness have yielded occasionally inconsistent results. Most prior studies have examined refractory periods at a single stimulus intensity and without using continuous pacing; thus, the effects of propranolol on repolarization may have not been completely defined. The purpose of the present study was to reevaluate the effects of beta blockade on the human ventricular effective refractory period. Methods: Strength-interval curves were performed in duplicate in a group of 10 patients to demonstrate their reproducibility. Strength-interval curves were performed before and after intravenous propranolol administration in a second group of 10 patients who had no evidence of structural heart disease. Results: Propranolol increased the absolute refractory period from 208 ± 9 milliseconds to 212 ± 10 milliseconds (p= 0.01). However, propranolol decreased the coupling interval at which the strength-interval curve began to show an increase in the stimulus intensity required for capture from 236 ± 8 milliseconds to 232 ± 9 milliseconds. This resulted in a decrease of the width of the strength-interval curve from 28.0 ± 5.1 milliseconds to 20.4 ± 5.5 milliseconds (p < 0.005). Propranolol also significantly increased the slope of a logarithmic fit of the strength-interval curves. Conclusion: Propranolol exerts complex effects on human ventricular refractoriness. Propranolol decreases the width and increases the slope of human strength-interval curve, rather than increasing or decreasing the refractory period. These results have potential implications for antiarrhythmic effects of propranolol.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 210-216 |
| Number of pages | 7 |
| Journal | Journal of Investigative Medicine |
| Volume | 46 |
| Issue number | 5 |
| State | Published - Jan 1 1998 |
| Externally published | Yes |
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Keywords
- Autonomie agents
- Electrophysiology
- Ventricles
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
Cite this
Effects of Intravenous Propranolol on Human Ventricular Strength Interval Curves. / Kadish, Alan H.; Goldberger, Jeffrey; Shah, Amit; Johnson, David.
In: Journal of Investigative Medicine, Vol. 46, No. 5, 01.01.1998, p. 210-216.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Effects of Intravenous Propranolol on Human Ventricular Strength Interval Curves
AU - Kadish, Alan H.
AU - Goldberger, Jeffrey
AU - Shah, Amit
AU - Johnson, David
PY - 1998/1/1
Y1 - 1998/1/1
N2 - Prior studies on the effects of propranolol on human ventricular refractoriness have yielded occasionally inconsistent results. Most prior studies have examined refractory periods at a single stimulus intensity and without using continuous pacing; thus, the effects of propranolol on repolarization may have not been completely defined. The purpose of the present study was to reevaluate the effects of beta blockade on the human ventricular effective refractory period. Methods: Strength-interval curves were performed in duplicate in a group of 10 patients to demonstrate their reproducibility. Strength-interval curves were performed before and after intravenous propranolol administration in a second group of 10 patients who had no evidence of structural heart disease. Results: Propranolol increased the absolute refractory period from 208 ± 9 milliseconds to 212 ± 10 milliseconds (p= 0.01). However, propranolol decreased the coupling interval at which the strength-interval curve began to show an increase in the stimulus intensity required for capture from 236 ± 8 milliseconds to 232 ± 9 milliseconds. This resulted in a decrease of the width of the strength-interval curve from 28.0 ± 5.1 milliseconds to 20.4 ± 5.5 milliseconds (p < 0.005). Propranolol also significantly increased the slope of a logarithmic fit of the strength-interval curves. Conclusion: Propranolol exerts complex effects on human ventricular refractoriness. Propranolol decreases the width and increases the slope of human strength-interval curve, rather than increasing or decreasing the refractory period. These results have potential implications for antiarrhythmic effects of propranolol.
AB - Prior studies on the effects of propranolol on human ventricular refractoriness have yielded occasionally inconsistent results. Most prior studies have examined refractory periods at a single stimulus intensity and without using continuous pacing; thus, the effects of propranolol on repolarization may have not been completely defined. The purpose of the present study was to reevaluate the effects of beta blockade on the human ventricular effective refractory period. Methods: Strength-interval curves were performed in duplicate in a group of 10 patients to demonstrate their reproducibility. Strength-interval curves were performed before and after intravenous propranolol administration in a second group of 10 patients who had no evidence of structural heart disease. Results: Propranolol increased the absolute refractory period from 208 ± 9 milliseconds to 212 ± 10 milliseconds (p= 0.01). However, propranolol decreased the coupling interval at which the strength-interval curve began to show an increase in the stimulus intensity required for capture from 236 ± 8 milliseconds to 232 ± 9 milliseconds. This resulted in a decrease of the width of the strength-interval curve from 28.0 ± 5.1 milliseconds to 20.4 ± 5.5 milliseconds (p < 0.005). Propranolol also significantly increased the slope of a logarithmic fit of the strength-interval curves. Conclusion: Propranolol exerts complex effects on human ventricular refractoriness. Propranolol decreases the width and increases the slope of human strength-interval curve, rather than increasing or decreasing the refractory period. These results have potential implications for antiarrhythmic effects of propranolol.
KW - Autonomie agents
KW - Electrophysiology
KW - Ventricles
UR - http://www.scopus.com/inward/record.url?scp=0032084309&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0032084309&partnerID=8YFLogxK
M3 - Article
C2 - 9676053
AN - SCOPUS:0032084309
VL - 46
SP - 210
EP - 216
JO - Journal of Investigative Medicine
JF - Journal of Investigative Medicine
SN - 1081-5589
IS - 5
ER -