What does this research mean for the field?

Beta-receptor activity is essential for normal hemodynamic adjustments to rapid heart rates, as its blockade leads to decreased aortic flow, increased peripheral resistance, and at very high rates, increased coronary vascular resistance and decreased coronary flow. Novelty: ClaimNovelty.INCREMENTAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

What question did this study set out to answer?

To investigate how beta-receptor blockade influences blood flow and vascular resistance as heart rates increase in unanesthetized dogs.

September 1, 1969Circulation ResearchOpen Access

Effects of Beta-Receptor Blockade on the Systemic and Coronary Hemodynamic Response to an Increasing Ventricular Rate in the Unanesthetized Dog

View Full Paper

Ask AI

Bookmark

Why the study?

Does intravenous propranolol alter the systemic and coronary hemodynamic response to increasing ventricular rates in unanesthetized dogs?

Population

Unanesthetized dogs

Comparison

Intravenous propranolol during ventricular… vs Baseline measurements before beta-receptor…

Design

Preclinical

Authors

FCFred CobbDuke University RBRobert J. BacheAdult Congenital Heart Disease PEPaul A. EbertSan Francisco General Hospital

Discussion

Member takes

Implication

Propranolol may impair coronary flow at high rates in this model; leaves open beta-receptor dependence in human coronary regulation.

Key Points

To investigate how beta-receptor blockade influences blood flow and vascular resistance as heart rates increase in unanesthetized dogs.
Measured coronary and aortic blood flow and arterial pressure during ventricular pacing.
Evaluated changes pre- and post-beta-receptor blockade with propranolol.
Ventricular rates ranged from 120 to 270 beats/min.
Before beta-blockade, coronary flow increased and resistance decreased with heart rate increase; aortic flow remained stable up to 240 beats/min.
After propranolol, coronary flow at rates 120 to 210 beats/min was similar to pre-blockade levels, but aortic flow decreased above 210 beats/min.
Coronary vascular resistance increased and coronary flow decreased at elevated heart rates post-propranolol.

Structured PICO

Does intravenous propranolol alter the systemic and coronary hemodynamic response to increasing ventricular rates in unanesthetized dogs?

Population

Unanesthetized dogs

Intervention

Intravenous propranolol (beta-receptor blockade) during ventricular pacing from 120 to 270 beats/min

Comparator

Baseline measurements before beta-receptor blockade

Outcome

Phasic coronary and aortic blood flow and arterial pressuresurrogate

Beta-receptor activity plays a crucial role in normal hemodynamic adjustments, specifically maintaining coronary flow, during rapid heart rates.

Cite This Study

Cobb et al. (1969) studied this question.

synapsesocial.com/papers/6a1c18124ebd09f3dfa96e66 https://doi.org/10.1161/01.res.25.3.331

View Full Paper

Ask AI

Bookmark

Effects of Beta-Receptor Blockade on the Systemic and Coronary Hemodynamic Response to an Increasing Ventricular Rate in the Unanesthetized Dog

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Effects of Beta-Receptor Blockade on the Systemic and Coronary Hemodynamic Response to an Increasing Ventricular Rate in the Unanesthetized Dog

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Also Consider

Also Consider