What is the clinical evidence from this study?

Population: Hibernating myocardium (n=8). Intervention: Graded intravenous epinephrine infusion and atrial pacing vs. Resting state. Primary outcome: Myocardial function and metabolism (segment shortening, oxygen consumption, lactate uptake) during stress (p=<0.05).

What question did this study set out to answer?

The aim is to investigate whether hibernating myocardium can adapt to reduced flow and function by retaining metabolic and contractile reserves during stress.

January 10, 2003Circulation Research

Hibernating Myocardium Retains Metabolic and Contractile Reserve Despite Regional Reductions in Flow, Function, and Oxygen Consumption at Rest

Q: What are the key findings of this study?

In a porcine model of hibernating myocardium, epinephrine infusion increased peak segment shortening and oxygen consumption without lactate production, demonstrating retained metabolic reserve.

Q: What question did this study set out to answer?

The aim is to investigate whether hibernating myocardium can adapt to reduced flow and function by retaining metabolic and contractile reserves during stress.

View Full Paper

Ask AI

Bookmark

Key result

In a porcine model of hibernating myocardium, epinephrine infusion increased peak segment shortening and oxygen consumption without lactate production, demonstrating retained metabolic reserve.

Population

Pigs chronically instrumented with a proximal left anterior descending artery stenosis for 3 months to…

Comparison

Graded intravenous epinephrine infusion and… vs Normal controls and remote non-ischemic myocardium

Design

Preclinical

Follow-up

3 months (duration of stenosis before testing)

Authors

JFJames A. FallavollitaCook County Health and Hospitals System BMBrian MalmYale University JCJohn M. CantyCardiac Imaging

Discussion

Member takes

Implication

Retained metabolic reserve in hibernating myocardium supports adaptive downregulation; leaves open translation to human stress testing and management.

Key Points

The aim is to investigate whether hibernating myocardium can adapt to reduced flow and function by retaining metabolic and contractile reserves during stress.
Pigs were chronically instrumented with left anterior descending artery stenosis for 3 months.
Assessment included measurements of perfusion, contractility, and oxygen consumption at rest and during stress tests with epinephrine infusion and atrial pacing.
Oxygen consumption and lactate levels were monitored during various conditions.
Resting myocardial oxygen consumption decreased to 63±3 compared to 77±6 microL x g(-1) x min(-1) in controls (P<0.05).
Contractility increased during stress, with peak segment shortening reaching 17.3±3.1% from depressed levels (P<0.05).
Lactate uptake increased during stress from 0.7±0.1 to 1.2±0.1 micromol x g(-1) x min(-1) (P<0.05) with no evidence of ischemia.

Structured PICO

Population

8 pigs chronically instrumented with a proximal left anterior descending artery stenosis for 3 months to induce hibernating myocardium.

Intervention

Graded intravenous epinephrine infusion and atrial pacing to a rate of 120 bpm

Comparator

Normal controls and remote non-ischemic myocardium

Outcome

Myocardial function (segment shortening), perfusion, oxygen consumption, and lactate metabolism during stresssurrogate

Main Result

p-value: p=<0.05

Hibernating myocardium retains the ability to increase metabolism and function during stress without developing acute ischemia, suggesting that resting downregulation is an adaptive response.

Cite This Study

Fallavollita et al. (2003) studied Hibernating myocardium (n=8). Graded intravenous epinephrine infusion and atrial pacing vs. Resting state was evaluated on Myocardial function and metabolism (segment shortening, oxygen consumption, lactate uptake) during stress (p=<0.05). In a porcine model of hibernating myocardium, epinephrine infusion increased peak segment shortening and oxygen consumption without lactate production, demonstrating retained metabolic reserve.

synapsesocial.com/papers/6a32810281ec1bb6b0ddef05 https://doi.org/10.1161/01.res.0000049104.57549.03

View Full Paper

Ask AI

Bookmark

Implication

Retained metabolic reserve in hibernating myocardium supports adaptive downregulation; leaves open translation to human stress testing and management.

Hibernating Myocardium Retains Metabolic and Contractile Reserve Despite Regional Reductions in Flow, Function, and Oxygen Consumption at Rest

Discussion

Member takes

Implication

Key Points

Structured PICO

Main Result

Cite This Study

Hibernating Myocardium Retains Metabolic and Contractile Reserve Despite Regional Reductions in Flow, Function, and Oxygen Consumption at Rest

Discussion

Member takes

Implication

Key Points

Structured PICO

Main Result

Cite This Study

Also Consider

Also Consider