What is the clinical evidence from this study?

Study design: Other. Population: Cardiac tamponade (n=8). Intervention: Cardiac tamponade vs. Control. Primary outcome: Fall in peak LV pressure with normal inspiration (p=<0.001).

What question did this study set out to answer?

Determine the physiological mechanisms responsible for paradoxical pulse and biventricular mechanical interactions during cardiac tamponade.

December 1, 1993AJP Heart and Circulatory Physiology

Physiology of cardiac tamponade and paradoxical pulse in conscious dogs

Q: What are the key findings of this study?

Experimental cardiac tamponade in conscious dogs caused peak LV pressure to fall by 20.3 +/- 3.7 mmHg during inspiration compared to 7.7 +/- 1.3 mmHg at control (P<0.001).

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

Determine the physiological mechanisms responsible for paradoxical pulse and biventricular mechanical interactions during cardiac tamponade.

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Key result

Experimental cardiac tamponade in conscious dogs caused peak LV pressure to fall by 20.3 +/- 3.7 mmHg during inspiration compared to 7.7 +/- 1.3 mmHg at control (P<0.001).

Population

8 conscious dogs with intact pericardia

Comparison

Cardiac tamponade vs Control state (baseline without tamponade)

Design

Preclinical

Authors

MSMichael A. SavittRush University Medical Center GTGeorge S. TysonUnited States Department of Veterans Affairs JEJoseph R. ElbeeryEast Carolina University

Discussion

Member takes

Implication

Informs pulsus paradoxus mechanisms in tamponade; leaves open translation to human pathophysiology and care.

Key Points

Determine the physiological mechanisms responsible for paradoxical pulse and biventricular mechanical interactions during cardiac tamponade.
Assessed biventricular geometry and chamber volumes in eight conscious dogs (N=8) with intact pericardia using implanted ultrasonic dimension transducers.
Measured right ventricular, left ventricular, pleural, and pericardial pressures simultaneously using high-fidelity micromanometers during baseline and tamponade conditions.
Inspiratory reduction in peak left ventricular pressure increased from 7.7 +/- 1.3 mmHg during control to 20.3 +/- 3.7 mmHg during cardiac tamponade (P < 0.001).
During peak inspiration in tamponade, end-systolic pressure was 19.1 +/- 10.2 mmHg below the baseline curve (P < 0.01), and stroke work was 24.2 +/- 8.8% below the baseline end-diastolic volume curve (P < 0.01).
Tamponade induced an inspiratory leftward shift of the interventricular septum, negative transeptal pressure, and septal arc shortening below its unpreloaded length.

Structured PICO

Population

8 conscious dogs with intact pericardia undergoing experimental cardiac tamponade.

Intervention

Cardiac tamponade

Comparator

Control state (baseline without tamponade)

Outcome

Changes in peak left ventricular pressure, biventricular geometry, and volumes during inspirationsurrogate

Main Result

Absolute Event Rate: 20.3% vs 7.7%

p-value: p=<0.001

In a conscious dog model, paradoxical pulse during cardiac tamponade is driven by inspiratory leftward interventricular septal shifting that unloads the septum and causes transient inspiratory LV dysfunction.

Cite This Study

Savitt et al. (1993) studied Cardiac tamponade (n=8). Cardiac tamponade vs. Control was evaluated on Fall in peak LV pressure with normal inspiration (p=<0.001). Experimental cardiac tamponade in conscious dogs caused peak LV pressure to fall by 20.3 +/- 3.7 mmHg during inspiration compared to 7.7 +/- 1.3 mmHg at control (P<0.001).

synapsesocial.com/papers/6a9ecbcaba37a6179111f53a https://doi.org/10.1152/ajpheart.1993.265.6.h1996

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Physiology of cardiac tamponade and paradoxical pulse in conscious dogs

Discussion

Member takes

Implication

Key Points

Structured PICO

Main Result

Cite This Study

Physiology of cardiac tamponade and paradoxical pulse in conscious dogs

Discussion

Member takes

Implication

Key Points

Structured PICO

Main Result

Cite This Study

Also Consider

Also Consider