What does this research mean for the field?

In uniform anisotropic ventricular myocardium, reentrant ventricular tachycardia is initiated because premature beats lower the stimulating efficacy of the depolarization wave, leading to preferential conduction block parallel to the fiber orientation. Novelty: ClaimNovelty.NOVEL_FINDING. Consensus alignment: ConsensusAlignment.NEUTRAL.

What question did this study set out to answer?

This study aims to understand how tissue anisotropy and refractoriness affect the initiation of reentrant ventricular tachycardia.

September 1, 1991CirculationOpen Access

Reentrant excitation around a fixed obstacle in uniform anisotropic ventricular myocardium.

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This study aims to understand how tissue anisotropy and refractoriness affect the initiation of reentrant ventricular tachycardia.
Created a ring of perfused uniform anisotropic ventricular epicardium using an endocardial freezing technique.
Used high-resolution mapping (248 channels) to analyze epicardial activation in Langendorff-perfused rabbit hearts.
Induced 1 to 3 premature beats at 272 points in 17 experiments to assess reentrant VT initiation.
Reentrant VT was initiated at 43 of 272 tested points.
Cycle length of VT ranged from 128 to 198 msec, with a mean of 161 +/- 19 msec.
Average conduction velocity was significantly faster (60 +/- 7 cm/sec) parallel to fiber orientation compared to perpendicular (25 +/- 5 cm/sec).

Structured PICO

Population

Langendorff-perfused rabbit hearts with a ring of perfused uniform anisotropic ventricular epicardium created by an endocardial freezing technique (n=17 experiments)

Intervention

Induction of one to three premature beats at 272 points (16 different points around the ring in each experiment)

Outcome

Initiation of reentrant ventricular tachycardia (VT), conduction velocity, site of unidirectional conduction block, and refractory periodssurrogate

In uniform anisotropic ventricular myocardium, reentrant VT is initiated due to preferential conduction block parallel to the fiber orientation caused by premature beats.

Discussion

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Implication

Anisotropic block may initiate reentry in uniform myocardium; leaves open whether this mechanism drives clinical VT in humans.

Cite This Study

Brugada et al. (1991) studied this question.

synapsesocial.com/papers/6a1bcce15b8f4ede65a90ee5 https://doi.org/10.1161/01.cir.84.3.1296

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Reentrant excitation around a fixed obstacle in uniform anisotropic ventricular myocardium.

Key Points

Structured PICO

Discussion

Implication

Cite This Study

Reentrant excitation around a fixed obstacle in uniform anisotropic ventricular myocardium.

Key Points

Structured PICO

Discussion

Implication

Cite This Study

Also Consider

Also Consider