January 1, 1978Circulation Research
The role of canine superficial ventricular muscle fibers in endocardial impulse distribution.
Population
Canine right and left ventricular endocardium and myocardium preparations (n=12)
Comparison
Electrophysiological and histological evaluation… vs Comparison between Purkinje fibers, superficial…
Design
Preclinical
Authors
Discussion
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Implication
SVM geometry enables intermediate subendocardial conduction; extends prior observations but leaves human arrhythmia relevance untested.
Key Points
- To compare the conduction characteristics and fiber orientation of Purkinje fibers, superficial subendocardial ventricular muscle, and deep ventricular muscle in canine ventricles.
- Mounted thin tissue sections of canine right and left ventricular endocardium and myocardium in an isolated tissue bath across 12 preparations.
- Conducted electrophysiological and histological examinations, utilizing localized endocardial stripping to isolate deep ventricular muscle and measure intrinsic conduction velocity.
- Calculated average conduction velocity was 1.62 m/sec in Purkinje fibers, 0.26 m/sec in deep ventricular muscle, and 0.98 m/sec in superficial ventricular muscle parallel to fiber orientation.
- Conduction velocity transverse to superficial ventricular muscle fibers did not differ significantly from deep ventricular muscle velocity.
- Histological analysis demonstrated uniform longitudinal alignment of superficial ventricular muscle fibers parallel to the direction of rapid conduction, whereas deep muscle fiber orientation varied.
Structured PICO
P
Population
Canine right and left ventricular endocardium and myocardium preparations (n=12)
I
Intervention
Electrophysiological and histological evaluation of conduction properties
C
Comparator
Comparison between Purkinje fibers (PF), superficial layers of subendocardial ventricular muscle (SVM), and deeper ventricular muscle (DVM)
O
Outcome
Conduction velocitysurrogate
The geometric arrangement of superficial ventricular muscle fibers provides a means for rapid subendocardial conduction at a velocity intermediate between Purkinje fibers and deeper ventricular muscle.
Cite This Study
Myerburg et al. (1978) studied this question.