Visualization of left ventricular Purkinje fiber distribution using widefield optical coherence microscopy.

BACKGROUND: The distribution and connection of ventricular Purkinje fibers are known to be associated with idiopathic left ventricular arrhythmias. Unusual anatomy is one of the important factors associated with catheter ablation success rate. With the widefield high-speed, swept-source optical coherence microscopy (OCM) and light microscope, we visualized the left ventricular Purkinje fiber distribution. METHODS: Left ventricular walls of five adult ovine hearts were incised from the mitral annulus to the apex. Using the widefield OCM technique and light microscopy, we observed the distribution, direction, depth, and dividing patterns of the Purkinje network with multiple tangential angles and without tissue destruction. RESULTS: Widefield OCM was used to characterize the ovine heart Purkinje network system in a 4 × 4 mm2 field. Left ventricular Purkinje fibers traveled in the sub-endocardial area near the left-sided peri-membranous septal area and ran like a wide hair bundle. The distal branching fibers penetrated to the endocardium and connected to the contractile muscle. In this distal area, Purkinje fibers were connected to each other, forming multiple layers. Some Purkinje fibers were directly connected within the false tendon between the papillary muscles or between the trabeculations. Some free-running Purkinje fibers were directly connected to the papillary muscle from the left bundle. CONCLUSION: Using widefield OCM, we were able to observe the left bundle and its branching patterns in ovine left ventricle without tissue destruction. This might be applied to future cardiac ablation procedures.

Efficacy of Two-dimensional Scanning Digital Kymography in Evaluation of Atrophic Vocal Folds.

OBJECTIVE: The purpose of this study was to evaluate the clinical feasibility and diagnostic accuracy of two-dimensional scanning digital kymography (2D DKG) in patients with vocal cord atrophy before and after treatment. MATERIALS AND METHODS: We analyzed the characteristics of vocal fold vibration in five patients with unilateral vocal fold paralysis and five patients with presbyphonia. In patients with vocal cord paralysis, the status before and after intracordal injection was compared. Furthermore, in patients with presbyphonia, we compared the status before and after voice therapy (Seong-Tae Kim's laryngeal calibration technique). Quantitative parameters such as amplitude and phase symmetry indices, jitter, shimmer, noise-to-harmonic ratio, and maximum phonation time and qualitative parameters such as Voice Handicap Index, glottal gap, amplitude, and phase difference were used to evaluate the pre- and post-treatment status. RESULTS: In cases of vocal cord paralysis, vibratory changes of the vocal folds before and after intracordal injection could be identified immediately using 2D DKG. In overcorrection cases, all of the measured parameters were poor except for improvement of the glottal gap. In addition, 2D DKG showed appropriately the changes in vocal cord vibration before and after voice therapy in patients with presbyphonia. CONCLUSION: Two-dimensional DKG may be a useful diagnostic tool in evaluation of the vibratory characteristics of entire vocal cords. In addition, it may also play a role in providing a decision for treatment modalities.

Real-time Simultaneous DKG and 2D DKG Using High-speed Digital Camera.

INTRODUCTION: For the evaluation of voice disorders, direct observation of vocal cord vibration is important. Among the various methods, laryngeal videostroboscopy (LVS) is widely used, but it was not a true image because it collects images from different cycles. In contrast, high-speed videoendoscopy and videokymography have much higher frame rates and can assess functional and mobility disorders. OBJECTIVE: The purpose of the study is to describe real-time, simultaneous digital kymography (DKG), two-dimensional scanning (2D) DKG, and multi-frame (MF) LVS system using a high-speed digital camera, and identify the efficacy of this system in evaluating vibratory patterns of pathologic voice. METHODS: The pattern of vocal fold vibration was evaluated in a vocally healthy subject and in subjects with vocal polyp, vocal nodules, vocal cord scar, and vocal cord paralysis. We used both quantitative (left-right phase symmetry, amplitude symmetry index) and qualitative (anterior-posterior phase symmetry) parameters for assessment of vocal fold vibration. RESULTS: Our system could record videos within seconds and required relatively little memory. The speed of replay in the DKG, 2D DKG, MF LVS, and high-speed videoendoscopy was controllable. The number of frame per cycle with MF LVS was almost the same as the fundamental frequency. CONCLUSION: Our system can provide images of various modalities simultaneously in real time and analyze morphological and functional vibratory patterns. It can be possible to provide a greater level of information for the diagnosis and treatment of vibratory disorders.