ZebraPace: An Open-Source Method for Cardiac-Rhythm Estimation in Untethered Zebrafish Larvae

Area of Science:

• Cardiovascular Research
• Developmental Biology
• Bioimage Analysis

Background:

• Cardiac function assessment is crucial in biological research.
• Existing zebrafish heartbeat measurement methods are complex, costly, and require specialized equipment or skills.
• There is a need for accessible, efficient tools for analyzing cardiac rhythm in zebrafish.

Purpose of the Study:

• To introduce ZebraPace, a novel, user-friendly method for quantifying zebrafish larval heartbeat.
• To provide a cost-effective and accessible alternative to current complex heartbeat analysis techniques.
• To validate the accuracy and reliability of ZebraPace for cardiac function assessment.

Main Methods:

• Developed ZebraPace, an ImageJ-based algorithm for analyzing cardiac rhythm in untethered, unlabeled zebrafish larvae.
• Utilized pixel intensity changes in grayscale AVI videos for beat counting, requiring no image processing.
• Validated ZebraPace by assessing pharmacological effects on heartbeat in 48 and 72 hours post-fertilization (hpf) zebrafish.

Main Results:

• ZebraPace accurately measures heartbeat rate and beat-to-beat interval in zebrafish larvae.
• Results from ZebraPace correlate well with established methods and literature values.
• The method demonstrates effectiveness in detecting pharmacological alterations in cardiac rhythm.

Conclusions:

• ZebraPace offers a simple, cost-effective, and objective approach to zebrafish cardiac function analysis.
• The method reduces manual labor, sample preparation time, and researcher subjectivity.
• ZebraPace is a valuable tool for researchers studying cardiovascular development and function in zebrafish.