Atrial fibrillation (AF) is a heart rhythm disorder with an irregular and rapid heartbeat. Research is focusing on the role of calcium leakage from the sarcoplasmic reticulum (SR) in causing AF. Accurate measurement of this leakage is essential for understanding its role in the condition and for developing new treatments. A recent study used a new imaging technique to measure total SR Ca²⁺ leakage in atrial myocytes (heart muscle cells).
The study’s method involved:

1. Using a fluorescent calcium indicator and confocal microscopy to image atrial myocytes and capture high-speed line-scan images along their length.
2. Analyzing the images to extract Ca²⁺ signal components by accounting for background noise with a modified Gaussian distribution.
3. Calculating two new parameters, Fsignals and Rsignals, which represent total signal fluorescence and the fluorescence during the signal’s rising phase, respectively.

Key findings:

50. Fsignals and Rsignals are strongly associated with traditional measures of SR Ca²⁺ leakage.
50. These parameters can distinguish between normal and mutant atrial myocytes, suggesting increased Ca²⁺ leakage in the mutant group.

The work entitled “Assaying sarcoplasmic reticulum Ca²⁺-leak in mouse atrial myocytes” was published on Biophysics Reports (published on February, 2024).
DOI: 10.52601/bpr.2023.230044