Semi-automated Optical Heartbeat Analysis of Small Hearts

Summary

We have developed a Semi-automated Optical Heartbeat Analysis method (SOHA) for analyzing high speed optical recordings from Drosophila, zebrafish and embryonic mouse hearts. We demonstrate the application of our methodology to the analysis of heart function in fruit fly and embryonic mouse hearts.

Abstract

We have developed a method for analyzing high speed optical recordings from Drosophila, zebrafish and embryonic mouse hearts (Fink, et. al., 2009). Our Semi-automatic Optical Heartbeat Analysis (SOHA) uses a novel movement detection algorithm that is able to detect cardiac movements associated with individual contractile and relaxation events. The program provides a host of physiologically relevant readouts including systolic and diastolic intervals, heart rate, as well as qualitative and quantitative measures of heartbeat arrhythmicity. The program also calculates heart diameter measurements during both diastole and systole from which fractional shortening and fractional area changes are calculated. Output is provided as a digital file compatible with most spreadsheet programs. Measurements are made for every heartbeat in a record increasing the statistical power of the output. We demonstrate each of the steps where user input is required and show the application of our methodology to the analysis of heart function in all three genetically tractable heart models.

Protocol

Click here to view an overview of the semi automated heartbeat analysis (SOHA) procedure.

Semi-automated optical heartbeat analysis

1. Preprocess -

This step provides information on the diastolic and systolic heart diameters.

Heart edges are identified and marked during maximum diastole and systole. Optical recordings can be advanced at slow speeds and even one frame at a time allowing precise identification of the frames where maximal contraction and relaxation of the heart occur. One ....

Discussion

The Drosophila model has proven to be a powerful genetic tool that has been used to address a variety of scientific questions ranging from embryological development to learning and memory. Recently this versatile model organism has been used to investigate the genetics of heart function. A number of attempts to quantify heart physiology in adult Drosophila have relied on observations made in intact flies through the abdominal cuticle. Most of these approaches depend upon visual observation or recordings of changes in li.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
MatLab software	Mathworks		Required environment for the analysis software.
EM-CCD digital camera	Hamamatsu Corp.	9100 or 9300	Other high speed digital cameras will also work.
HC image data capture software	Hamamatsu Corp.		Other image capture software that produces movies in avi format will also work.
Light Microscope with 10x objective	Leica Microsystems		A dipping lens that eliminates the air water interface greatly improves resolution