Washington, Oct 21 (IANS): Two Indian-origin high school students Ilina and Medha Krishen have developed screening tools to detect lung and heart disease using electronic stethoscopes.

Curious to find a way to detect early lung damage in people exposed to noxious air pollutants, the sister duo from Port Huron Northern High School, Michigan in the US, developed a screening mechanism using an electronic stethoscope.

An electronic stethoscope overcomes the problem of low sound levels by electronically amplifying body sounds.

"When I was in fifth grade, a family friend died after exercising and I always wanted to learn more about how to prevent something like that happening," Medha said.

"My study analysing heart sound frequencies may be a useful technique that school staff could use to screen for hypertrophic cardiomyopathy (HCM)," she added.

For her study, Medha studied 13 athletes: 10 with normal hearts and three diagnosed with HCM.

Heart sounds were recorded in five-second periods while the athletes were lying down, standing and after exercise.

Frequency peaks of a frequency amplitude plot were analysed.

Studies showed a significant difference in the distribution of frequency peaks in the two groups between the lying down and after exercise positions.

"Normal athletes showed a lower percentage of peaks above 131 Hz after exercise, while the athletes at risk showed a rise in frequency peaks following exercise," said Medha.

Ilina, on the other hand, recruited 16 smokers, 13 firefighters, and 25 non-smokers for her test.

She used the electronic stethoscope to record one breath cycle from each volunteer and frequency peaks were used to analyze the frequency distribution of breath sounds.

Ilina found that the number of peaks was significantly higher in smokers and firefighters, even if the firefighters were non-smokers.

"The firefighters are exposed to many poisonous chemicals that remain in the air after the fire has gone out. Screening with an electronic stethoscope may be able to detect changes in lung function in individuals without symptoms of lung disease," she concluded.

The sisters are scheduled to present their findings at CHEST 2014, the annual meeting of the American College of Chest Physicians in Austin next week.