Smoking can be called a deadly habit as it not only harms smokers, but also the people around them. Second hand smoking is increasingly becoming a major public safety concern with studies blaming second hand smoking for a number of healh issues including irregular heartbeats.
Researchers have shown the continuous indoor exposure to second-hand tobacco smoke can trigger changes in the heart’s electrical activity thereby causing irregular heartbeat. The study was carried out in mouse model and findings have been published in the journal Environmental Health Perspectives.
This study is the first to examine cellular changes in heart tissue in response to ambient tobacco smoke, researchers said. Another novel thing about the study is that it is focused on a heart condition other than coronary artery disease (CAD), or plaque buildup and vessel hardening associated with lifestyle and age.
For the study researchers exposed mice to secondhand tobacco smoke in a chamber specifically designed to test health effects associated with inhaled toxins. The smoke levels were set to be similar to those found in public areas where smokers are present. Following four, eight and 12 weeks of exposure for six hours a day, five days a week, the animals’ hearts were tested using high-speed imaging and electrocardiograms for changes in electrical activity.
To test susceptibility to arrhythmias, hearts were paced at fast heart rates. They also were tested for levels of calcium, which regulates heart contraction and contributes to abnormal rhythms. The results were compared to hearts of mice exposed only to filtered air. The researchers found that hearts from mice exposed to filtered air responded normally, but the hearts from mice exposed to secondhand smoke could not tolerate fast rates, especially at 12 weeks of exposure. They also found that calcium levels in these hearts did not respond quickly enough, causing beat-to-beat instability, or cardiac alternans.