Smoking cigarettes is becoming less common in everyday society, yet both firsthand and secondhand exposure to tobacco smoke are still responsible for creating numerous health issues. There has been a lack of research in the problems associated with exposure to secondhand smoke, as most research tends to focus more on the effects of firsthand smoke. A new research study from UC Davis Health investigated the effects of exposure to secondhand smoke on cardiac tissue.
The research team exposed mice to secondhand smoke for four, eight, and 12 weeks and then analyzed cardiac function through the use of electrocardiograms and calcium measurements. The electrocardiogram visualizes the electrical conductivity of the heart and is most commonly used in order to detect the presence of cardiac arrhythmias, improper heartbeats that lead to damage of the heart over time. Calcium is important in the contraction of cardiac tissue; therefore, calcium imbalances in cardiac tissue can lead to the development of cardiac arrhythmias. The results from the mice exposed to tobacco were compared to control mice that were exposed to filtered air for the same amount of time. Mice with longer exposures to tobacco (12 weeks only) showed deficiencies in the intracellular release of calcium that could not respond to and sustain fast-paced heartbeats, leading to the development of cardiac alternans. The delay in the release of calcium prevents the heart from being able to contract uniformly and leads to additional contractions being introduced, making the heart work harder. These alternans can be visualized through an electrocardiogram and will most commonly be seen as a new peak on the electrocardiogram read out in a location separated from the main peaks.
Image Source: Luis Diaz Devesa
These findings are important as the presence of cardiac alternans can arise to further complications down the line. Cardiac alternans, if not detected, most commonly develop into cardiac arrhythmias, which can lead to cardiac stress and the onset of sudden cardiac death (SCD). In addition, people most commonly associate secondhand smoke exposure with the lungs since it is known that secondhand smoke exposure can lead to the development of lung cancer. It is important for research in this field to be conducted in order to allow people to be more informed about the dangers associated with smoking and develop a more complete understanding of this carcinogen that can lead to numerous diseases throughout the body.
Feature Image Source: Claire Dela Cruz
