How does obesity affect heart health over the entire life span?

By tracking the impacts of obesity across the entire lifespan, this research project aims to enable earlier detection and treatment of cardiovascular disease to improve health outcomes and help save lives. 

How early in life does obesity start to affect cardiovascular health? The answer to this important question is currently being investigated by Dr Faraz Pathan, a cardiologist and Director of Cardiovascular Imaging and Heart Research at Nepean Hospital. Pathan is studying when changes can be measured in cardiovascular health at different ages, from before birth and across the entire life span. This research will help to determine how obesity affects the heart health of adults, adolescents and also the foetus (if the mother has obesity and diabetes during pregnancy).  

This work has been supported by a NSW Health Cardiovascular Early Mid-Career Researcher Grant awarded by the Office for Health and Medical Research in 2010. “The grant has enabled our team to build a cardiometabolic research program at Nepean hospital and involve PhD students working in areas such as cardiology, intensive care and exercise physiology,” says Pathan. 

Tracking cardiovascular impacts of obesity 

One out of three Australians (around 12.5 million people), are classified as living with overweight or obesity. “Studies show that in the long-term, obesity can lead to cardiac health problems including heart attacks, heart failure and irregular heart rhythms,” says Pathan. “My research aims to help prevent those heart problems by detecting and addressing cardiac impacts of obesity earlier and at every life stage.” 

Finding participants for this research has involved ongoing collaboration with health services in the Nepean Blue Mountains Local Health District. Recruitment of patients has involved pediatric and endocrinology specialists, bariatric surgeons, local GPs, hospital staff and medical students. “We have also been very fortunate to work with the Nepean Blue Mountains Family Metabolic Health Service,” says Pathan. “At the department of perinatal ultrasound at Nepean Hospital, an excellent sonographer recruited the pregnant women involved in our study and conducted scans during their pregnancy. By looking at early life changes in unborn babies we can evaluate the medical ‘buttery fly effect’, to determine how very small differences in life may impact future heart events.” 

Heart strain and future heart health 

Heart strain due to obesity can cause changes to the size of the atria (upper chambers) and ventricles (lower chambers) of the heart, which receive and pump blood. As these changes may be one of the earliest signs of heart impacts from obesity and weight gain, Pathan and his team have been screening study participants to detect heart strain. To do this they have used echocardiography, which forms images using sound waves that show the structure and function of the heart. “The scans are a little like using a crystal ball,” Pathan explains. “The higher the indicators of atrial and ventricular heart strain in the heart’s chambers, the greater the likelihood that the person may experience future cardiovascular events such as heart failure or irregular heart rhythms.” 

The presence of heart strain can predict deterioration of heart function before symptoms of disease manifest obviously in the body. It also enables measures to be taken sooner to help prevent or reduce severity of cardiovascular disease. “These measures may include targeted efforts to lose weight and improve lifestyle habits, including use of weight loss medication and weight loss surgery,” Pathan explains. “Using echocardiography to check the heart of unborn babies, we have identified that some babies whose mothers have Type 1, Type 2 and gestational diabetes, show abnormalities in their heart patterns as early as 24 weeks in the womb.”  

Checking cardiac blood flow and function  

Pathan’s research has also been drawing on hemodynamics, which is the study of how blood flows through blood vessels. “We have been using hemodynamic tests such as Magnetic Resonance Imaging scans to look at how efficiently the heart is pumping blood around the body,” Pathan says. These scans use magnetic field and radiofrequency waves to create detailed images of the heart. “This is helping us to assess how efficiently blood cells travel from one chamber of the heart to another,” Pathan adds.  

Cardiac Magnetic Resonance Imaging allows the team to see the size and function of heart chambers in patients who may have been affected by obesity. “For this reason, it is the gold standard approach for examining heart volume and function,” says Pathan. “By tracking heart changes and cardiac function in people of different ages, our research aims to assist earlier medical intervention. Long-term, we hope this will improve the heart and overall health and quality of life of those impacted by obesity, whether they are a baby, a teenager or an adult.”