Dr. Alexander Quinn

Dr. Alexander Quinn

Dr. Alexander Quinn

Cardiovascular

Tapping into a feedback loop: Dr. Alexander Quinn seeks mechanical solutions to electrical problems in the heart

There are many different kinds of arrhythmias - irregular heartbeats - that canlead to problems from dizziness and fatigue to heart failure and sudden death. Dr. Alex Quinn is looking for effective new ways to regulate arrhythmias, by  studying how the mechanical function of the heart impacts its electrical activity—and vice versa.

"Arrhythmias are caused by disturbances in the electrical activity of the heart, but the underlying problem is often mechanical," notes Dr. Quinn, a biomedical engineer who joined Dalhousie Medical School from the University of Oxford and Imperial College in London, U.K., in 2013. "For example, if a person has high blood pressure, this can stretch the chambers of the heart and make it beat faster."

By the same token, electrical disturbances can cause mechanical problems, which in turn feed back to the electrical system, driving the progression of disease. "If you have scarring after a heart attack, for example, this will disrupt the transmission of electrical signals in the heart," Dr. Quinn explains. "The heart becomes less efficient and has to work harder to move the blood, causing the tissues to either stiffen or stretch. These mechanical changes interfere even further with the electrical signals. Eventually you end up with heart failure."

To date, there has been little success managing arrhythmias with drugs. Current treatments range from electrical devices like implantable pacemakers and defibrillators, to invasive procedures like catheter ablation and surgery. Dr. Quinn wants to open the door to new therapeutic possibilities by targeting mechanical processes in the heart.

"Learning how the heart's mechanics influence its electrics could lead the way to potential new drug strategies or a new generation of devices that target the heart's mecahnical activity," says Dr. Quinn, who collaborates with Dr. Rob RoseDr. Susan HowlettDr. Frank Smith and others at Dalhousie Medical School. "This is an area that has not been well-studied but offers a wealth of possibilities."

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