A breakthrough study conducted by Dr. Hesham Sadek, director of the Sarver Heart Centre at the University of Arizona College of Medicine - Tucson, finds that a fraction of mechanical heart patients can repair heart muscle, raising hopes for new treatments and possibly a cure for heart failure. The findings, published in Circulation, are a crucial step towards better understanding the regenerative ability of human heart tissue. 

Heart failure, which affects approximately 7 million adults in the United States and causes 14% of all deaths each year, has long been thought to be incurable. Medications used now are meant to slow the disease's progression, but patients who are too far along need heart transplants or left ventricular assist devices (LVADs). LVADs, often known as artificial hearts, assist in blood pumping when the heart no longer functions properly. 

Dr. Sadek underscored the heart's limited ability to regenerate compared to skeletal muscle, asserting that an injured heart muscle does not regenerate. We don't have anything that can reverse cardiac muscle loss." 

The multinational study team worked with Dr. Stavros Drakos of the University of Utah and experts from the Karolinska Institute in Sweden, including Dr. Jonas Frisén and Dr. Olaf Bergmann. Using novel carbon-dating techniques, the researchers showed that artificial heart patients repair muscle cells at a rate over six times that of healthy hearts. 

"This is the strongest evidence we have so far that human heart muscle cells can actually regenerate," Sadek told reporters. "It solidifies the notion that there is an intrinsic capacity of the human heart to regenerate." 

The findings support the concept that the heart's continual activity after birth impairs its ability to repair. Artificial hearts appear to give cardiac muscles a "rest" period, similar to how bed rest aids skeletal muscle recovery following injury. 

Dr. Sadek's research began in 2011, when he discovered that cardiac muscle cells develop actively in the womb but stop dividing after birth. By 2014, his research revealed that certain artificial heart patients could rebuild cardiac muscle, pointing to LVADs' therapeutic potential. 

The most recent study verifies these early findings, providing conclusive proof that human heart muscle may regenerate under certain conditions. 

Despite this accomplishment, only approximately 25% of artificial heart patients see considerable cardiac muscle regeneration. Dr. Sadek and his team are now working to figure out why some patients are "responders" and others not. 

"It's not clear why some patients respond and some don't, but it's very clear that the ones who respond have the ability to regenerate heart muscle," Sadek told reporters. "The exciting part now is to determine how we can make everyone a responder, because if you can, you can essentially cure heart failure." 

Sadek emphasised the usefulness of LVADs, stating, "The beauty of this is that a mechanical heart is not a therapy we hope to deliver to our patients in the future—these devices are tried and true, and we've been using them for years." 

This groundbreaking discovery provides new hope for millions of heart failure patients. Scientists may one day discover a treatment for one of the world's most significant health issues if they can grasp the mechanics underlying cardiac muscle regeneration.