When 12-year-old Mateo from Madrid collapsed during a soccer game, doctors discovered he had a rare heart condition that could stop it at any moment. His diagnosis—catecholaminergic polymorphic ventricular tachycardia, or CPVT—sent his family searching for answers. Now, a breakthrough by scientists in Spain and Italy offers new hope for children like Mateo. Researchers have uncovered a hidden chain reaction in heart cells that worsens this inherited arrhythmia, and they’ve found a way to stop it in mice—by blocking a single enzyme.
CPVT is a silent threat, often striking young people with no prior symptoms. During exercise or stress, their hearts can spiral into dangerous rhythms, leading to fainting or sudden cardiac arrest. One form of the disease is caused by a tiny glitch in a gene called CASQ2, which makes a protein that helps manage calcium in heart cells. Calcium is what powers every heartbeat, and when its flow goes awry, so does the heart’s rhythm.
At the Centro Nacional de Investigaciones Cardiovasculares (CNIC) in Madrid, Dr. Enrique Lara-Pezzi and his team, working with Dr. Silvia G. Priori from the University of Pavia and IRCCS Istituti Clinici Scientifici Maugeri in Italy, dug deeper. They studied mice with the same CASQ2 mutation found in some CPVT patients. What they found was unexpected: the mutation doesn’t just disrupt calcium—it triggers a destructive cleanup crew inside the cell. The enzyme calpain, normally involved in cell maintenance, goes into overdrive and starts breaking down vital proteins, including one called triadin, which helps keep the heart’s calcium system stable.
"Degradation of triadin actually comes before the loss of the mutant protein itself," explains Dr. Laura Ramos-Hernández, the study’s first author. "It’s a cascade—we’re seeing a sequence no one knew existed." But when the team gave the mice a calpain-blocking drug, the results were striking. The heart cells regained their balance, calcium flow improved, and dangerous arrhythmias dropped by 70%. The treated mice were far less likely to develop sustained ventricular tachycardia when stressed.
This discovery, published in Circulation Research, shifts how scientists understand CPVT. It’s not just a problem of faulty proteins—it’s also about the cell’s response to them. And by targeting calpain, doctors may one day have a way to slow or even stop the disease’s progression. While the treatment is not yet ready for humans, the findings open a new path for drug development. The team now wants to explore whether this mechanism plays a role in other forms of CPVT and even broader heart conditions.
For families living in fear of the next adrenaline rush—a sprint, a scare, a laugh too loud—this research is a quiet beacon. Science is moving closer to turning a life-threatening glitch into a manageable condition.