Stories about: heart disease

Tissue models of heart disease provide testing ground for treatments

Pink heart circuit board EKG-shutterstock_322058528Scientists are now able to create cardiac heart muscle cells from patients with heart disease. But cells alone aren’t enough to fully study cardiac disorders — especially rhythm disorders that require the activity of multiple cells assembled into tissues.

William Pu, MD, of Boston Children’s Hospital’s Heart Center and his team are honing the art of modeling heart disease in a dish. With an accurate lab model, they hope to test drug therapies without posing a risk to living patients (or even live animals).

Together with researchers at Harvard’s Wyss Institute, Pu’s lab recently modeled a rare rhythm disorder called catecholaminergic polymorphic ventricular tachycardia (CPVT). CPVT is a dangerous disease in which the heart’s rhythm can suddenly jolt abnormally without warning. Undetectable on a resting electrocardiogram (EKG), CPVT does not affect patients at rest. However, exercise or emotional upset trigger high levels of adrenaline, which can lead to life-threatening arrhythmia, cardiac arrest and possibly sudden death.

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What can pulse pressure teach us about pediatric obesity?

pulse pressure
Subtract 68 from 100 to get a pulse pressure of 42 (Wikiphoto/Creative Commons)

Second in a two-part series on cardiovascular prevention in children. Read part 1.

Carrying too much weight is tough on the body. The dramatic rise of obesity in recent years means more and more people are confronting increased cardiovascular risk due to changes in their blood vessels, cholesterol levels, blood pressure, and blood sugar. And the problem isn’t limited to adults: Today, there are more than three times as many obese children in the U.S. than there were in the early 1970s.

However, not every person with excess weight has cardiac risk factors, and not everyone with cardiac risk factors carries excess weight. So what is the relationship between childhood obesity and cardiac risk factors later in life? What links excess weight to its consequences?

Justin Zachariah, MD, MPH, a cardiologist at Boston Children’s Hospital, was inspired to investigate these “risk factors of risk factors” when he observed a pattern in his pediatric preventive cardiology clinic. He noticed that many of his patients who were carrying excess weight did not have very high blood pressure, or hypertension.

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Can simulation data guide heart disease screening in childhood cancer survivors?

Adult undergoes echocardiography guidelines for screening childhood cancer survivors for heart diseaseThe drugs and treatments developed over the last 50 years have transformed many childhood cancers from death sentences into largely curable diseases. However, those same drugs and treatments can have lasting or late effects on many different organ systems.

Such is the case with anthracyclines: Patients treated with these chemotherapy agents have a greatly elevated future risk of congestive heart failure (CHF).

For this reason, the Children’s Oncology Group (COG)—which brings together pediatric cancer experts from around the globe—currently recommends screening childhood cancer survivors with echocardiography every year or two, depending on their level of anthracycline exposure, for signs of asymptomatic left ventricular dysfunction (ALVD). If left untreated, this clinically silent condition can progress to congestive heart failure.

But are we screening the right survivors at the right times using the right methods? Answering that question for cancer and CHF would require prospectively studying thousands of survivors (itself a challenge, given childhood cancer’s relative rarity) for decades, which is neither financially nor logistically feasible.

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PVNH: Could this genetic disorder have a ‘butterfly’ effect?

butterflyThe butterfly effect is defined as “the sensitive dependence on initial conditions, where a small change at one place in a deterministic nonlinear system can result in large differences to a later state.” In medicine, the identification of a rare disease or a genetic mutation may provide insights that spread well beyond the initial discovery.

And in genetics, scientists are learning just how widespread the effects are for mutations in one gene: filaminA (FLNA).

FLNA is a common cause of periventricular nodular heterotopia (PVNH), a disorder of neuronal migration during brain development. The syndrome was first described by the late Peter Huttenlocher, MD, and the gene was identified by Christopher Walsh, MD, PhD, of Boston Children’s Hospital.

In normal brain development, neurons form in the periventricular region, located around fluid-filled ventricles near the brain’s center, then migrate outward to form six onion-like layers. In PVNH, some neurons fail to migrate to their proper position and instead form clumps of gray matter around the ventricles.

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8 steps to succeed at a risky medical “first”

James Lock, MD, Cardiologist-in-Chief, Children's Hospital Boston

Ever since second grade, when he was suspended from school, Jim Lock has challenged the status quo — in sixth grade pulling off the much harder feat of being expelled. Today, the Cardiologist-in-Chief at Children’s Hospital Boston is credited with a long list of pioneering cardiac procedures going back to 1979, many of them in children with congenital heart defects. More recently, these have included fetal interventions, like reversal of hypoplastic left heart syndrome and implanting a stent in a fetal heart. Nearly all are now established procedures in pediatric cardiology.

These procedural innovations didn’t arise from a rare flash of inspiration, Lock argues, but from perception of a medical need followed by methodical vetting and sometimes years of due diligence.

“Innovation is not a completely random event,” Lock told the Innovators’ Forum at Children’s last week, sponsored by the Innovation Acceleration Program.  “It’s a process.”

Here’s Lock’s instruction set for safe and successful clinical firsts:

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Heart disease in childhood cancer survivors: Helping keep their hearts healthy

Survivors of childhood cancers may walk around with treatment-related heart damage for decades without knowing it. Ming Hui Chen wants to help these survivors keep their hearts healthy. (qthomasbower/Flickr)

Our success at treating children with cancer has steadily improved in the 40 years since President Nixon announced the War on Cancer. At the time, 3 in 10 children survived a diagnosis of cancer; now upwards of 8 in 10 do. The U.S. alone is home to an estimated 328,000 childhood cancer survivors today.

But as these survivors age, they can experience late effects, long-term medical complications of the very treatments that saved their lives. In fact, 30 years out, survivors are at more risk of dying from treatment-related illness than from cancer recurrence.

Perhaps the most insidious late effect – and the leading cause of non-cancer death at the 30-year mark – is cardiovascular disease.

Treatment-related heart damage can take decades to appear. This long latency means that a woman treated for cancer at age 6 could face a heart attack when she’s 36. And she might never see it coming. “A survivor can walk around for years with minimal symptoms while their cardiovascular disease silently progresses,” says Ming Hui Chen, an adult cardiologist at Children’s Hospital Boston.

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