Increased Heart Stiffness May Predict Worse Prognosis in Systemic Sclerosis Patients, Study Suggests

Patients with systemic sclerosis (SSc) are more likely to experience stiffness in the right atrium, or upper chamber, of the heart, which is significantly linked to worse functional capacity, a study suggests.

Results revealed that other right atrium features related to its capacity to fill and empty may also be impaired in these patients.

The study, “Relation of Right Atrial Mechanics to Functional Capacity in Patients With Systemic Sclerosis,” was published in The American Journal of Cardiology.

People with systemic sclerosis commonly experience heart problems, resulting in a poorer prognosis.

Although abnormalities in the ventricles — the two lower chambers of the heart — are a frequent problem, new data suggests that SSc patients may also experience impairments in the right atrium. This is the right upper heart chamber that receives oxygen-poor blood returning from tissues and passes it to the right ventricle so it can pump the blood back to lungs where it is oxygenated.

Using a new technique called 2D speckle tracking echocardiography, researchers investigated what type of right atrial abnormalities can be found in SSc patients and how they correlate with patients’ functional capacity.

Speckle tracking is a new noninvasive imaging technique of the heart based on the use of ultrasound. Similar to tissue Doppler imaging, it allows researchers to determine the heart’s wall motion velocities, or myocardial heart muscle velocities, and the heart’s stiffness, among many other parameters. These parameters provide important insights about the heart’s mechanics and its capacity to pump and fill with blood.

Using speckle tracking, researchers compared the heart parameters of 70 SSc patients with those of 25 healthy volunteers, recruited from a tertiary center of the Department of Rheumatology and Immunology at the University of Pécs in Hungary.

SSc patients with pulmonary arterial hypertension and heart diseases including atrial fibrillation, significant left-sided valvular disease, and peripheral artery disease were excluded.

Functional exercise capacity of the patients was assessed by the six-minute walk test on the day of the echocardiographic measurements.

From all the heart parameters measured, right atrium reservoir strain, which measures the right atrium’s capacity to fill with blood, and conduit strain, which measures its ability to empty the blood out to the ventricle, were significantly lower in the SSc population.

Reservoir strain mean levels were 49.3% in SSc patients versus 59.6% in controls, while conduit strain mean values were 26.8% versus 34.3%.

Right atrium stiffness, defined as the change in pressure required to increase the volume of the atrium, was also significantly increased among patients, compared with controls.

However, dysfunctions in the right ventricle’s capacity to pump, called systolic function, were present but rare among SSc patients.

One of the study’s main findings was that increased right atrium stiffness and, to a lesser extent, a thicker right ventricle wall were significant predictors of worse functional capacity in SSc patients.

Based on the data, the researchers say that, for now, it is difficult to pinpoint the factors that contribute to the heart’s right atrial impairments seen in SSc patients.

The study, however, “suggests that speckle tracking-derived RA [right atrial] stiffness is a useful parameter of the RA function which has a strong influence on the functional capacity in patients with SSc,” according to the researchers. 

“Further evaluation of RA stiffness is required to verify whether this parameter is able to identify patients with subclinical elevation of pulmonary vascular resistance and to elucidate its prognostic value in SSc patients,” they concluded.