Measuring the twisting motion of the heart prior to mitral valve surgery predicted the outcome for some heart failure patients, a study showed.
The study looked at patients with nonischemic, chronic secondary severe mitral regurgitation (NICSMR), a group for which it's difficult to identify appropriate candidates for mitral valve replacement or repair.
The researchers examined 50 patients with the condition for a median of two-and-one-half years following mitral surgery, according to an American College of Cardiology statement. All of them exhibited advanced heart failure symptoms and had received the maximum guideline-based therapy for more than 6 months. Of the 50 patients, 19 had died after two years. The researchers found that the amount of torsion, or twisting, of the left ventricle was higher in survivors.
|Illustration of an electrocardiogram showing QRS complex (red)|
They split the patients into three groups: those with preserved left ventricular torsion, those who had lost torsion and those who had a wide QRS measurement and received cardiac resynchronization therapy. The QRS complex is a combination of three graphical points seen on an electrocardiogram.
For NICSMR patients with a narrow QRS width, preserved torsion "may be a better predictor" of surviving mitral valve surgery, while lost torsion may lead to a poor outcome, according to the statement. Patients who received cardiac resynchronization therapy before mitral surgery had "significantly worse" outcomes than those who had the procedure during mitral surgery.
While the study demonstrates that left ventricular torsion can help predict outcomes in patients with a narrow QRS width, it is less effective in those with a wide QRS measurement.
"These findings show that lost left ventricular torsion and previously administered cardiac resynchronization therapy appear to be markers of poor survival after mitral surgery in patients with NICSMR," said Dr. Yuichi Notomi from the division of cardiovascular imaging, department of cardiology at The Hayama Heart Center in Kanagawa, Japan, and the lead author of the study, in the statement.
"Mechanistically, this study suggests that the loss of torsion in patients with heart failure may reflect irreversible structural damage to the heart which would prevent the heart from recovering after corrective surgery," said Dr. Douglas Mann, editor-in-chief of JACC: Basic to Translational Science, where the study was published. "If correct, this will have much broader implications than improvement after mitral valve surgery since it may predict which patients with heart failure may get better on medications."