CRT in HF Boosts Ventricular Function, Whether Right or Left

March 18, 2013

SAN FRANCISCO — In the literature it's sometimes called "the forgotten chamber," after a 1995 publication on "the importance of the right ventricle"[1]. Right ventricular (RV) function isn't much considered in discussions of cardiac resynchronization therapy (CRT), but just as it contributes to global cardiac function, it also seems to benefit from device therapy aimed at cardiac function.

In a single-center observational study, RV function improved along with left ventricular function among patients randomized to CRT who, at one center, underwent serial radionuclide right ventriculography[2].

Ventricular resynchronization and reduced mitral regurgitation with improved pulmonary artery pressures may have all contributed to gains in RV systolic and diastolic function with CRT, Dr Girish Dwivedi (University of Ottawa Heart Institute, ON) speculated for heartwire . He presented the analysis here last week at the American College of Cardiology 2013 Scientific Sessions .

The patients were not specially selected for right ventriculography, he said; such scans are routinely included in their heart-failure workups at his center.

Dr Girish Dwivedi

Dwivedi and his colleagues identified 76 patients who received a CRT device with baseline and follow-up RV scans. They were compared with 76 patients who received defibrillator-only implants and were matched for age, sex, LV function, and heart-failure etiology; three-fourths of patients in both groups had ischemic heart failure.

Only the CRT patients showed improvements in RV ejection fraction, end systolic volumes, and diastolic function.

Change in Measures of Right Ventricular Systolic and Diastolic Function in Cohort Followed With Right Ventriculography

Parameter CRT patients, n=76 ICD patients (control), n=76 p
Change in RV ejection fraction (%) 9.05 1.54 <0.00001
Change in RV end systolic volume (mL) 17 10 0.005
Change in RV end diastolic volume (mL) 9.65 8.75 0.93
Change in RV peak filling rate (end diastolic volume/s) 0.24 0.04 0.0003

ICD=implantable cardioverter defibrillator

Dwivedi said part of the global gains in cardiac function with CRT may well be attributed to improved RV function, which should be considered in future CRT trials, as it is also predictive of outcomes independently of LV function.

Dwivedi had no disclosures.