DENVER—Left ventricular (LV) leads positioned in the apical region when compared to the mid-ventricular or basal regions are associated with a significantly increased risk of heart failure (HF) and death in patients receiving cardiac resynchronization therapy (CRT), according to a late-breaking clinical trial presented today at the Heart Rhythm Society’s 31st annual scientific sessions.
Lead author Jagmeet P. Singh, MD, PhD, from Massachusetts General Hospital in Boston, said that this substudy of MADIT-CRT is the first trial to evaluate clinical outcomes based on the LV lead position within a mildly symptomatic CRT patient population.
In the MADIT-CRT trial, patients were randomly assigned to receive CRT-D or implantable cardioverter-defibrillator (ICD) therapy. A total of 1,820 patients were enrolled in 110 centers, and 25 percent of the patient population were women. The results of the MADIT-CRT study showed that over a two-year follow-up period, CRT-D was associated with a 34 percent overall reduction of death and HF in minimally symptomatic patients, and that CRT-D was more effective in women than men.
According to Singh, this sub-study of MADIT-CRT sought to evaluate the impact of LV lead location on outcomes in 799 patients randomized to CRT-D. The researchers classified the LV lead location along the short axis into an anterior, lateral or posterior position, and along the long axis into a basal, mid-ventricular or apical region. They analyzed the location of the left ventricle lead by a core-lab review of coronary venograms and chest x-rays recorded at the time of device implantation.
Results showed that 22 percent of patients with apical lead position had a significantly increased risk of HF and mortality compared to an average of 12 percent for patients with the mid-ventricular or basal position.
The placement of LV leads along the anterior, lateral or posterior wall in CRT-D patients showed similar outcomes and extent of benefit from resynchronization therapy.
He also reported: “Patients with ischemic cardiomyopathy, a wider QRS, a lower ejection fraction and a larger heart actually had worse outcomes as compared with patients who had an apical lead position than those with a non-apical lead position.”
When the researchers separated out the endpoints to only examine death for apical versus non-apical positioning, they found an approximately three-fold increase in death for the leads located in the apical region.
He concluded that the benefit of CRT was similar for anterior, lateral and posterior wall positions, and similar for mid-ventricular and basal lead positions.
In his response to the trial, Michael R. Gold, MD, PHD, Medical University of South Carolina in Charleston, noted that these findings are contrary to some previous findings.
However, based on their findings, Singh reported that apical lead position location alone was independently associated with an increased risk of heart failure and death.
It was “surprising,” according to Gold, that there was no difference in anterior versus posterior versus lateral positions, with only the apical being associated with worse outcomes. “The anterior lead position [in Singh et al’s study] held up much better than we would have expected,” Gold said.
“We can look back at patient groups who may not have previously responded positively to CRT and consider alternate lead positions,” Singh said. “These findings could also enhance the overall response rate to CRT for future patients by simply avoiding the apical position altogether.”
Based on this study and others, Gold noted the positioning is “much more complicated than we have thought in the past.”
Singh concluded that the most important take-home message is that LV leads positioned in the apical region are associated with unfavorable outcomes, and should be avoided.