DENVER — A left-ventricular lead positioned in the apical region in recipients of cardiac resynchronization therapy was associated with a significantly increased risk of death or heart failure hospitalization, compared with midventricular or basal lead positioning, in a secondary analysis of the landmark Multicenter Automatic Defibrillator Implantation Trial With Cardiac Resynchronization Therapy (MADIT-CRT).

“Based on this study we have enough data to suggest that the apical lead position is not a good place. … My take-home message would be to avoid the apical lead position if you can,” Dr. Jagmeet P. Singh said at the meeting.

An estimated 15%–20% of patients with CRT have their left-ventricular (LV) lead positioned in the apical region. Avoiding this lead position could cut down on the current overall CRT nonresponse rate of roughly 30%, added Dr. Singh, director of the CRT program at Massachusetts General Hospital, Boston.

MADIT-CRT involved 1,820 patients with minimally symptomatic heart failure, an LV ejection fraction of less than 30%, and a QRS duration of at least 130 msec, all of whom also met the standard criteria for receiving an implantable cardioverter defibrillator (ICD). They were randomized to receive an ICD only or a combined CRT plus ICD device (CRT-D).

In the previously reported main results, CRT-D was associated with a highly significant 34% reduction in the primary composite end point of death or heart failure hospitalization over 2.4 years of follow-up (N. Engl. J. Med. 2009;361:1329–38).

The new secondary analysis presented by Dr. Singh involved 799 CRT-D recipients with coronary venograms and chest x-rays obtained at device implantation. These imaging studies were analyzed in a central core laboratory to determine the LV lead position, which was apical in 14%, midventricular in 63%, and basal in 23%.

The rate of death or heart failure hospitalization during 2.4 years of follow-up was 22% in patients with the LV lead in the apical region, 14% with a midventricular location, and 10% with a basal location. The thought is that an LV lead in the apical region is placed too close to the right-ventricular lead to allow the full benefits of resynchronization to occur, the investigator explained.

In a multivariate Cox analysis, an apical lead position was associated with an adjusted 1.6-fold increased risk of death or heart failure hospitalization, compared with nonapical positioning. The apical position also was associated with a 2.6-fold increased risk of mortality.

Importantly, the MADIT-CRT analysis also showed that there was no difference in outcomes regardless of whether patients had their LV lead in an anterior, posterior, or lateral position in the midventricular or basal region. All proved superior to apical positioning, contrary to the conventional wisdom.

“Oftentimes we're constrained by the limitations of venous anatomy, but I think we now realize that some of the locations that we considered suboptimal, like the anterobasal region, are not as detrimental as an apical lead placement,” Dr. Singh continued.

Scientific Sessions Program Committee Chair Bruce L. Wilkoff predicted in an interview that this report from MADIT-CRT will have a big impact.

“This probably will change practice to some degree because it's counterintuitive to the way some people have been thinking…. It formerly had a negative connotation, but now if you have a choice between apical and anterior you're going to move the lead more anteriorly,” said Dr. Wilkoff, professor of medicine and director of cardiac pacing and tachyarrhythmia devices at the Cleveland Clinic Foundation.

The MADIT-CRT data also open the door to consideration of redo procedures with alternate lead positions in CRT nonresponders with an apical LV lead position.

“CRT is one of the few things you can do for people with bad heart failure short of transplantation. If you've done your best and it's still not working, and you've put the lead in a spot you now have reason to believe won't be very useful, you might be willing to open their chest and do other things,” Dr. Wilkoff added.

However, discussant Dr. Michael R. Gold said it's too early to give up on apical lead positioning altogether.

“There has been a drive that's almost an obsession with trying to place the lead on the LV free wall,” he observed. “The lesson learned from recent LV lead position studies is it's much more complicated than we thought. Don't abandon an implant if a good lateral wall vein isn't found. I think there are now compelling data that there are good responses with an anterior lead. There probably is no 'sweet spot,'” said Dr. Gold, professor of medicine, chief of cardiology, and medical director of the Heart and Vascular Center at the Medical University of South Carolina, Charleston.

Disclosures: MADIT-CRT was sponsored by Boston Scientific. Dr. Singh, Dr. Wilkoff, and Dr. Gold disclosed that they receive research grants from and serve as consultants to all the major implantable cardiac device companies.

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'My take-home message would be to avoid the apical lead position if you can.'

Source DR. SINGH

CRT Outcome Influenced by LV Lead Position