A study comparing recalled defibrillator leads made by St. Jude Medical (NYSE:STJ) with 1 from rival Medtronic (NYSE:MDT) found 1 St. Jude model’s survival rate to be "significantly worse."

The study, presented today at the Heart Rhythm Society’s annual meeting in Boston, examined data from 7 centers that used the 3 lead models – St. Jude’s recalled Riata and Riata ST and Medtronic’s Quattro – to calculate long-term survival rates.

Compared with the Quattro lead, the Riata’s survival rates were "significantly worse," according to co-author Dr. Rael Abdelhadi. Although the survival rate for the Riata ST was about the same as Quattro’s, the follow-up time for the Riata ST was shorter than for the Riata model, Abdelhadi told reporters this morning at the conference.

"Our data suggest that externalizations are common in dual-coil leads," Abdelhadi said.

The malfunction rate for the Riata lead was 5.6%, compared with 1.3% for the Riata ST and 1.4% for the Quattro lead. The failure rate for the Riata lead was 1.9%, compared with 0.5% for the Riata ST and 0.4% for the Quattro.

"We were unable to identify any predictors for Riata and Riata ST failures," Abdelhadi said, noting that over-sensing problems were often a pre-cursor to malfunction.

Another study published by the Heart Rhythm Society created an unprecedented furor last month, when St. Paul, Minn.-based St. Jude countered with a vociferous rebuttal. The study, by prominent cardiologist Dr. Robert Hauser, linked Riata with 22 deaths. St. Jude was quick to dispute the findings. St. Jude asked that the HRS retract the story (a request that was summarily rebuffed), and over the course of the following weekend St. Jude CEO Daniel Starks reiterated his accusation that cross-town rival Medtronic was the architect of a "whisper campaign" against the Riata lead.

Asked if he expected to receive a similarly vociferous response from STJ, Abdelhadi said discussion of such important data should be left to the peer-review process.

"These are all scientific papers that, in my mind, should be addressed in a peer-reviewed process," he told MassDevice.com. "This is data from 7 centers that … hopefully will be well-received."

Study: Cameron Health’s "leadless" S-ICD safe & effective

Results from another study presented at the HRS conference today, of a "leadless" defibrillator that’s implanted subcutaneously, found the device safe and effective for treating patients with life-threatening ventricular arrhythmias.

"This has been an exciting study," co-author Dr. Martin Burke told reporters at the conference this morning. "It’s a joy to work with [the S-ICD] and [the patients] all love it. … This particular trial demonstrated that both [safety and efficacy] endpoints were met."

The S-ICD device made by Cameron Health, which is slated for a buyout worth up to $1.35 billion by Boston Scientific (NYSE:BSX), successfully converted 100% of the ventricular fibrillations in the 304 patients who completed the trial.

The rate of major complications was 4.4% at 30 days and 7.9% after 6 months. Twenty-three patients, or 7.2%, needed repeat surgeries to correct problems such as electrode movement, device movement or discomfort. Four devices (1.2%) were pulled for infections and 2 (0.6%) underwent "premature battery depletion."

There were 8 deaths (2.5%), according to the researchers, with 1 associated with an "appropriate" shock and another unable to be defined because the device wasn’t available to examine.

The Cameron S-ICD won effusive praise from an FDA advisory panel last month, which voted 7-1 to recommend approval of the device. Unlike "transvenous" ICDs that use wires threaded through blood vessels, the S-ICD’s leads are implanted in a surgically created channel along the patient’s chest.

The 4 explantations during the trial all occured during its 1st 3rd, according to Burke, and all 214 patients implanted with the device after that still have the devices 321 days into the study.

Burke said 1 advantage of the device is that it bypasses the need for fluoroscopy during lead implantation, because natural anatomical "landmarks" can be used to guide the procedure, rather than X-ray imaging.

"I walked into the operating room without lead on and I felt a little naked," he said.

A disadvantage of the S-ICD is that it doesn’t proved any pacing therapy, but Burke indicated that pacing could be developed for the device down the road.

"It’s a platform to start to move forward toward pacing," Burke said, noting that only 1 patient was removed from the study because they needed pacing therapy. "This is not a niche device. We implanted in anyone who presented and met the guidelines."