Обзор американских кардиологических журналов за неделю (ссылки)

[Chevychelov]

CRT found superior to right ventricular apical pacing in patients with permanent AF

Heart Rhythm Society 32nd Annual Scientific Sessions

SAN FRANCISCO – Patients with permanent atrial fibrillation who, on top of atrioventricular junction ablation, were treated with cardiac resynchronization therapy had lower rates of worsening HF and hospitalizations for HF compared with those treated with right ventricular apical pacing, according to new data presented at the Heart Rhythm Society’s 32nd Annual Scientific Sessions.

According to Michele Brignole, MD, the study’s primary investigator andhead of the department of cardiology, Ospedali del Tigullio, Lavagna, Italy, the prospective study began as an attempt to add to the current level of understanding of right ventricular apical pacing vs. cardiac resynchronization therapy (CRT) in patients with AF, which he said only consisted of a few small short-term trials.

“So there is a lack of knowledge,” Brignole told Cardiology Today. “For this reason, current guidelines in America (2008) and Europe (2010) on CRT have ranked CRT pacing as Class IIa level of evidence B and only for a subgroup of patients with AF, specifically the subgroup of patients with large QRS, low ejection fraction and NYHA Class 3 or 4.”

To bring further clarification to this issue on a larger scale, Brignole and fellow researchers randomly assigned 186 patients from 19 hospitals to receive either optimized echo-guided CRT (n=97) or right ventricular apical pacing (n=89). All patients had previous atrioventricular junction and CRT implantation performed successfully. The study’s primary endpoint was a composite of death from HF, hospitalization due to HF or worsening HF.

During a median follow-up of 20 months, the primary endpoint proved to be significantly lower in the CRT group vs. those in the right ventricular group (11% vs. 26%; sub-HR=0.37; 95% CI, 0.18-0.73). This was due primarily to significantly lower rates of worsening HF (sub-HR=0.27; 95% CI, 0.12-0.58) and hospitalizations for HF (sub-HR=0.20; 95% CI, 0.06-0.72) in the CRT group because the rates of mortality between groups were similar. As a result, the CRT mode was an independent predictor of the absence of clinical failure (OR=0.19; 95% CI, 0.05-0.67).

For Brignole, two important implications can be taken from this trial. “The first is that this trial confirms the Class IIa indication of the most recent guidelines,” he said. “This indication was mainly based on an expert consensus opinion, rather than based on real studies. This is the first study that gives evidence of clinical benefit of therapy in patients who already have a IIa indication. In other words, this study could serve to upgrade the current recommendation from IIA to Class I.”

The second implication, however, according to Brignole, is even more important. “This study, if confirmed by others, would expand the indication of guidelines to all patients with severe symptomatic AF, independently for ejection fraction, length and duration of QRS and so on,” he said, but adding that this study must be regarded as somewhat preliminary. – by Brian Ellis
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Infection incidence for pacemaker implants increased from 1993 to 2008

Heart Rhythm Society 32nd Annual Scientific Sessions

SAN FRANCISCO — The burden of infection among recipients of cardiac implantable electronic devices has increased between 1993 and 2008 for pacemakers, but not for implantable cardioverter defibrillators, according to new research.

Researchers for the study reviewed data from the National Inpatient Sample to identify patients receiving pacemakers and ICD between 1993 and 2008. They used ICD-9-CM procedure codes to identify the specific patients, including the codes for primary pacemaker, primary ICD, pacemaker removal and ICD removal. Patient comorbidities and the national incidence for pacemakers and ICDs were evaluated.

A total of 3.2 million patients received pacemakers and 1.1 million received ICDs from 1993 to 2008, and a total of 73,000 of them were diagnosed with infection (1.88% for pacemakers and 1.13% for ICDs). A 224% increase in the infection rate was reported in pacemaker patients from 1993 (1.6%) to 2008 (3.5%), while ICD infection rates remained constant over time. The incidence of infection was also 75% higher in patients with pacemakers vs. those with ICDs (P<.001). The incidence in infection rose in ICD patients with HF (OR=1.28), renal failure (OR=2.18) and respiratory failure (OR=1.30), while pacemaker infection rose in patients with diabetes (OR=1.12), HF (OR=1.46), renal failure (OR=2.38) and respiratory failure (OR=2.25).

The researchers also noted that in 2008, over 32% of patients with infected ICDs or pacemakers were diagnosed with renal failure, which was an increase from 1993.

“The dimensions of the national cardiac implantable electronic device infection burden are changing due to the increasing prevalence of comorbidities, particularly renal failure,” the researchers concluded in their abstract. “Strategies for decreasing cardiac implantable electronic device infection should include a better understanding of periprocedural risk factors.”
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Primary prevention ICD yielded higher overall mortality in women than men

Heart Rhythm Society 32nd Annual Scientific Sessions

SAN FRANCISCO — Women who received an implantable cardioverter defibrillator for primary prevention of sudden death experienced a similar arrhythmic death rate but a mortality rate nearly 10% higher than in men, according to findings presented at the Heart Rhythm Society’s 32nd Annual Scientific Sessions.

Data on the survival benefit of ICD for women with cardiomyopathy to prevent sudden death are unclear. The current retrospective analysis measured the effect of gender on the appropriate use of ICD therapy and associated mortality rates in 525 consecutive patients. Eligible patients had ischemic or nonischemic cardiomyopathy and had undergone ICD implantation for primary prevention of sudden death.

Overall, there were 160 deaths. The mortality rate was 38.9% among 121 women and 30% among 404 men.

Appropriate ICD therapies were administered to 14.9% of women and 17.1% of men. Four-year survival rates were different between the groups (P=.039), but there was no difference in the rate of appropriate ICD therapy, according to results of a Kaplan-Meier analysis.

Mortality was the primary endpoint, along with appropriate ICD therapy at the 4-year mark. The mean duration of follow-up was 3.8 years.

The researchers assessed demographic information and data for comorbid illnesses and medications for all patients. The 121 women in the study accounted for 23.1% of the population and had similar baseline characteristics as men. Women were aged 61 years and men were aged 62.5 years. Women also had similar ejection fraction (25%) and comorbidities and medication use as men.

Regarding baseline characteristics that were not similar, 81% of men were white vs. 63% of women (P<.001). The tobacco use rate was 63% among men and 43% among women (P<.001). Fifty percent of men had undergone prior coronary bypass surgery vs. 26% of the women (P<.001).

“Women who received an ICD for prevention of [sudden death] had a similar arrhythmic event rate as men,” the researchers wrote. “However, the impact of primary prevention ICD therapy is attenuated by increased mortality rate in female patients.”
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SCD-HeFT: Frequency of non-sustained ventricular tachycardia associated with mortality

Heart Rhythm Society 32nd Annual Scientific Sessions

SAN FRANCISCO — The number of non-sustained ventricular tachycardia episodes that patients with HF experience is linked with mortality, results from a study presented at the Heart Rhythm Society’s 32nd Annual Scientific Sessions indicated.

Researchers for the Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT) enrolled 2,521 patients with NYHA Class II or III HF and with an ejection fraction of at least 35%, of whom 2,040 had readable 24-hour Holter monitoring data. Holter monitoring data were obtained 2 weeks before randomization to placebo, amiodarone or an implantable cardioverter defibrillator. The researchers evaluated the Holter data and characterized non-sustained (≥3 beats in <30 seconds) ventricular tachycardia (NSVT), identifying it as at least 120 beats/minute. Holter staff and physician readers were blinded to clinical parameters, randomization and status outcomes. Cox regression models were used to identify prognostic baseline covariates such as age, ejection fraction and NYHA Class.

According to the researchers, no NSVT was observed in 1,367 (67%) patients on baseline monitoring; at least one 1 episode was seen in 673 (33%) patients; at least two episodes were seen in 402 (20%) patients; and at least three episodes in 291 patients (14%). The mean NSVT rate was 155 beats/minute, with a mean duration of 4.5 beats. They determined that at least two NSVT episodes were predictive of overall mortality.

“The presence of only one episode of NSTV on the baseline Holter monitoring did not confer an increase in overall mortality, whereas >2 NSVT episodes did confer increased overall mortality compared to less frequent NSVT episodes,” the researchers concluded in an abstract.