Risk of Sprint Fidelis defibrillator lead failure is highly dependent on age.

BACKGROUND: In 2007, Medtronic Sprint Fidelis defibrillator leads were taken off the market due to a high rate of lead failure. Current data do not allow for risk stratification of patients with regard to lead failure. AIMS: We sought to determine predictors of Sprint Fidelis lead failure. METHODS: Between 2004 and 2007, 269 Sprint Fidelis leads were implanted in 258 patients in our centre. Variables associated with lead failure were assessed by the Kaplan-Meier method and a Cox survival model. RESULTS: During a median follow-up of 2.80 years (maximum 5.32), we observed 33 (12.3%) Sprint Fidelis lead failures (5-year survival, 65.6% ± 7.5%). In univariate analysis, age was the only predictor of lead failure (hazard ratio [HR] for 1-year increase 0.97; 95% confidence interval [CI] 0.95-0.99; p=0.009). Patients aged<62.5 years (median) had a significantly increased risk of lead failure compared with patients aged>62.5 years (HR 2.80; CI 1.30-6.02; p=0.009). Survival without Sprint Fidelis lead failure was 55.6% ± 10.4%) in patients aged<62.5 years (24/134 leads) vs 78.6% ± 8.8% in patients aged>62.5 years (9/135 leads). The annual incidence of lead failure in patients aged<62.5 years was 11.6% ± 4.9% during the fourth year after implantation and 22.9% ± 13.2% during the fifth year. CONCLUSION: Overall, we found a higher rate of Sprint Fidelis lead dysfunction than previously described. Lead failure was much more frequent in younger patients. Our results emphasize the need for close follow-up of younger patients with Sprint Fidelis leads and suggest that, in these patients, the implantation of a new implantable cardioverter defibrillator lead at the time of generator replacement might be reasonable.

Prognosis and guideline-adherent antithrombotic treatment in patients with atrial fibrillation and atrial flutter: implications of undertreatment and overtreatment in real-life clinical practice; the Loire Valley Atrial Fibrillation Project.

BACKGROUND: In patients with atrial fibrillation (AF), adherence to guidelines for antithrombotic treatment is poorly followed, and undertreatment (or nonadherence with guidelines) is associated with a worse prognosis. The study objective was to evaluate whether this was also the case in a large contemporary series of unselected patients with AF in real-world clinical practice. METHODS: All patients with AF or atrial flutter seen in our institution between 2000 and 2007 were identified in a database and followed up for mortality and stroke. Antithrombotic guideline adherence was assessed according to the 2006 American College of Cardiology/American Heart Association/European Society of Cardiology guidelines. RESULTS: We reviewed outcomes in 3,646 consecutive patients with AF or atrial flutter (aged 71 ± 14 years; mean CHADS(2) [congestive heart failure, hypertension, aged ≥ 75 years, diabetes mellitus, prior stroke or transient ischemic attack] score, 1.5 ± 1.1). Antithrombotic treatment was in agreement with the guidelines in 53% of patients, whereas 31% were classified as undertreated and 16% as overtreated. Among other parameters, nonpermanent AF and atrial flutter were independently associated with an increased risk of undertreatment. After a follow-up of 953 ± 767 days (median, 771 days; interquartile range, 1,286 days), guideline adherence was associated with a lower risk of adverse events (death from all causes or stroke) compared with undertreatment (relative risk, 0.47; 95% CI, 0.40-0.55; P < .0001). Overtreatment was associated with a lower risk of adverse events compared with the guideline-adherent population (relative risk, 0.40; 95% CI, 0.28-0.58; P < .0001). Factors independently associated with increased risk of mortality or stroke were antithrombotic undertreatment, older age, heart failure, renal failure, diabetes, male sex, and previous history of stroke. CONCLUSIONS: Guideline nonadherence and undertreatment with antithrombotic agents in unselected real-world patients with AF or atrial flutter are independently associated with a high risk of stroke and mortality.

Quantification of ventricular resynchronization reserve by radionuclide phase analysis in heart failure patients: a prospective long-term study.

BACKGROUND: Phase analysis, developed to assess dyssynchrony from ECG-gated radionuclide ventriculography, has shown promising results. We hypothesized that quantifying the cardiac resynchronization reserve, that is, the extent of response to cardiac resynchronization therapy (CRT), by radionuclide imaging could potentially identify patients who are best suited for CRT. METHODS AND RESULTS: Seventy-four patients ages 64.8±10.1 years were prospectively studied from July 2004 to July 2006, of whom 62.2% and 37.8%, respectively, were in New York Heart Association class 3 and 4. Mean QRS width was 173±25 ms. ECG-gated radionuclide ventriculography to quantify interventricular and intraventricular dyssynchrony was performed at baseline with and without CRT and at the 3-month follow-up visit. Amino-terminal-pro-brain natriuretic peptide (NT-pro-BNP) levels were also determined at baseline and at 3 months. During a mean follow-up of 10.1±7.6 months, there were 37 (50%) clinical events that defined the nonresponder group, including cardiac death or readmission for worsening heart failure. In multivariate Cox model analysis, higher NT-pro-BNP blood levels were associated with a significant increase in the risk for event (hazard ratio=1.085 for a 100 pg/L increase in NT-pro-BNP; 95% confidence interval, 1.014 to 1.161). Each 10° elevation in intraventricular dyssynchrony was associated with a decrease in the risk of events (hazard ratio=0.456, 95% confidence interval, 0.304 to 0.683). Receiver operating characteristic curve analysis demonstrated that an interventricular dyssynchrony cutoff value of 25.5° for intraventricular synchrony yielded 91.4% sensitivity and 84.4% specificity for predicting a good response to CRT. CONCLUSIONS: The quantification of interventricular dyssynchrony with radionuclide phase analysis suggests that early postimplantation interventricular dyssynchrony may provide identification of CRT responders.

Antithrombotic treatment and the risk of death and stroke in patients with atrial fibrillation and a CHADS2 score=1.

In patients with atrial fibrillation (AF) and an intermediate risk of stroke (CHADS2 score =1), available evidence from clinical trials is inconclusive and the present guidelines for the management of AF indicate that the choice between oral anticoagulant and aspirin in these patients is open. Our goal was to evaluate whether, in patients with AF and only one moderate risk factor for thromboembolism, treatment with an oral anticoagulant is appreciably more beneficial than treatment with an antiplatelet agent. Among 6,517 unselected patients with AF, 1,012 of them (15.5%) had a CHADS2 score of 1 and were liable to treatment with an antiplatelet agent or an anticoagulant. An oral anticoagulant was prescribed for 606 patients (59.9%) and an antiplatelet agent or no antithrombotic treatment for 406 (40.1%). During follow-up (median=793 days, interquartile range=1,332 days), 105 deaths (10.4%) and 19 strokes (1.9%) were recorded. The administration of an anticoagulant was associated with a lower rate of events (relative risk=0.42, 95% confidence interval 0.29-0.60, p<0.0001) than when no anticoagulant was prescribed. Results remained similar after adjustment for age and other confounding factors. In contrast, prescription of an antiplatelet agent was not associated with a lower risk of events. Factors independently associated with an increased risk of events were older age (p<0.0001), concomitant heart failure (p=0.0002), diabetes (p=0.0025), lack of prescription of an anticoagulant (p<0.0001) and permanent AF (p=0.04). Thus, prescription of an anticoagulant is independently associated with a decreased risk of death or stroke among patients with AF and a CHADS2 score =1.

Comparison of beta blocker and digoxin alone and in combination for management of patients with atrial fibrillation and heart failure.

In patients with atrial fibrillation (AF) and heart failure (HF), beta blockers and digoxin reduce the ventricular rate, but controversy exists concerning how these drugs affect prognosis in this setting. This study compared the effects of beta blocker and digoxin on mortality in patients with both AF and HF. In a single-center institution, patients with AF and HF seen between January 2000 and January 2004 were identified and followed until September 2007. Of 1,269 consecutive patients with both AF and HF, 260 were treated with a beta blocker alone, 189 with beta blocker plus digoxin, 402 with digoxin alone, and 418 without beta blocker or digoxin (control group). During a follow-up of 881+/-859 days, 247 patients died. Compared with the control group, treatment with beta blocker was associated with a decreased mortality (relative risk=0.58, 95% confidence interval 0.40 to 0.85, p=0.005 for beta blocker alone and 0.59, 95% confidence interval 0.40 to 0.87, p=0.008 for beta blocker plus digoxin). By contrast, treatment with digoxin alone was not associated with a better survival (relative risk=0.97, 95% confidence interval 0.73 to 1.30, p=NS). Results remained significant after adjustment for potential confounders and similar when we considered, separately, HF with permanent or nonpermanent AF, presence or absence of coronary disease, and patients with decreased or preserved systolic function. In conclusion, in unselected patients with AF and HF, treatments with beta blocker alone or with beta blocker plus digoxin are associated with a similar decrease in the risk of death. Digoxin alone is associated with a worse survival chance, similar to that of patients without any rate control treatment.