No abstract

F irst introduced to clinical practice in 1980,1 the implantable cardioverter-defibrillator (ICD) improves survival in patients at high risk for sudden cardiac death. [2][3][4][5] Randomized, multicenter studies have shown a relative risk reduction in total mortality of up to 54% and an arrhythmic mortality reduction of 50% to 70%. Offsetting this mortality benefit, however, are significant acute and chronic morbidities associated with the use of transvenous leads.6-9 Procedure-related transvenous lead complications include major events such as lead dislodgement, pneumothorax, cardiac perforation, pericardial effusion, and cardiac tamponade. Chronic transvenous lead complications include systemic infections as well as insulation breaches and conductor coil breaks, which can cause inappropriate shocks and physical trauma to the heart and may render ICD therapy unavailable. The lead is the most common failure mechanism for a transvenous ICD system, and patients often outlive the useful life of the lead. 9-11 Editorial see p 938 Clinical Perspective on p 953The long-term complications associated with the transvenous ICD leads have been a rationale to develop a totally subcutaneous ICD (S-ICD). The S-ICD System (Cameron Health/Boston Scientific) senses, detects, and treats malignant ventricular tachycardia (VT)/ventricular fibrillation (VF) but leaves the heart and vasculature untouched. The subcutaneous pulse generator and electrode are placed extrathoracically, and no part of the system is exposed to most of the risks associated Background-The most frequent complications associated with implantable cardioverter-defibrillators (ICDs) involve the transvenous leads. A subcutaneous implantable cardioverter-defibrillator (S-ICD) has been developed as an alternative system. This study evaluated the safety and effectiveness of the S-ICD System (Cameron Health/Boston Scientific) for the treatment of life-threatening ventricular arrhythmias (ventricular tachycardia/ventricular fibrillation). Methods and Results-This prospective, nonrandomized, multicenter trial included adult patients with a standard indication for an ICD, who neither required pacing nor had documented pace-terminable ventricular tachycardia. The primary safety end point was the 180-day S-ICD System complication-free rate compared with a prespecified performance goal of 79%. The primary effectiveness end point was the induced ventricular fibrillation conversion rate compared with a prespecified performance goal of 88%, with success defined as 2 consecutive ventricular fibrillation conversions of 4 attempts. Detection and conversion of spontaneous episodes were also evaluated. Device implantation was attempted in 321 of 330 enrolled patients, and 314 patients underwent successful implantation. The cohort was followed for a mean duration of 11 months. The study population was 74% male with a mean age of 52±16 years and mean left ventricular ejection fraction of 36±16%. A previous transvenous ICD had been implanted in 13%. Both primary end points were met: Th...

Background-A recent landmark report has demonstrated that plasma B-type natriuretic peptide (BNP) measured in acute coronary syndromes independently predicts mortality, heart failure, and new myocardial infarction. After acute cardiac injury, left ventricular ejection fraction (LVEF) is also of prognostic significance and plays a major role in determining the therapeutic response. Methods and Results-The present report is the first from a substantial (nϭ666) cohort of patients with acute myocardial infarction to test the prognostic utility of concurrent measurements of BNP, amino-terminal BNP (N-BNP), norepinephrine, and radionuclide LVEF. The B-type peptides and LVEF were predictors of death, heart failure, and new myocardial infarction (all PϽ0.001) independent of patient age, gender, previous myocardial infarction, antecedent hypertension or diabetes, previous heart failure, plasma norepinephrine, creatinine, cholesterol, drug therapy, and coronary revascularization procedures. The combination of N-BNP (or BNP) with LVEF substantially improved risk stratification beyond that provided by either alone. Elevated N-BNP (or BNP) predicted new myocardial infarction only in patients with LVEF Ͻ40%. LVEF Ͻ40% coupled to N-BNP over the group median conferred substantial 3-year risks of death, heart failure, and new myocardial infarction of 37%, 18%, and 26%, respectively. N-BNP and BNP were equivalent prognostic markers for these clinical outcomes.

ClinicalTrials.gov number NCT00461734.

Background-Previous studies suggest that management of ambulatory hemodynamics may improve outcomes in chronic heart failure. We conducted a prospective, observational, first-in-human study of a physician-directed patient self-management system targeting left atrial pressure. Methods and Results-Forty patients with reduced or preserved left ventricular ejection fraction and a history of New York Heart Association class III or IV heart failure and acute decompensation were implanted with an investigational left atrial pressure monitor, and readings were acquired twice daily. For the first 3 months, patients and clinicians were blinded as to these readings, and treatment continued per usual clinical assessment. Thereafter, left atrial pressure and individualized therapy instructions guided by these pressures were disclosed to the patient. Event-free survival was determined over a median follow-up of 25 months (range 3 to 38 months). Survival without decompensation was 61% at 3 years, and events tended to be less frequent after the first 3 months (hazard ratio 0.16 [95% confidence interval 0.04 to 0.68], Pϭ0.012). Mean daily left atrial pressure fell from 17.6 mm Hg (95% confidence interval 15.8 to 19.4 mm Hg) in the first 3 months to 14.8 mm Hg (95% confidence interval 13.0 to 16.6 mm Hg; Pϭ0.003) during pressure-guided therapy. The frequency of elevated readings (Ͼ25 mm Hg) was reduced by 67% (PϽ0.001). There were improvements in New York Heart Association class (Ϫ0.7Ϯ0.8, PϽ0.001) and left ventricular ejection fraction (7Ϯ10%, PϽ0.001). Doses of angiotensin-converting enzyme/angiotensin-receptor blockers and ␤-blockers were uptitrated by 37% (PϽ0.001) and 40% (PϽ0.001), respectively, whereas doses of loop diuretics fell by 27% (Pϭ0.15). Conclusions-Physician-directed patient self-management of left atrial pressure has the potential to improve hemodynamics, symptoms, and outcomes in advanced heart failure. Clinical Trial Registration Information-URL: http://www.clinicaltrials.gov. Unique identifier: NCT00547729.