Chronotropic incompetence in Chagas disease: usefulness of dual sensor pacemaker based on volume minute and accelerometer

Subcutaneous Implantable Cardioverter Defibrillator: Early Experience

Introduction

The implantable cardioverter defibrillator had been increasing the survival of patients at high risk for sudden cardiac death. The subcutaneous implantable cardioverter defibrillator was developed to mitigate the complications inherent to lead placement into cardiovascular system.

Objective

To report the initial experience of 18 consecutive cases of subcutaneous implantable cardioverter defibrillator implantation showing the indications, potential pitfalls and perioperative complications.

Methods

Between September 2016 and March 2017, 18 patients with indication for primary and secondary prevention of sudden cardiac death, with no concomitant indication for artificial cardiac pacing, were included.

Results

The implantation of the subcutaneous implantable cardioverter defibrillator successfully performed in 18 patients. It was difficult to place the subcutaneous lead at the parasternal line in two patients. One patient returned a week after the procedure complaining about an increase in pain intensity at pulse generator pocket site, which was associated with edema, temperature rising and hyperemia. Two patients took antialgic medication for five days after surgery. A reintervention was necessary in one patient to replace the lead in order to correct inappropriate shocks caused by myopotential oversensing.

Conclusion

In our initial experience, although the subcutaneous implantable cardioverter defibrillator implantation is a less-invasive, simple-accomplishment procedure, it resulted in a bloodier surgery perhaps requiring an operative care different from the conventional. Inappropriate shock by oversensing is a reality in this system, which should be overcame in order not to become a limiting issue for its indication.

Safety profile and efficacy of ivabradine in heart failure due to Chagas heart disease: a post hoc analysis of the SHIFT trial

AIMS

The SHIFT trial showed that ivabradine reduced heart rate (HR) and the risk of cardiovascular outcomes. Concerns remain over the efficacy and safety of ivabradine on heart failure (HF) due to Chagas disease (ChD). We therefore conducted a post hoc analysis of the SHIFT trial to investigate the effect of ivabradine in these patients.

METHODS AND RESULTS

SHIFT was a randomized, double-blind, placebo-controlled trial in symptomatic systolic stable HF, HR ≥ 70 b.p.m., and in sinus rhythm. The ChD HF subgroup included 38 patients, 20 on ivabradine, and 18 on placebo. The ChD HF subgroup showed high prevalence of bundle branch right block and, compared with the overall SHIFT population, lower systolic blood pressure; higher use of diuretics, cardiac glycosides, and antialdosterone agents; and lower use of angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker or target daily dose of beta-blocker. ChD HF presented a poor prognosis (all-cause mortality at 2 years was ~60%). The mean twice-daily dose of ivabradine was 6.26 ± 1.15 mg and placebo 6.43 ± 1.55 mg. Ivabradine reduced HR from 77.9 ± 3.8 to 62.3 ± 10.1 b.p.m. (P = 0.005) and improved functional class (P = 0.02). A trend towards reduction in all-cause death was observed in ivabradine arm vs. placebo (P = 0.07). Ivabradine was not associated with serious bradycardia, atrioventricular block, hypotension, or syncope.

CONCLUSIONS

ChD HF is an advanced form of HF with poor prognosis. Ivabradine was effective in reducing HR in these patients and improving functional class. Although our results are based on a very limited sample and should be interpreted with caution, they suggest that ivabradine may have a favourable benefit-risk profile in ChD HF patients.