Miniaturized implantable cardiac monitor with a long sensing vector (BIOMONITOR III): Insertion procedure assessment, sensing performance, and home monitoring transmission success.

BACKGROUND: Implantable Cardiac Monitors (ICMs) are used for long-term monitoring of arrhythmias. BIOMONITOR III is a novel ICM with a miniaturized profile, long sensing vector due to a flexible antenna, simplified implantation with a dedicated insertion tool for pocket formation and ICM placement in a single step, and daily automatic Home Monitoring (HM) function. METHODS: In 47 patients undergoing BIOMONITOR III insertion for any ICM indication, 16 investigators at 10 Australian sites assessed handling characteristics of the insertion tool, R-wave amplitudes, noise burden, P-wave visibility, and HM transmission success. Patients were followed for 1 month. RESULTS: All 47 attempted insertions were successful. Median time from skin incision to removal of the insertion tool after ICM insertion was 39 s (IQR 19-65) and to wound closure and cleaning was 4.7 min (IQR 3.5-7.8). All aspects of the insertion tool were rated as "good" or "excellent" in ≥97.9% and "fair" in ≤2.1% of patients, except for "force needed for tunnelling" (91.5% good/excellent, 8.5% fair). Based on HM data, R-waves in the first month were stable at 0.70 ± 0.37 mV. Median noise burden (disabling automatic rhythm evaluation) was 0.19% (IQR 0.00-0.93), equivalent to 2.7 min (IQR 0.0-13.4) per day. In HM-transmitted ECG strips with regular sinus rhythm, P-waves were visible in 89 ± 24% of heart cycles. Patient-individual automatic Home Monitoring transmission success was 98.0% ± 5.5%. CONCLUSIONS: The novel ICM performed well in all aspects studied, including fast insertion, reliable R-wave sensing, good P-wave visibility, and highly successful HM transmissions.

Innovative tools for atrial fibrillation ablation.

INTRODUCTION: Catheter ablation (CA) for atrial fibrillation (AF) is an effective treatment option with encouraging clinical outcome data. Further improvement of catheter technologies is desirable, in particular for patients with persistent and long-standing persistent AF. The aim of this review is to provide an overview of novel ablation tools in AF-ablation. AREAS COVERED: The most widely used ablation tool still is the single-tip catheter for radiofrequency (RF) ablation. Contact-force (CF) catheters and the introduction of individualized ablation protocols may overcome limitations of single-tip RF-based ablation. Furthermore, balloon-based pulmonary vein isolation (PVI) - first and foremost the cryoballoon (CB) - based ablation - moved into the foreground especially for the treatment of paroxysmal AF, because of its ease of use and proven safety. Upcoming RF balloon technologies are also promising. Moreover, new mapping and imaging technologies might help to identify non-PV-triggers in patients with arrhythmia recurrence and may have the potential to enable real-time therapy assessment. EXPERT OPINION: New ablation tools such as CF-sensing catheters or novel balloon-devices could help to overcome the major limitation of PV-reconnection and lead to improved outcomes. Moreover, novel mapping tools to identify extra-PV-triggers may improve ablation success in patients with persistent and long-standing persistent AF.

Left ventricular torsional dynamics post exercise for LV diastolic function assessment.

AIMS: 2D speckle tracking echocardiography allows for assessment of left ventricular (LV) torsional deformation as a composite function of the radial, longitudinal and circumferential fibres. We test the hypothesis that post-exercise LV torsional dynamics are more sensitive markers for myocardial dysfunction than resting measures, and better predictors for exercise capacity compared to post-exercise LV diastolic filling pressure (E/e'). METHODS: We studied 88 patients referred for stress echocardiogram. Treadmill exercise was performed using Bruce protocol, and echo images were acquired using GE Vivid 7. LV rotational dynamics were analysed by speckle tracking method using the GE ECHOPAC software. Tertiles were defined according to exercise capacity measured by the achieved metabolic equivalents (METS) adjusted for age and gender. Comparison was made between LV torsional dynamics and E/e' to correlate with METS to predict exercise capacity. RESULTS: Mean age of the study population was 58 years, 48% females. Patients with systolic dysfunction or evidence of ischaemia were excluded from the analysis. No significant correlation was found between METS and LV torsion measures at rest. There was statistically significant correlation between METS and post-exercise LV torsion (r=0.34, p=0.001), twist velocity increase (r=0.27, p=0.01), and incremental change in torsion (r=0.22, p<0.05). In addition, a correlation was also shown between post-exercise E/e' and METS (r=-0.33, p=0.002). CONCLUSION: Post-exercise LV torsional dynamics correlate with exercise capacity and may be a useful tool for assessing LV myocardial function in subjects with normal LVEF.