P3523Cardiac contractility modulation provides improved ventilatory efficiency and reduces oscillatory breathing pattern

Introduction

Cardiac Contractility Modulation (CCM) is a treatment for patients with heart failure with reduced ejection fraction (HFrEF) providing improved myocardial molecular and biochemical characteristics and thus improved exercise tolerance and quality of life by application of electrical signals during the absolute refractory period.

Cardiopulmonary exercise testing is an integrative method to assess exercise tolerance in heart failure patients providing insights in circulatory, respiratory and metabolic reactions during exercise. The VE/VCO2-Slope (minute ventilation/carbon dioxide production) and an oscillatory breathing pattern have widely been demonstrated to have strong prognostic value for patients with chronic heart failure.

Methods

Between February 2017 and January 2019 15 patients (mean age 64.4±7.9 years, NYHA 2.93±0.58) with standard indication for CCM-therapy have been enrolled in a single center in Germany. Prior to implantation of the Optimizer Smart System, symptom-limited cardiopulmonary exercise testing was performed using a bicycle ramp protocol (25W+10W/min). The Follow-up was conducted 6 weeks post implantation.

The control group consisted of 45 patients (mean age 64.8±7.9 years, NYHA 2.2±0.72) with stable systolic heart failure and reduced ejection fraction. Statistical Analysis was performed by paired and unpaired t tests.

Results

6 weeks after CCM-implantation the VE/VCO2-Slope showed a significant decrease (39.6±11.1 vs. 36.6±8.9, p<0.05) showing changes in ventilatory efficiency whereas the control-group showed stable measurements with even an increasing tendency (33.6±7.4 vs. 34.2±7.4, p=0.43). The absolute change of the VE/VCO2-Slope between the CCM-group and control-group highlights the improvement after the intervention (−2.99±5.07 vs. 0.63±4.79, p<0.05). The number of patients presenting an oscillatory breathing pattern markedly decreased with CCM-therapy (11 of 15 vs. 6 of 15, p<0.05), whereas even one additional patient of the control group showed an oscillatory breathing pattern at follow up (15 of 45 vs. 16 of 45).

In contrast, subjects showed no significant changes in watt-measurements (72.67 W ± 19.2 W vs. 76.57 W ± 18.5 W) or maximal oxygen uptake (1034 ml/min ± 247 ml/min vs. 1104 ml/min ± 256 ml/min) compared to baseline. Similarly, the control-group showed stable measurements for external load (79.9 W ± 16.4 W vs. 77.1 W ± 17.5 W) and peak oxygen uptake (1097 ml/min ± 225 ml/min vs. 1116 ml/min ± 330 ml/min).

Conclusion

Cardiac Contractility Modulation provides improved ventilatory efficiency measures by VE/VCO2-slope and reduces oscillatory breathing pattern during exercise at follow up. As the low ventilatory efficiency observed in patients with heart failure constitutes an important predictor of cardiovascular mortality these results provide an interesting insight of therapeutic effects of Cardiac Contractility Modulation apart from VO2-measurements.

European survey on efficacy and safety of duty-cycled radiofrequency ablation for atrial fibrillation

AIMS

Duty-cycled radiofrequency ablation (RFA) has been used for atrial fibrillation (AF) for around 5 years, but large-scale data are scarce. The purpose of this survey was to report the outcome of the technique.

METHODS AND RESULTS

A survey was conducted among 20 centres from seven European countries including 2748 patients (2128 with paroxysmal and 620 with persistent AF). In paroxysmal AF an overall success rate of 82% [median 80%, interquartile range (IQR) 74-90%], a first procedure success rate of 72% [median 74% (IQR 59-83%)], and a success of antiarrhythmic medication of 59% [median 60% (IQR 39-72%)] was reported. In persistent AF, success rates were significantly lower with 70% [median 74% (IQR 60-92%)]; P = 0.05) as well as the first procedure success rate of 58% [median 55% (IQR 47-81%)]; P = 0.001). The overall success rate was similar among higher and lower volume centres and were not dependent on the duration of experience with duty-cycled RFA (r = -0.08, P = 0.72). Complications were observed in 108 (3.9%) patients, including 31 (1.1%) with symptomatic transient ischaemic attack or stroke, which had the same incidence in paroxysmal and persistent AF (1.1 vs. 1.1%) and was unrelated to the case load (r = 0.24, P = 0.15), bridging anticoagulation to low molecular heparin, routine administration of heparin over the long sheath, whether a transoesophageal echocardiogram was performed in every patient or not and average procedure times.

CONCLUSION

Duty-cycled RFA has a self-reported success and complication rate similar to conventional RFA. After technical modifications a prospective registry with controlled data monitoring should be conducted to assess outcome.