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EP Europace, 2009
Methods and results We evaluated the performance of the Wavelet TM morphology discrimination algo... more Methods and results We evaluated the performance of the Wavelet TM morphology discrimination algorithm (Medtronic, Inc.) independently from other discrimination enhancements (rate onset and interval stability). A non-randomized, prospective, multicenter, and observational study was designed to determine the sensitivity and specificity of the new morphology criterion. Sensitivity and specificity in slow tachycardia with cycle length (CL) between 340 and 500 ms were analysed as a pre-specified secondary endpoint. A total of 771 spontaneous episodes in 106 patients were analysed. Five hundred and twenty-two episodes corresponded to true supraventricular tachycardia (SVT) with ventricular CL in the VT or FVT zone, of which 473 had therapy appropriately withheld. Of the 249 episodes of true VT/FVT, 21 were classified according to the Wavelet TM criteria as SVT (specificity: 90.6%; sensitivity: 91.6%). All of them were spontaneously terminated with no adverse clinical consequences. No syncopal episodes occurred. For VTs in the slowest analysed range (CL: 340-500 ms), a total of 235 episodes were studied, yielding a specificity of 95.9% and sensitivity of 83.2%. Conclusion Wavelet TM discrimination criteria in single-chamber ICDs as the sole discriminator can significantly reduce inappropriate therapy for SVT, not only in the range of VTs in the slowest analysed range (340-500 ms for this study) but also for faster VTs. No significant clinical consequences were found when the algorithm was used, but final data should prompt the use of the algorithm in combination with a high rate time-out feature.
European Heart Journal, 1990
Electrophysiological properties were studied in a heterotopic heart transplant model developed in... more Electrophysiological properties were studied in a heterotopic heart transplant model developed in 44 dogs (Group I). Cycle length was 359-5 ± 55-2 ms in the recipient heart and 500-9 ± 77-9 ms in the donor heart (P<0001). Sinoatrialconduction time was 38-6± 13-6ms in the recipient heart and38-6±10-4ms in that of the donor (not significant). The Wenckebach point was 175-4±31-1 ms in the recipient organ and 214-3 ± 42-6 ms in the donor heart (P < 0-001). The retrograde block point was 271-6 ± 48-0 ms in the recipient heart and 353-6±47-3 ms in that of the donor (P<0-01). The effective antegrade refractory period was 133-4 ±28-7 ms in the recipient heart and 167-3 ±46-3 ms in the donor organ (P< 0-001). An epicardial atrial cartography was performed at 44 preset points in both hearts, revealing a normal activation sequence and delays of 36-98 ms (mean 58 ms) in the recipient heart and from 39 to 59 ms (mean 50 ms) in the donor heart (not significant). In another 11 dogs (Group II), the same electrophysiological study was carried out under basal conditions and after pharmacological blockade of the autonomic nervous system with atropine (004 mg (kg body weight) ~') and propranolol (0-2 mg (kg body weight) ~'). No significant differences were found in any of the parameters studied upon comparison of Group II animals in basal conditions with Group I recipients, and Group II dogs after blockade with Group I donors. These results demonstrate that the differences in automatism, conduction and refractoriness between the donor and recipient hearts are not attributable to differences in the haemodynamic situation or in the anaesthetic technique, but to denervation.
Europace, 2007
Aims Right ventricular (RV) pacing has been shown to cause heart failure symptoms in patients wit... more Aims Right ventricular (RV) pacing has been shown to cause heart failure symptoms in patients with and without previous systolic left ventricular (LV) dysfunction. The aim here was to evaluate the preventive effect of biventricular pacing vs. RV apical pacing in patients with indication for permanent ventricular pacing. Methods PREVENT-HF is an ongoing multicentre randomized controlled pilot study designed to assess whether biventricular pacing is superior to RV pacing in patients receiving a bradycardia pacemaker for standard indications. Patients with Class I or IIa indication according to ACC/AHA guidelines for cardiac pacing judged likely to require high (580%) ventricular pacing are randomized to receive either RV or biventricular stimulation. Patients are ineligible if younger than 18 years, have Class III or IV heart failure, or experienced a recent myocardial infarction or cardiac surgery. Echocardiographic parameters of LV function are assessed at baseline, 6 months, and 12 months. The primary endpoint is change in LV end diastolic volume. Secondary outcomes include LV ejection fraction, mortality, morbidity, and mitral regurgitation. In subsets of patients, NT-pro-BNP and oxygen uptake are analysed. Centres in Spain (five), Italy (four), and Germany (seven) will enrol 100 patients. Conclusion PREVENT-HF will contribute to better define the role of chronic biventricular pacing for advanced atrioventricular block.
EP Europace, 2009
Methods and results We evaluated the performance of the Wavelet TM morphology discrimination algo... more Methods and results We evaluated the performance of the Wavelet TM morphology discrimination algorithm (Medtronic, Inc.) independently from other discrimination enhancements (rate onset and interval stability). A non-randomized, prospective, multicenter, and observational study was designed to determine the sensitivity and specificity of the new morphology criterion. Sensitivity and specificity in slow tachycardia with cycle length (CL) between 340 and 500 ms were analysed as a pre-specified secondary endpoint. A total of 771 spontaneous episodes in 106 patients were analysed. Five hundred and twenty-two episodes corresponded to true supraventricular tachycardia (SVT) with ventricular CL in the VT or FVT zone, of which 473 had therapy appropriately withheld. Of the 249 episodes of true VT/FVT, 21 were classified according to the Wavelet TM criteria as SVT (specificity: 90.6%; sensitivity: 91.6%). All of them were spontaneously terminated with no adverse clinical consequences. No syncopal episodes occurred. For VTs in the slowest analysed range (CL: 340-500 ms), a total of 235 episodes were studied, yielding a specificity of 95.9% and sensitivity of 83.2%. Conclusion Wavelet TM discrimination criteria in single-chamber ICDs as the sole discriminator can significantly reduce inappropriate therapy for SVT, not only in the range of VTs in the slowest analysed range (340-500 ms for this study) but also for faster VTs. No significant clinical consequences were found when the algorithm was used, but final data should prompt the use of the algorithm in combination with a high rate time-out feature.
European Heart Journal, 1990
Electrophysiological properties were studied in a heterotopic heart transplant model developed in... more Electrophysiological properties were studied in a heterotopic heart transplant model developed in 44 dogs (Group I). Cycle length was 359-5 ± 55-2 ms in the recipient heart and 500-9 ± 77-9 ms in the donor heart (P<0001). Sinoatrialconduction time was 38-6± 13-6ms in the recipient heart and38-6±10-4ms in that of the donor (not significant). The Wenckebach point was 175-4±31-1 ms in the recipient organ and 214-3 ± 42-6 ms in the donor heart (P < 0-001). The retrograde block point was 271-6 ± 48-0 ms in the recipient heart and 353-6±47-3 ms in that of the donor (P<0-01). The effective antegrade refractory period was 133-4 ±28-7 ms in the recipient heart and 167-3 ±46-3 ms in the donor organ (P< 0-001). An epicardial atrial cartography was performed at 44 preset points in both hearts, revealing a normal activation sequence and delays of 36-98 ms (mean 58 ms) in the recipient heart and from 39 to 59 ms (mean 50 ms) in the donor heart (not significant). In another 11 dogs (Group II), the same electrophysiological study was carried out under basal conditions and after pharmacological blockade of the autonomic nervous system with atropine (004 mg (kg body weight) ~') and propranolol (0-2 mg (kg body weight) ~'). No significant differences were found in any of the parameters studied upon comparison of Group II animals in basal conditions with Group I recipients, and Group II dogs after blockade with Group I donors. These results demonstrate that the differences in automatism, conduction and refractoriness between the donor and recipient hearts are not attributable to differences in the haemodynamic situation or in the anaesthetic technique, but to denervation.
Europace, 2007
Aims Right ventricular (RV) pacing has been shown to cause heart failure symptoms in patients wit... more Aims Right ventricular (RV) pacing has been shown to cause heart failure symptoms in patients with and without previous systolic left ventricular (LV) dysfunction. The aim here was to evaluate the preventive effect of biventricular pacing vs. RV apical pacing in patients with indication for permanent ventricular pacing. Methods PREVENT-HF is an ongoing multicentre randomized controlled pilot study designed to assess whether biventricular pacing is superior to RV pacing in patients receiving a bradycardia pacemaker for standard indications. Patients with Class I or IIa indication according to ACC/AHA guidelines for cardiac pacing judged likely to require high (580%) ventricular pacing are randomized to receive either RV or biventricular stimulation. Patients are ineligible if younger than 18 years, have Class III or IV heart failure, or experienced a recent myocardial infarction or cardiac surgery. Echocardiographic parameters of LV function are assessed at baseline, 6 months, and 12 months. The primary endpoint is change in LV end diastolic volume. Secondary outcomes include LV ejection fraction, mortality, morbidity, and mitral regurgitation. In subsets of patients, NT-pro-BNP and oxygen uptake are analysed. Centres in Spain (five), Italy (four), and Germany (seven) will enrol 100 patients. Conclusion PREVENT-HF will contribute to better define the role of chronic biventricular pacing for advanced atrioventricular block.