Single-chamber Versus Dual-chamber Implantable Cardioverter Defibrillators: Do We Need Physiologic Pacing in The Course?

Background: Many patients with ICD receive different antiarrhythmic drugs (e.g. sotalol, amiodarone, β-blockers) because of ventricular or atrial tachycardias. These drugs can cause AV-block or chronotropic incompetence resulting in a higher percentage of ventricular pacing. Methods: We analyzed in a retrospective study the impact of DDD(R) versus VVI(R) mode on subjective (NYHA classification) and objective parameters [brain natriuretic peptide (BNP), 6 minute walk test, echocardiography] in 12 of 120 patients (age 60.2 ± 11.2 years; 10 males, 2 females) who needed an upgrading of a single to a dual chamber ICD. The ICD had to be upgraded because of chronotropic incompetence in all patients with signs of progressing heart failure. Data were collected in VVI(R)-pacing and after 6 and 12 months in DDD(R)-pacing with a long AV-interval and AV hysteresis to reduce ventricular pacing. Results: The 6 minute walk test (392.4 ± 91.4 vs. 324.6 ± 93.3 m, P < 0.001), NYHA-classification (1.4 ± 0.3 vs. 2.6 ± 0.8, P < 0.0001), BNP (234.1 ± 73.5 vs. 410.4 ± 297.0 pg/ml, P < 0.001), left ventricular ejection fraction (49.8 ± 9.6 vs. 36.5 ± 10.9 %, P < 0.0001) and A-wave (73.6 ± 13.7 vs. 41.0 ± 14.0 cm/sec, P < 0.0001) improved with DDD(R)-pacing after 12 months. The ventricular pacing decreased (84.2 ± 18.1 vs. 1.1 ± 1.7 %, P < 0.0001) after 12 months by DDD(R)-pacing with long AV-interval (220.0 ± 10.4 ms) and AV hysteresis. Conclusion: Our data show a superiority of DDD(R) mode versus VVI(R) mode regarding subjective and objective parameters as NYHA-classification, BNP, 6 minute walk test, left ventricular ejection fraction and left ventricular endsystolic volume after 12 months. The improvements seem to depend on the reduction of ventricular pacing with advanced atrial contraction. But only a small number of patients needed the upgradation

The prediction of ICD therapy in multicenter automatic defibrillator implantation trial (MADIT) II like patients: a retrospective analysis

Objectives MADIT II like patients have not been compared to patients without an electrophysiological study, patients in whom ventricular tachycardia or fibrillation were induced in an electrophysiological study (EPS) and patients without an inducibility in EPS in one study. Background The multicenter automatic defibrillator implantation trial (MADIT) II showed a benefit of ICD implantation in patients with ischemic heart disease.Methods We performed a retrospective analysis in 93 patients with an ischemic heart disease and an ejection fraction ≤30% who had an ICD implanted with a follow-up at least an 18 months. Patients were divided into 3 groups according to the primary indication for ICD implantation: without EPS (group I), patients in whom ventricular tachycardia or fibrillation were inducible in EPS (group II) or patients without an inducibility in EPS (group III). Results During the mean follow-up of 32.9 ± 16.1 months 289 appropriate ICD therapies and 10 deaths occurred. The incidence of appropriate ICD therapies did not differ significantly between the groups (group I 40%, group II 54% and group III 48% of patients). We found in group II a higher risk of appropriate ICD therapies with occurrence of a specific constellation of EPS values. These patients showed a 15-fold risk (P = 0.005) of an appropriate ICD therapy. Furthermore a brain natriuretic peptide value of 265 pg/ml also predicted an appropriate ICD therapy with a 3.5-fold risk (P = 0.017).Conclusion In the present retrospective study the results of MADIT II were affirmed in the case of incidence of ventricular arrhythmias in patients with an EF < 30% and coronary heart disease. The prediction of an appropriate ICD therapy with EPS was only achieved in patients with inducibility in the EPS

Attenuation of Post-Shock Increases in Brain Natriuretic Peptide with Post Shock Overdrive Pacing

Background: Predischarge defibrillation threshold testing is often performed a few days after ICD implantation in order to validate defibrillation thresholds obtained at the time of implant. Ventricular fibrillation is induced with such testing and causes an increase in serum Brain Natriuretic Peptide (BNP) levels. BNP is an indicator for cardiac stress. We wanted to examine the feasibility to alter the trend of BNP after predischarge testing in VVI, DDD and CRT ICD´s.Methods: We measured BNP before predischarge testing and 5, 10, 20 and 40 minutes after predischarge testing in 13 groups with each 20 patients. We evaluated patients without post shock pacing and patients with a post shock pacing frequency of 60, 70, 80, 90 and 100 bpm and a duration of 30 and 60 sec as well as a post shock pacing frequency of 80 and 90 bpm and a duration of 120 sec post shock pacing. Results: Patients without post shock pacing showed the highest BNP during the follow-up. The percentage values of BNP increased consistent significantly after 5 minutes compared with BNP before predischarge testing. The percentage values of BNP trend was significantly lower with a post shock pacing of 90 bpm and duration of 60 sec. In addition, we excluded a cardiac necrosis by predischarge testing because of similar values of myoglobin, cardiac troponin I and creatine kinase during the follow-up.Conclusions: Our results suggested that post shock pacing with 90 bpm and duration of 60 sec as the best optimized post shock pacing frequency and duration for VVI, DDD and CRT ICD´s. A reduction of cardiac stress is going to be achieved with the optimization of the post shock pacing frequency and duration

Обоснование технологии гидравлического разрыва пласта на примере Приобского нефтяного месторождения (ХМАО)

В данной работе представленны обоснования технологии гидравлического разрыва пласта в низкопродуктивных пластах Приобского месторождения. В результате было предложено проведение многостадийного ГРП с увеличением стадий до 8 и на основе углеводородного геля.This paper presents the substantiation of the technology of hydraulic fracturing in low-productive formations of the Priobskoye field. As a result, it was proposed to conduct a multi-stage hydraulic fracturing with an increase in stages up to 8 and based on a hydrocarbon gel

Effect of Induced Ventricular Fibrillation and Shock Delivery on Brain Natriuretic Peptide Measured Serially Following a Predischarge ICD Test

Objectives: Brain natriuretic peptide (BNP) was a marker for heart failure and cardiac wall tension. We analysed the trend of BNP after predischarge testing in order to get non-invasive details about the cardiac stress during predischarge testing.Methods: 4-5 days after ICD implant we measured BNP, myoglobin, cardiac troponin I and creatine kinase in 20 patients before and 1, 5, 10, 20, 40, 60, 80, 100, 120 minutes and at the next day after predischarge testing. We evaluated actual values and percentage alterations of BNP. Results: BNP significantly increased with a maximum after 5 minutes (804.0 ± 803.4 vs. 475.7 ± 629.5 pg/ml, P < 0.0001) and in terms of the percentage values (100 vs. 199.4 ± 61.4 %, P < 0.0001) compared with baseline BNP. BNP decreased after that with the last significantly increased BNP value after 20 minutes (540.2 ± 604.9 vs. 475.7 ± 629.5 pg/ml, P = 0.017). We excluded a cardiac necrosis during predischarge testing because of similar values of myoglobin, cardiac troponin I and creatine kinase during the 2-hour follow-up. Conclusions: Our data showed a great increase with a doubling of BNP after 5 minutes as a result of induced ventricular fibrillation during predischarge test. This increase was not generated by myocardial necrosis but rather caused by an acute cardiac failure as a consequence of induced ventricular fibrillation in predischarge testing