Right ventricular pacing is an independent predictor for ventricular tachycardia/ventricular fibrillation occurrence and heart failure events in patients with an implantable cardioverter-defibrillator

Aims: There is increasing evidence that right ventricular (RV) pacingmay have detrimental effects by increasing morbidity and mortalityfor heart failure in implantable cardioverter–defibrillator(ICD) patients. In this study we prospectively tested the hypothesisthat cumulative RV pacing increases ventricular tachycardia/ventricularfibrillation (VT/VF) occurrence (primary endpoint) and hospitalizationand mortality for heart failure (secondary endpoint) in a predominantlysecondary prophylactic ICD patient population. Methods and results: Two hundred and fifty patients were divided into two groupsaccording to the median of cumulative RV pacing (2 vs. >2%)and prospectively followed-up for occurrence of primary andsecondary endpoints for 18 ± 4 months. Established predictorsfor VT/VF occurrence and heart failure events such as age, leftventricular ejection fraction (EF), QRS duration, history ofatrial fibrillation, and NT-proBNP were collected at enrolment.Multivariate Cox regression analysis revealed that cumulativeRV pacing > 2% and EF < 40% were independent predictorsfor VT/VF occurrence and heart failure events. Kaplan–Meieranalysis showed that patients with >2% cumulative RV pacingmore frequently suffered from VT/VF occurrence and heart failurehospitalization. Conclusion: Cumulative RV pacing > 2% and EF < 40% are independentpredictors for VT/VF occurrence and mortality and hospitalizationfor heart failure in predominantly secondary prophylactic ICDpatients. Our data show that algorithms capable of reducingcumulative RV pacing should be used more frequently in clinicalpractice.     

Difference in humoral biomarkers for myocardial injury and inflammation in radiofrequency ablation versus cryoablation

BACKGROUND: Markers of myocardial injury and inflammation have been shown to be elevated following radiofrequency (RF) ablation. This study aimed to compare RF ablation and cryoablation for their impact on markers for myocardial injury and inflammation. METHODS: Nineteen patients received catheter ablation for atrial flutter by either cryoablation (10 patients) or open-irrigated RF ablation (nine patients). Venous blood samples for troponin T (TnT), creatinkinase (CK), and the cardiac isoenzyme MB (CKMB) were obtained before, at six hours after the end of ablation, and the following day. C-reactive protein (CRP) levels were measured before ablation and the following day. RESULTS: Bidirectional isthmus block was achieved in all patients. Cryoablation showed significantly higher TnT following ablation (0.85 microg/l +/- 0.39 microg/l) compared to RF ablation (0.36 microg/l +/- 0.24 microg/l; p= 0.01) with declining levels the following day (cryoablation: 0.58 microg/l +/- 0.20 microg/l; RF ablation 0.34 microg/l +/- 0.21 microg/l; p= 0.03). We observed equal findings for CK and CKMB, both significantly higher in cryoablation. RF ablation led to a nonsignificant rise in CK and CKMB. CRP was elevated significantly higher following RF ablation (12.3 mg/dl +/- 4.1 mg/dl) compared to cryoablation (6.9 mg/dl +/- 4.0 mg/dl; p= 0.01). CONCLUSIONS: We show reduced inflammation despite higher markers for myocardial injury in cryoablation. The difference in biomarkers reflects different lesion formation in cryoablation and RF ablation. Cryoablation shows less systemic inflammatory reaction. This might be due to less endothelial damage and surface thrombosis in cryoablation.     

Predictors of VT/VF-occurrence in ICD patients: results from the PROFIT-Study.

AIMS: Identification of risk factors for ventricular tachycardia/ventricular fibrillation (VT/VF) occurrence in patients with implantable cardioverter-defibrillators (ICD) is reasonable, because ICD patients with multiple risk factors might benefit from more aggressive anti-arrhythmic therapy for the prevention of arrhythmic events. Furthermore, in the era of prophylactic ICD therapy and limited healthcare resources, additional markers are needed for improved patient selection. METHODS AND RESULTS: Thus, in Prospective Analysis of Risk Factor for Appropriate ICD Therapy (PROFIT), we prospectively analyzed the role of ejection fraction (EF), N-terminal probrain natriuretic peptide (NT-proBNP), New York Heart Association (NYHA) class, atrial fibrillation, and QRS-duration as independent predictors for VT/VF occurrence in 250 ICD patients. Kaplan-Meier analysis showed that EF<40% (log-rank P=0.001), NT-proBNP levels higher than median (>or=405 ng/L; log-rank P=0.04), QRS-duration >or=150 ms (log-rank P=0.016), permanent atrial fibrillation (log-rank P=0.008), and higher NYHA class (log-rank P=0.029) were associated with VT/VF occurrence. By multivariate Cox regression analysis EF, QRS-duration and atrial fibrillation remained significantly associated with appropriate VT/VF therapy, whereas there was no relationship among NT-proBNP, NYHA class, and VT/VF occurrence. Stratifying patients according to the number of their independent risk factors (EF<40%, AF, QRS-width>or=150 ms) showed that patients with greater than or equal to two risk factors had a 100% 2-year risk of VT/VF occurrence, whereas patients with no or one risk factor had a 19.3 and 25% 2-year risk, respectively. CONCLUSIONS: EF<40%, permanent atrial fibrillation, and QRS>or=150 ms are independent predictors for VT/VF occurrence in predominantly secondary prophylactic ICD patients. Combining all independent predictors, we developed a risk score for VT/VF occurrence identifying a subgroup of patients with two or more risk factors who had a 100% 2-year risk. Future studies will reveal if this risk score helps to identify ICD patients suitable for empirical anti-arrhythmic therapy and to improve patient selection for prophylactic ICD therapy.     

Sustained risk of recurrent thromboembolic events in patients with patent foramen ovale and paradoxical embolism: long-term follow-up over more than 15 years

Background  

Patients with patent foramen ovale (PFO) and cryptogenic stroke are at risk of recurrence. Therapeutic regimens range from no treatment to anticoagulation treatment to surgical or interventional closure. However, long-term follow-up is only available for up to 4 years.     

Cryoballoon pulmonary vein isolation temporarily modulates the intrinsic cardiac autonomic nervous system

Purpose  

Modulation of the intrinsic cardiac autonomic nervous system (ICANS) has been described to occur during radiofrequency pulmonary vein (PV) isolation for paroxysmal atrial fibrillation (AF) and has been controversially proposed to increase clinical success. Energy source used for PV isolation might influence ICANS modulation. The effect of balloon-delivered cryoenergy on the ICANS is unknown. We conducted a study investigating acute periprocedural effect on ICAN as well as changes in heart rate variability (HRV) for standard deviation of normal-to-normal intervals (SDNN) and triangular index (TI) as surrogates for ICANS modulation after cryoballoon PV isolation.     

Reduced delayed rectifier K+ current, altered electrophysiology, and increased ventricular vulnerability in MLP-deficient mice

BackgroundMice with a knockout (KO) of muscle LIM protein (MLP) exhibit many morphologic and clinical features of human cardiomyopathy. In humans, MLP-expression is downregulated both in ischemic and dilative cardiomyopathy. In this study, we investigated the effects of MLP on the electrophysiologic phenotype in vivo and on outward potassium currents.Methods and ResultsMLP-deficient (MLPKO) and wild-type (MLPWT) mice were subjected to long-term electrocardiogram (ECG) recording and in vivo electrophysiologic study. The whole-cell, patch-clamp technique was applied to measure voltage dependent outward K⁺ currents in isolated cardiomyocytes. Long-term ECG revealed a significant prolongation of RR mean (108 ± 9 versus 99 ± 5 ms), P (16 ± 3 versus 14 ± 1 ms), QRS (17 ± 3 versus 13 ± 1 ms), QT (68 ± 8 versus 46 ± 7 ms), QTc (66 ± 6 versus 46 ± 7 ms), JT (51 ± 7 versus 34 ± 7 ms), and JTc (49 ± 5 versus 33 ± 7 ms) in MLPKO versus MLPWT mice (P < .05). During EP study, QT (80 ± 8 versus 58 ± 7 ms), QTc (61 ± 6 versus 45 ± 5 ms), JT (62 ± 9 versus 43 ± 6 ms), and JTc (47 ± 5 versus 34 ± 5 ms) were also significantly prolonged in MLPKO mice (P < .05). Nonsustained VT was inducible in 9/16 MLPKO versus 2/15 MLPWT mice (P < .05). Analysis of outward K⁺ currents in revealed a significantly reduced density of the slowly inactivating outward K⁺ current IK, slow in MLPKO mice (11 ± 5pA/pF versus 18 ± 7pA/pF; P < .05).ConclusionMice with KO of MLP exhibit significant prolongation of atrial and ventricular conduction and an increased ventricular vulnerability. A reduction in repolarizing outward K⁺ currents may be responsible for these alterations.     

Comparison of N-terminal pro-brain natriuretic peptide versus electrophysiologic study for predicting future outcomes in patients with an implantable cardioverter defibrillator after myocardial infarction

The aim of the study was to examine the predictive value of N-terminal pro-brain natriuretic peptide (NT-pro-BNP) versus electrophysiologic study in patients with implantable cardioverter-defibrillators (ICDs) after myocardial infarction (MI). We prospectively studied 99 consecutive patients with a history of MI who underwent ICD implantation for primary or secondary prevention of sudden cardiac death. An electrophysiologic study was performed in all patients. Venous blood samples for NT-pro-BNP measurement were obtained at the beginning of the study. The primary end point was ventricular tachycardia or ventricular fibrillation (VT/VF) and the secondary end point was a composite of death, hospitalization for heart failure, or MI. On multivariate Cox regression analysis, NT-pro-BNP level at or greater than median (497 ng/L) was the only significant predictor for VT/VF occurrence (p = 0.047). Along with amiodarone use (p = 0.001), NT-pro-BNP levels higher than median were also associated with a higher risk of composite clinical events (p = 0.036). Kaplan-Meier analysis showed that patients with NT-pro-BNP level at or greater than median had a higher risk of experiencing VT/VF and composite clinical events than patients with NT-pro-BNP levels less than median (log-rank p <0.05). In conclusion, assay of NT-pro-BNP, which is easy to perform and widely available, is superior to electrophysiologic study for prediction of future outcomes in predominantly secondary prophylactic ICD recipients after MI. In the era of primary prophylactic ICD implantation without preimplantation electrophysiologic study, higher NT-pro-BNP levels might help to improve risk-adjusted concomitant antiarrhythmic therapy and device selection.