Cardiac resynchronisation therapy in patients with left bundle branch block with residual conduction.

AIM: To evaluate whether left bundle branch block with residual conduction (rLBBB) is associated with worse outcomes after cardiac resynchronisation therapy (CRT). METHODS: All consecutive CRT implants at our institution between 2006 and 2013 were identified from our local device registry. Pre- and post-implant patient specific data were extracted from clinical records. RESULTS: A total of 690 CRT implants were identified during the study period. Prior to CRT, 52.2% of patients had true left bundle branch block (LBBB), 19.1% a pacing-induced LBBB (pLBBB), 11.2% a rLBBB, 0.8% a right bundle branch block (RBBB), and 16.5% had a nonspecific intraventricular conduction delay (IVCD) electrocardiogram pattern. Mean age at implant was 67.5 years (standard deviation [SD] = 10.6), mean left ventricular ejection fraction (LV EF) was 25.7% (SD = 7.9%), and mean QRS duration was 158.4 ms (SD = 32 ms). After CRT, QRS duration was significantly reduced in the LBBB (p < 0.001), pLBBB (p < 0.001), rLBBB (p < 0.001), RBBB (p = 0.04), and IVCD groups (p = 0.03). LV EF significantly improved in the LBBB (p < 0.001), rLBBB (p = 0.002), and pLBBB (p < 0.001) groups, but the RBBB and IVCD groups showed no improvement. There was no significant difference in mortality between the LBBB and rLBBB groups. LV EF post-CRT, chronic kidney disease, hyperkalaemia, hypernatremia, and age at implant were significant predictors of mortality. CONCLUSION: CRT in patients with rLBBB results in improved LV EF and similar mortality rates to CRT patients with complete LBBB. Predictors of mortality post-CRT include post-CRT LV EF, presence of CKD, hyperkalaemia, hypernatremia, and older age at implant.

Release of high-sensitive TROPonin T by implantation of an entirely subcutaneous Implantable Cardioverter-defibrillator compared to a conventional transvenous approach: the TROPIC registry.

PURPOSE: Implantation of a subcutaneous implantable cardioverter-defibrillator (S-ICD) has become an alternative option when a conventional transvenous approach is not suitable. The myocardial damage caused by S-ICD implantation appears to be minimal despite mandatory defibrillation threshold (DFT) testing. However, there has not been a direct comparison with the traditional transvenous placement of a single-chamber ICD (VVI-ICD). The aim of this study was to determine the extent of myocardial damage by analysing the changes in serum levels of cardiac enzymes after S-ICD implantation in comparison with VVI-ICD. METHODS: In 43 patients who received an S-ICD system, differences in serum levels of high-sensitive troponin T (ΔhsTnT) and creatine kinase total (ΔCK) and muscle brain fraction (ΔCK-MB) were acquired by blood sampling before and the day after implantation. The control group consisted of 43 patients from the TropShock study who had received a transvenous VVI-ICD without DFT. RESULTS: After S-ICD implantation and testing procedure, ΔhsTnT (0.000 ng/ml, IQR - 0.003-0.002 ng/ml) was significantly lower than after conventional VVI-ICD implantation (0.018 ng/ml, IQR 0.004-0.032 ng/ml; p < 0.001). There was no significant difference in CK (ΔCKS-ICD 85.0 U/I, IQR 30.5-225.8 U/I vs ΔCKVVI-ICD 69.5 U/I, IQR 22.9-172.3 U/I; p = 0.357), but there was a significant difference in CK-MB (ΔCK-MBS-ICD of - 0.60, IQR - 2.60-1.0 vs ΔCK-MBVVI-ICD 1.0, IQR - 1.08-3.18; p = 0.030). CONCLUSION: S-ICD implantation causes less myocardial damage than VVI-ICD implantation evidenced by ΔhsTnT and ΔCK-MB.

Role of the Ambulatory Assessed Apnea-Hypopnea Index for Predicting Recurring Atrial Fibrillation After Ablation Therapy.

Catheter ablation is an effective treatment for atrial fibrillation (AF). Obstructive sleep apnea (OSA) is a known risk factor for recurrent AF. The apnea-hypopnea index (AHI) is a measurement tool to screen patients for OSA. We sought to evaluate if the ambulatory assessed AHI is associated with AF recurrence following AF catheter ablation. 187 patients with paroxysmal (n = 155) or early persistent (n = 32) AF presenting for catheter ablation were included in the study. AHI was determined prior to ablation using an ambulatory screening device. All patients underwent pulmonary vein isolation (PVI). In patients with early persistent AF (17%) additional ablation of complex fractionated atrial electrograms (CFAE) was performed. Clinical follow-up was available after 3 and 12 months including 7-day Holter-ECG. All 187 patients (60.3 ± 11.4 years, 64.2% male) completed the 3 months follow-up and 170 patients the 12 months follow-up. A pathological AHI ≥15 was found in 45/187 (24.1%) patients. Additional CFAE did not differ between patients with an AHI ≥15 and AHI <15 (p = 0.663). After 3 months, 12/41 (29.3%) patients with AHI ≥15 showed recurrent AF compared to 24/146 (16.4%) patients with AHI <15 (p = 0.066). After 12 months, AHI ≥15 was associated with a significant higher rate of AF recurrence of 47.4% (18/38) versus 26.5% (35/132) in patients with AHI <15 (p = 0.014). In the logistic regression analysis AHI ≥15 was an independent predictor of recurrent AF at 12 months (p = 0.011). In conclusion, ambulatory assessed AHI ≥15 is associated with increased risk for AF recurrence following catheter ablation. OSA screening should be performed in AF patients as it might influence catheter ablation success.

Security millimetre wave body scanner safe for patients with leadless pacemakers or subcutaneous implantable cardioverter-defibrillators.

PURPOSE: This study was designed to evaluate the electromagnetic interference (EMI) effects and safety of the new security screening millimetre wave body scanners (MWBSs) for patients with rare cardiac implantable electronic devices (CIEDs). METHODS: We identified 73 patients with either entirely subcutaneous implantable cardioverter-defibrillators (S-ICD) or leadless pacemakers (LPM) attending routine device follow-up. CIED programming was optimised for the detection of EMI occurrence, and high-voltage therapy was disabled. Patients then underwent millimetre wave body scans under continuous ECG monitoring. Scanning was performed at the recommended distance as well as in close proximity to the scanner emulating accidental exposure. CIED function was observed for EMI effects. RESULTS: There were no episodes of inhibition of pacing in the leadless pacemaker subgroup, no oversensing in the S-ICD subgroup and no spontaneous device reprogramming in any group. There was no change in pacing or sensing thresholds, and S-ICD vector eligibility remained unchanged after scanning with the MWBS. No CIEDs were identified by the MWBS during the study. CONCLUSION: No EMI events were detected during the use of MWBSs by patients with either S-ICDs or LPMs. This data should be reassuring for patients suggesting that they can undergo security body scans without worries or disclosure of their CIED status.

Myocardial Minimal Damage After Rapid Ventricular Pacing - the prospective randomized multicentre MyDate-Trial.

Therapy of choice for the primary and secondary prevention of sudden cardiac death is the implantation of an implantable cardioverter defibrillator (ICD). Whereas appropriate and inappropriate ICD shocks lead to myocardial microdamage, this is not known for antitachycardia pacing (ATP). In total, 150 ICD recipients (66 ± 12 years, 81.3% male, 93.3% primary prevention, 30.0% resynchronization therapy) were randomly assigned to an ICD implantation with or without intraoperative ATP. In the group with ATP, the pacing maneuver was performed twice, each time applying 8 impulses à 6 Volt x 1.0 milliseconds to the myocardium. High sensitive Troponin T (hsTnT) levels were determined prior to the implantation and thereafter. There was no significant difference in the release of hsTnT between the two randomization groups (delta TnT without ATP in median 0.010 ng/ml [min. -0.016 ng/ml-max. 0.075 ng/ml] vs. with ATP in median 0.013 ng/ml [min. -0.005-0.287 ng/ml], p = 0.323). Setting a hsTnT cutoff of 0.059 ng/dl as a regularly augmented postoperative hsTnT level, no relevant difference between the two groups regarding the postoperative hsTnT levels above this cutoff could be identified (without ATP n = 10 [14.7%] vs. with ATP n = 16 [21.9%], p = 0.287). There was no significant difference in the release of high sensitive Troponin between patients without intraoperative ATP compared to those with intraoperative ATP. Hence, antitachycardia pacing does not seem to cause significant myocardial microdamage. This may further support its use as a painless and efficient method to terminate ventricular tachycardia in high-risk patients.

Patients with pacemakers or defibrillators do not need to worry about e-Cars: An observational study.

BACKGROUND: Electric cars are increasingly used for public and private transportation and represent possible sources of electromagnetic interference (EMI). Potential implications for patients with cardiac implantable electronic devices (CIED) range from unnecessary driving restrictions to life-threatening device malfunction. This prospective, cross-sectional study was designed to assess the EMI risk of electric cars on CIED function. METHODS: One hundred and eight consecutive patients with CIEDs presenting for routine follow-up between May 2014 and January 2015 were enrolled in the study. The participants were exposed to electromagnetic fields generated by the four most common electric cars (Nissan Leaf, Tesla Model S, BMW i3, VW eUp) while roller-bench test-driving at Institute of Automotive Technology, Department of Mechanical Engineering, Technical University, Munich. The primary endpoint was any abnormalities in CIED function (e.g. oversensing with pacing-inhibition, inappropriate therapy or mode-switching) while driving or charging electric cars as assessed by electrocardiographic recordings and device interrogation. RESULTS: No change in device function or programming was seen in this cohort which is representative of contemporary CIED devices. The largest electromagnetic field detected was along the charging cable during high current charging (116.5 µT). The field strength in the cabin was lower (2.1-3.6 µT). CONCLUSIONS: Electric cars produce electromagnetic fields; however, they did not affect CIED function or programming in our cohort. Driving and charging of electric cars is likely safe for patients with CIEDs.

Incidence of magnet mode in patients with implantable cardioverter defibrillators.

PURPOSE: To determine the current incidence of antitachycardia therapy suspension due to magnet reversion in patients with implantable cardioverter defibrillators (ICDs). METHODS: From March 2012 to September 2018, all St. Jude Medical ICD interrogations performed at the Deutsches Herzzentrum München were screened for stored events of antitachycardia therapy suspension caused by static magnetic fields (flux densities ≥ 1 mT as defined in St. Jude Medical ICDs) affecting the giant magnetoresistance (GMR) sensor. Intentional ICD deactivation or inappropriate magnet application in the hospital was classified as non-environmental electromagnetic interference (EMI) whereas in the case of any other stored magnet reversion, the event was classified as presumably environmental EMI. RESULTS: Data from 201 St. Jude Medical ICD patients (mean age 62 ± 24 years, 165 males/36 females) were included in the analysis. ICD interrogations occurred at a mean follow-up of 25.1 months ± 15.6 months and summed up to a total of 464 patient-years of follow-up. A total number of 43 magnet reversion events were detected in 21 patients. Thirty-two events in 13 patients were presumably related to environmental EMI sources. Suspension of antitachycardia therapy only occurred in a temporary fashion. None of the patients experienced any ventricular tachyarrhythmia during ICD inhibition. The incidence of antitachycardia therapy suspension due to magnet reversion related to presumably environmental EMI sources was 6.9% per patient and year. CONCLUSION: Although none of the patients experienced any harmful event, antitachycardia therapy suspension due to magnet reversion is a common issue. Patients should be well-educated about potential EMI sources as well as trained in handling them.

The incidence, indications and predictors of acute pacemaker implantation after ablation of persistent atrial fibrillation.

INTRODUCTION: Patients with persistent atrial fibrillation (AF) may additionally suffer from a concealed sinus node disease. We sought to determine the incidence, indications and predictors of acute pacemaker [PM] implantation within 1 week after the ablation of persistent AF. METHODS AND RESULTS: We performed a retrospective analysis of patients, who had had an ablation of persistent AF at our center. Between 01/2011 and 08/2016, 1234 patients (mean age 65 ± 10 years, 66.7% male) without prior PM implantation underwent an ablation of persistent AF. Pulmonary vein isolation (PVI) was performed in 1158 (93.8%), the additional ablation of complex fractionated atrial electrograms (CFAE) in 1109 (89.9%) and linear ablation in 524 (42.5%) patients. Temporary cardiac pacing was necessary in 27 (2.2%) patients. The temporary PM was removed in 15 patients (1.2%) because sinus node recovered after a median of 1.0 (minimum 0.1-maximum 2.0) day. The remaining 12 (1.0%) patients required the implantation of a permanent PM. Another 13 (1.1%) patients required permanent PM implantation without prior temporary pacing. In a multivariable regression model, age [OR 1.07 (1.02-1.12), p = 0.006], sinus pauses prior to ablation [OR 7.97 (2.36-26.88), p = 0.001] and atria with low voltage [OR 2.83 (1.31-6.11), p = 0.008] were identified as significant predictors for acute cardiac pacing. CONCLUSION: Acute cardiac pacing within 1 week after the ablation of persistent AF was necessary in 40 (3.2%) patients. Age, sinus pauses in history prior to ablation and the existence of low-voltage areas in the atria were identified as relevant risk factors.

The impact of multipole pacing on left ventricular function in patients with cardiac resynchronization therapy - A real-time three-dimensional echocardiography approach.

BACKGROUND: Cardiac resynchronization therapy (CRT) is standard of care in heart failure (HF), however this technique is associated with a non-responder rate of 30%. Multipole pacing (MPP) with a quadripolar lead may optimize CRT and responder rate by creating two electrical wave fronts in the left ventricular (LV) myocardium simultaneously in order to reduce mechanical dyssynchrony. The objective of this study was to investigate the acute impact of MPP on LV function by assessing systolic dyssynchrony index (SDI) and left ventricular ejection fraction (LVEF) via real-time three-dimensional echocardiography (RT3DE). METHODS: In 41 consecutive patients (87.8% male; mean age 66.0 ±â€¯12.7 years) who received CRT defibrillators with a quadripolar LV lead, RT3DE datasets were acquired the day after implantation under the following pacing configurations: Baseline AAI, conventional biventricular pacing using distal or proximal LV poles and MPP. Datasets were analyzed in paired samples evaluating SDI and LVEF depending on programmed pacing modality. RESULTS: MPP resulted in statistically significant reduction of SDI compared to baseline (6.3%; IQR 4.4-7.8 and 9.9%; IQR 8.0-12.7; p < 0.001) and to conventional biventricular pacing using distal (7.6%; IQR 6.5-9.1; p < 0.001) or proximal (7.4%; IQR 6.2-8.8; p < 0.001) LV poles respectively. MPP yielded significant increase in LVEF compared to baseline (30.6%; IQR 25.8-37.5 and 27.2%; IQR 21.1-33.6; p < 0.001) and to conventional biventricular pacing configuration with distal (28.1%; IQR 22.1-34.5; p < 0.001) or proximal (28.6%; IQR 23.2-34.9; p < 0.001) LV poles respectively. CONCLUSIONS: Multipole pacing improves mechanical dyssynchrony of the left ventricular myocardium as assessed by SDI and LVEF.

Right Bundle Branch Block-Like Pattern During Uncomplicated Right Ventricular Pacing and the Effect of Pacing Site.

Right bundle branch block (RBBB) configuration is an unexpected finding during right ventricular (RV) pacing that raises the suspicion of inadvertent left ventricular lead positioning. The aim of this study was to evaluate the prevalence of paced RBBB pattern in relation to RV lead location. This is a secondary analysis of a prospective, multicenter study, which randomized implantable cardioverter defibrillator recipients to an apical versus midseptal defibrillator lead positioning. A 12-lead electrocardiogram was recorded during intrinsic rhythm and RV pacing. Paced RBBB-like pattern was defined as positive (>0.05 mV) net amplitude of QRS complex in leads V1 and/or V2. In total, 226 patients (65.6 ± 12.0 years, 20.8% women, 53.1% apical site) were included in the study. The prevalence of paced RBBB pattern in the total population was 15.5%. A significantly lower percentage of patients in the midseptal group demonstrated RBBB-type configuration during RV pacing compared with the apical group (1.9% vs 27.5%, p <0.001). Baseline RBBB, prolonged QRS duration during intrinsic rhythm, and reduced ejection fraction were not associated with increased likelihood of paced RBBB. In the subgroup of patients with RBBB type during pacing, 91.4% of patients had a paced QRS axis from -30° to -90°, whereas 100% of patients displayed a negative QRS vector at lead V3. In conclusion, RBBB configuration is encountered in a considerable percentage of device recipients during uncomplicated RV pacing. Midseptal lead positioning is associated with significantly lower likelihood of paced RBBB pattern compared with apical location.