Frank Bode

Long‐Term Complication Rates in Ventricular, Single Lead VDD, and Dual Chamber Pacing

A higher incidence of pacemaker related complications has been reported in DDD systems as compared to VVI devices. The implantation of single lead VDD pacemakers might reduce the complication rate of physiological pacing in patients with AV block. In a retrospective study, the data records of 1,214 consecutive patients with pacemaker implantation for AV block between 1990 and 2001 (VVI 36.5%, DDD 32.9%, VDD 30.6%) were analyzed. Complications requiring surgical interventions were compared during a follow‐up period of 64 ± 31 months. Operation and fluoroscopic times were longer in DDD pacemaker implantation compared to VDD and VVI devices: 58 ± 23 versus 39 ± 10 and 37 ± 13  minutes   (P < 0.001), 9.2 ± 5.2 versus 4.1 ± 2.4 and 3.5 ± 2.3  minutes , respectively. Differences remained significant after correction for covariates. In a multivariate Cox regression model, the corrected complication hazard of a DDD pacemaker implantation was increased by 3.9 (1.4–11.3) compared to VVI and increased by 2.3 (1.1–4.5) compared to VDD pacing. Higher complication rates in DDD pacing were mainly due to a higher incidence of early reoperation for atrial lead dysfunction, whereas the long‐term complication rate was not different from VDD or VVI pacing. Early and long‐term complication rates did not differ between VDD and VVI pacemaker systems. In conclusion, operation time and complication rates of physiological pacing are reduced by VDD pacemaker implantation achieving values comparable to VVI pacing. Thus, single lead VDD pacing can be recommended for patients with AV block. (PACE 2003; 26:1961–1969)

Course and prognostic implications of QT interval and QT interval variability after primary coronary angioplasty in acute myocardial infarction

OBJECTIVES The aim of this study was to determine the influence of early reperfusion on the course of QT interval and QT interval variability in patients undergoing primary percutaneous transluminal coronary angioplasty (PTCA) in acute myocardial infarction (AMI) and its prognostic implications on major arrhythmic events during one-year follow-up. BACKGROUND Although early coronary artery recanalization by primary angioplasty is an established therapy in AMI, a substantial number of patients is still threatened by malignant arrhythmias even after early successful reperfusion, which may be caused by an inhomogeneity of ventricular repolarization despite reperfusion. METHOD Temporal fluctuations of ventricular repolarization were studied prospectively in 97 consecutive patients with a first AMI by measurements of QT interval and QT interval variability during and after successful PTCA (Thrombolysis in Myocardial Infarction flow grades 2 and 3). Continuous beat-to-beat QT interval measurement was performed from 24-h Holter monitoring, which was initiated at admission before PTCA. RESULTS Reperfusion caused a significant continuous increase of mean RR interval (738 +/- 98 to 808.5 +/- 121 ms; p < 0.001) and a significant decrease of parameters of QT interval (QTc: 440 +/- 32 to 416.5 +/- 37ms; p < 0.001) and QT interval variability (QTcSD: 27.5 +/- 3 to 24.9 +/- 6 ms; p < 0.001) in the majority of patients. However, in patients with major arrhythmic events at the one-year follow-up (sudden cardiac death, ventricular fibrillation or sustained ventricular tachycardia, n = 15), parameters of QT interval remained unaltered after successful reperfusion (QTc: 447.3 +/- 41 to 432.9 +/- 45 ms, p = NS; QTcSD: 35.1 +/- 13.4 to 29.0 +/- 9.1 ms, p = NS). CONCLUSIONS Reduction of QT interval and QT interval variability after timely reperfusion of the infarct-related artery may be a previously unreported beneficial mechanism of primary PTCA in AMI, indicating successful reperfusion.

Luminal esophageal temperature predicts esophageal lesions after second-generation cryoballoon pulmonary vein isolation

BACKGROUND The novel second-generation cryoballoon (CB) facilitates pulmonary vein isolation (PVI) by improved surface cooling. The impact of this redesign on collateral damage is unknown. OBJECTIVE To investigate the incidence of esophageal lesions after PVI using the second-generation CB and the role of luminal esophageal temperature (LET) measurement as a predictor of lesion formation. METHODS Thirty-two consecutive patients underwent PVI using the second-generation 28 mm CB. Target application time was 2 × 240 seconds. Ninety-two percent of the PVs were isolated after 1 cryoenergy application. Complete PVI was achieved in all patients. LET with 3 thermocouples was continuously measured during cryoenergy application. Freezing was interrupted only if weakening/loss of phrenic nerve function or low LET (<5 °C) was observed. RESULTS The lowest measured LET was-12 °C (despite cryoapplication interruption). Postprocedural gastroesophagoscopy was performed after 1-3 days in all patients and showed lesions in 6 of 32 (19%) patients. A minimum LET of≤12 °C predicted esophageal lesions with 100% sensitivity and 92% specificity (area under the receiver-operator characteristic curve 0.97; 95% CI 0.93-1.02; P = .001). Persistent phrenic nerve palsy occurred in 2 (6%) patients during ablation at the right inferior pulmonary vein. Repeat gastroesophagoscopy confirmed healing of lesions after 16 ± 14 days. CONCLUSIONS Second-generation 28 mm CB PVI is associated with significant esophageal cooling, resulting in lesion formation in 19% of the patients. LET measurement accurately predicts lesion formation and may enhance the safety of the novel device.

Mechano-electrical feedback underlying arrhythmias: the atrial fibrillation case.

Mechanoelectrical feedback (MEF) has become firmly established as a mechanism in which mechanical forces experienced by myocardial tissue or cell membranes convey alterations in electrophysiologic characteristics of such tissue. Observations to date mainly concern mechanically induced changes in action potential duration, resting and active potential amplitude, enhanced pacemaker frequency, or afterdepolarizations. While some of these changes (i.e. after depolarizations) may give rise to premature beats, a role of MEF in explaining sustained ventricular tachyarrhythmias has so far been elusive. Here, we review recent findings showing that acute atrial dilatation facilitates atrial fibrillation (AF) and that two stretch-activated channel (SAC) blockers (gadolinium and GsMTx-4) are able to suppress stretch-facilitated AF. These findings strongly support a role of MEF and SACs in promoting sustained arrhythmias and point to a new class of antiarrhythmic drugs.

Intra-operative defibrillation testing and clinical shock efficacy in patients with implantable cardioverter-defibrillators: the NORDIC ICD randomized clinical trial

Aims This trial was designed to test the hypothesis that shock efficacy during follow-up is not impaired in patients implanted without defibrillation (DF) testing during first implantable cardioverter-defibrillator (ICD) implantation. Methods and results Between February 2011 and July 2013, 1077 patients were randomly assigned (1 : 1) to first time ICD implantation with (n = 540) or without (n = 537) DF testing. The intra-operative DF testing was standardized across all participating centres, and all ICD shocks were programmed to 40 J irrespective of DF test results. The primary end point was the average first shock efficacy (FSE) for all true ventricular tachycardia and fibrillation (VT/VF) episodes during follow-up. The secondary end points included procedural data, serious adverse events, and mortality. During a median follow-up of 22.8 months, the model-based FSE was found to be non-inferior in patients with an ICD implanted without a DF test, with a difference in FSE of 3.0% in favour of the no DF test [confidence interval (CI) −3.0 to 9.0%, Pnon-inferiority <0.001 for the pre-defined non-inferiority margin of −10%). A total of 112 procedure-related serious adverse events occurred within 30 days in 94 patients (17.6%) tested compared with 89 events in 74 patients (13.9%) not tested (P = 0.095). Conclusion Defibrillation efficacy during follow-up is not inferior in patients with a 40 J ICD implanted without DF testing. Defibrillation testing during first time ICD implantation should no longer be recommended for routine left-sided ICD implantation.

Atrial sensing and AV synchrony in single lead VDD pacemakers: a prospective comparison to DDD devices with bipolar atrial leads.

Atrial Sensing and AV Synchrony in VDD and DDD Devices, Introduction: Single lead VDD pacing has offered an alternative to DDD systems in patients with isolated AV block. Up to now, however, the relative performance of these pacemaker systems was not systematically compared.

Reflex Cardiac Activity in Ischemia and Reperfusion Heart Rate Turbulence in Patients Undergoing Direct Percutaneous Coronary Intervention for Acute Myocardial Infarction

Background—Abnormal heart rate turbulence (HRT) is associated with an increased risk of mortality in the chronic phase of myocardial infarction (MI) in the prethrombolytic and thrombolytic eras. However, the impact of direct percutaneous coronary intervention (PCI) on HRT in the acute phase of MI and its association to the epicardial infarct-related arterial flow has not been examined. Methods and Results—We investigated HRT in 126 patients undergoing direct PCI for a first MI. Turbulence onset and turbulence slope were determined before reperfusion, during the initial 2 hours after reperfusion, and during hours 6 to 24 after reperfusion. HRT significantly improved after PCI. There were no significant differences in baseline clinical characteristics between Thrombolysis in Myocardial Infarction Trial classification (TIMI) 2 (n=28) and TIMI 3 (n=98) flow. After PCI, turbulence slope increased (13.2±11 to 18.1±12 ms/beat, P <0.001) and turbulence onset decreased (−0.008±0.04% to −0.023±0.04%, P <0.01) in patients with TIMI 3 flow after PCI, whereas there were no significant alterations of turbulence slope (12.2±10 to 12.8±6.5 ms/beat) and turbulence onset (−0.009±0.05% to −0.003±0.03%) in patients with TIMI 2 flow. Conclusions—The improvement of HRT after successful reperfusion is a previously unreported effect of direct PCI for acute MI, reflecting rapid restoration of baroreceptor response. The persistent impairment of HRT after PCI in patients with TIMI 2 flow indicates a sustained blunted baroreflex response and may reflect a more severe microvascular dysfunction.

Impact of Infarct-Related Artery Flow on QT Dynamicity in Patients Undergoing Direct Percutaneous Coronary Intervention for Acute Myocardial Infarction

Background—Complete coronary artery reperfusion in acute myocardial infarction (AMI) has been shown to significantly improve survival. Electrical stability may be the decisive mechanism for this beneficial effect. Because electrical stability is largely dependent on ventricular repolarization, we sought to determine the impact of a modern reperfusion strategy (ie, direct percutaneous coronary intervention [PCI]) on QT dynamicity in AMI and examined its association with infarct-related artery flow. Methods and Results—We prospectively investigated QT dynamicity in 128 patients undergoing direct PCI for a first AMI. Slopes and correlation coefficients of the linear QT/RR regression were determined in the time interval before reperfusion, within the initial hour after reperfusion, and within the remaining recording period from Holter ECG recordings, which were initiated on admission. Subgroup analysis based on TIMI 3 (n=100) and TIMI 2 (n=28) flow after PCI revealed no significant differences in QT/RR slope before PCI (0.145±0.12 versus 0.160±0.19, P =NS). After PCI, QT/RR slopes increased only in the TIMI 2 subgroup (P <0.05). In TIMI 2 patients, QT/RR slopes were significantly steeper in the hour after PCI and in the remaining recording period, respectively (0.155±0.12 versus 0.192±0.15, P <0.05, and 0.159±0.10 versus 0.210±0.17, P <0.01). Conclusions—Alterations of QT dynamicity in patients with incomplete reperfusion may suggest an altered electrical restitution, potentially providing a substrate for serious ventricular arrhythmias. Thus, our findings offer new insights into mechanisms by which complete reperfusion may affect electrical stability.

Catheter-based renal sympathetic denervation improves central hemodynamics and arterial stiffness: a pilot study.

J Clin Hypertens (Greenwich). 2012;14:861–870. ©2012 Wiley Periodicals, Inc.

Modulation of Ventricular Repolarization in Patients with Transient Left Ventricular Apical Ballooning: A Case Control Study

Objective: Even though diffuse T wave inversion and prolongation of the QT interval in the surface electrocardiogram (ECG) have been consistently reported in patients with transient stress‐induced left ventricular apical ballooning (AB), ventricular repolarization has not yet been systematically investigated in this clinical entity.