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The 12-month follow-up (F/U) efficacy of CBA PVI performed at community hospitals for treatment of symptomatic paroxysmal and persistent atrial fibrillation (AF) is unknown. This study determined the 12-month efficacy of pulmonary vein isolation (PVI) using cryoballoon ablation (CBA) performed at community hospitals with limited annual case numbers.This registry study included 983 consecutive patients (pts) from 19 hospitals, each with an annual procedural volume of 100 PVI procedures/year. Pts underwent CBA PVI for paroxysmal AF (n = 520), persistent AF (n = 423), or redo PVI (n = 40). The primary endpoint was frequency of documented recurrent AF, the occurrence of atrial flutter or tachycardia following a 90-day period after the index ablation and up to 12 months. The frequency of repeat ablation was determined.Isolation of all PVs was documented in 98% of pts at the end of the procedure. Twelve-month F/U data could be obtained in 916 pts. A 24-h ECG registration was performed in 641 pts (70.0%); in 107 pts (16.7%) of them, recurrent AF was documented. The primary endpoint was met in 193 F/U pts (21.1%). It occurred in 80/486 F/U pts with paroxysmal AF (16.4%), and in 107/390 F/U pts with persistent AF (27.4%). Redo PVI was performed in 71 pts (7.8%), and atrial flutter ablation was performed in 12 pts (1.4%).CBA PVI for paroxysmal or persistent AF can be performed at community hospitals with adequate rates of 12-month symptom freedom and arrhythmia recurrence. The study was registered at the German register of clinical studies (DRKS00016504).

Background Pulmonary vein isolation (PVI) using cryoballoon ablation (CBA) has become an established and widespread procedure for the treatment of symptomatic paroxysmal and persistent atrial fibrillation (AF). The safety and efficacy of PVI at low and medium volume hospitals is unknown. Aim To determine safety and acute efficacy of PVI using CBA performed at community hospitals with limited annual case numbers. Methods This registry study prospectively included 1004 consecutive patients who underwent PVI with CBA for symptomatic paroxysmal (n=563) or persistent AF (n=441) between 01/2019 and 09/2020 at 20 community hospitals (each performing Results The mean annual number of CBA procedures performed was 59±26/hospital, the mean annual number of PVI performed regardless of the method used was 70±26/center. 8/20 hospitals performed CBA only. There were 22 operators (1,1/center), in 12/20 hospitals CBA was performed by an operator being board certified in invasive electrophysiology. 10/20 hospitals included 60 patients/hospital included a total of 623 pts (62%). Mean procedure time was 90.1±31.6 min, mean fluoroscopy time was 19.2±11.4 min. Isolation of all pulmonary veins could be achieved in 97.9% of patients. Not achieving the goal of “all veins isolated” in a respective patient was mainly due to early termination of CBA procedure due to phrenic nerve palsy. Major complications occurred in 1,2% of patients: no in-hospital death (0%), clinical stroke in 2 patients (0.2%), pericardial effusion requiring pericardial drainage in 2 patients (0,2%), vascular complications needing vascular surgery and/or blood transfusion in 2 patients (0,2%), phrenic nerve palsy persisting up to hospital discharge in 6 patients (0,6%). Minor complications occurred in 7,5% of patients: pericardial effusion with no need of intervention in 0,4%, access site complications with no need for therapeutic intervention or prolonged in-hospital stay in 2,1% (mainly superficial hematoma) and phrenic nerve palsy resolving before discharge in 4,2%. No significant difference in the number of complications could be found when testing for numbers of enrolled patients (> or < than 60/hospital) or regarding the board certification status of the operator. Conclusions PVI for paroxysmal or persistent AF using CBA can be performed at community hospitals with high acute efficacy and low complication rates despite low and moderate annual procedure numbers. Funding Acknowledgement Type of funding sources: None.

Background: Atrial arrhythmias are common in patients with implantable cardioverter-defibrillator (ICD). External shocks and internal cardioversion through commanded ICD shock for electrical cardioversion are used for rhythm-control. However, there is a paucity of data on efficacy of external versus internal cardioversion and on the risk of lead and device malfunction. We hypothesized that external cardioversion is noninferior to internal cardioversion for safety, and superior for successful restoration of sinus rhythm. Methods: Consecutive patients with ICD undergoing elective cardioversion for atrial arrhythmias at 13 centers were randomized in 1:1 fashion to either internal or external cardioversion. The primary safety end point was a composite of surrogate events of lead or device malfunction. Conversion of atrial arrhythmia to sinus rhythm was the primary efficacy end point. Myocardial damage was studied by measuring troponin release in both groups. Results: N=230 patients were randomized. Shock efficacy was 93% in the external cardioversion group and 65% in the internal cardioversion group ( P Conclusions: This is the first randomized trial on external vs internal cardioversion in patients with ICDs. External cardioversion was superior for the restoration of sinus rhythm. The unmasking of silent lead malfunction in the internal cardioversion group suggests that an internal shock attempt may be reasonable in selected ICD patients presenting for electrical cardioversion. Clinical Trial Registration: URL: https://www.clinicaltrials.gov . Unique identifier: NCT03247738.

Funding Acknowledgements Type of funding sources: None. OnBehalf REGIONAL Background Pulmonary vein isolation (PVI) using cryoballoon ablation (CBA) has become an established procedure for the treatment of symptomatic paroxysmal and persistent atrial fibrillation (AF). The safety and efficacy of PVI at community hospitals with low to moderate case numbers is unknown. Aim To determine safety and efficacy of PVI using CBA performed at community hospitals with limited annual case numbers. Methods 1004 PVI performed consecutively between 01/2019 and 09/2020 at 20 community hospitals (each Results Mean number of PVI using CBA/year was 59 ± 26. Mean procedure time was 90.1 ± 31.6 min and mean fluoroscopy time was 19.2 ± 11.4 min. Isolation of all pulmonary veins could be achieved in 97.9% of patients, early termination of CBA due to phrenic nerve palsy was the most frequent reason for incomplete isolation. There was no in-hospital death. 2 patients (0.2%) suffered a clinical stroke. Pericardial effusion occurred in 6 patients (0.6%), 2 of them (0.2%) required pericardial drainage. Vascular complications occurred in 24 patients (2.4%), in 2 of these patients (0.2%) vascular surgery was required. In 48 patients (4.8 %) phrenic nerve palsy was noticed which persisted up to hospital discharge in 6 patients (0.6%). Conclusions PVI for paroxysmal or persistent AF using CBA can be performed at community hospitals with high efficacy and low complication rates despite low to moderate annual procedure numbers.

Aims Pulmonary vein isolation (PVI) using cryoballoon ablation (CBA) is an established procedure for treating symptomatic paroxysmal and persistent atrial fibrillation (AF). The safety and efficacy of PVI performed at community hospitals are unknown. We aimed to determine the safety and acute efficacy of PVI using CBA performed at community hospitals with limited annual case numbers. Methods and results This registry study included 1004 consecutive patients who had PVI performed for symptomatic paroxysmal (n = 563) or persistent AF (n = 441) from January 2019 to September 2020 at 20 hospitals. Each hospital performed fewer than 100 CBA–PVI procedures/year according to local standards. Procedural data, efficacy, and complication rates were determined. The mean number of CBA procedures performed/year at each centre was 59 ± 25. The average procedure time was 90.1 ± 31.6 min and the average fluoroscopy time was 19.2 ± 11.4 min. Isolation of all pulmonary veins was documented in 97.9% of patients. The most frequent reason for not achieving complete isolation was development of phrenic nerve palsy. No hospital deaths were observed. Two patients (0.2%) suffered a clinical stroke. Pericardial effusion occurred in six patients (0.6%), two of whom (0.2%) required pericardial drainage. Vascular complications occurred in 24 patients (2.4%), two of whom (0.2%) required vascular surgery. Phrenic nerve palsy occurred in 48 patients (4.8%) and persisted up to hospital discharge in six patients (0.6%). Conclusion Pulmonary vein isolation procedures for paroxysmal or persistent AF using CBA can be performed at community hospitals with high acute efficacy and low complication rates.

Aims Current guidelines recommend opportunistic screening for atrial fibrillation (AF) but the prognosis of individuals is unclear. The aim of this investigation is to determine prevalence and 1-year outcome of individuals with screen-detected AF. Methods and results We performed a prospective, pharmacy-based single time point AF screening study in 7107 elderly citizens (≥65 years) using a hand-held, single-lead electrocardiogram (ECG) device. Prevalence of AF was assessed, and data on all-cause death and hospitalization for cardiovascular (CV) causes were collected over a median follow-up of 401 (372; 435) days. Mean age of participants was 74 ± 5.9 years, with 58% (N = 4130) of female sex. Automated heart rhythm analyses identified AF in 432 (6.1%) participants, with newly diagnosed AF in 3.6% of all subjects. During follow-up, 62 participants (0.9%) died and 390 (6.0%) were hospitalized for CV causes. Total mortality was 2.3% in participants with a screen-detected AF and 0.8% in subjects with a normal ECG [hazard ratio (HR) 2.94; 95% confidence interval (CI) 1.49–5.78; P = 0.002]; hospitalization for CV causes occurred in 10.6% and 5.5%, respectively (HR 2.08; 95% CI 1.52–2.84; P, Graphical Abstract

Funding Acknowledgements The investigators received an unrestricted research grant by Pfizer/BMS. Pfizer/BMS was not involved in the planning, conduct, analysis, or interpreta Background Recently, various devices specifically designed to automatically detect atrial fibrillation, became available. Utility of automated atrial fibrillation detection in mass-screening remains unclear, because accuracy and validation of automated AF detection were mostly tested retrospectively in preselected cohorts with high atrial fibrillation prevalence. Purpose The aim of this analysis was to determine the accuracy of automated atrial fibrillation detection by a single-lead hand-held ECG device in a prospective population-based screening approach with several thousand subjects. Methods For automated atrial fibrillation detection, we investigated the MyDiagnostick a 30 cm long hand-held ECG-stick. All customers aged 65 years or older in the pharmacies were eligible to participate. After informed consent was obtained, a one-minute single-lead ECG was recorded by trained staff. Five levels of human ECG expert validation were performed to determine heart rhythm. All recorded unfiltered ECGs (Figure 1) were analyzed at least by two independent, blinded investigators, in case of an automated AF detection by at least 3 independent, blinded investigators. In case of contradiction in the first three levels of heart rhythm assessment, ECGs were analyzed in level 4 by two independent cardiologists. In level 5 all single-lead ECGs were unblinded and any single-lead ECG with a contradiction between the human ECG expert results and the automated ECG-Stick result were analyzed by a rhythm consortium consisting of 3 cardiologists. Final results for heart rhythm and ECG quality were stipulated by a hierarchical approach, whereas results in higher levels of analysis vote down results in earlier levels of analysis in case of a contradiction. Results In total, 7209 single-lead ECGs were available for analysis. The mean age was 74 ± 6 years, 42% (N = 3049) of participants were male, mean CHA2DS2-VASc score was 3.3 ± 1.4. We identified 5.3% (N = 383) patients with atrial fibrillation identified by human investigators. The ECG-Stick diagnosed 79% (N = 304) of the atrial fibrillation patients correctly. In 21% (N = 79/383) the result was false-negative, and in 1% (N = 72/7209) false-positive. In another 1% (N = 81/7209) single-lead ECG recordings were uninterpretable by expert investigators, although the automated analysis provided a result (SR: 27, atrial fibrillation: 54). Using final level results by expert ECG reading as reference, automated ECG-Stick analysis showed good prediction in receiver operating calculation of atrial fibrillation with an area under the curve of 0.89, sensitivity: 80%, specificity: 98%, and a good interclass correlation coefficient of 0.75, 95%CI (0.74; 0.76)). Conclusions The results encourage the implementation of single-lead ECG devices for automated atrial fibrillation screening. A rhythm diagnosis by single-lead ECG seems possible for recordings with excellent ECG signal quality. Abstract Figure. Single-lead ECG example (5 of 60 sec)

Background Atrial fibrillation (AF) is the most common arrhythmia associated with increased morbidity and mortality. Current guidelines recommend opportunistic screening for AF but the prognostic impact of screen-detected AF is unclear. Methods We performed a 4-week, prospective, pharmacy-based AF screening study in 7107 elderly citizens (≥65 years) using a hand-held, automated, one-minute single-lead ECG (SL-ECG) recording device. Prevalence and incidence of AF was assessed, and data on all-cause death and hospitalization for cardiovascular (CV) causes were collected over a median follow-up of 401 (372; 435) days. Results Automated SL-ECG analyses revealed heartbeat irregularities suspicious of AF in 432 (6.1%) participants with newly diagnosed AF in 3.6% of all subjects. During follow-up, 62 participants (0.9%) died and 390 (6.0%) were hospitalised for CV causes. Total mortality was 2.3% in participants with a SL-ECG suspicious of AF and 0.8% in subjects with a normal SL-ECG (HR 2.93; 95% CI: 1.49, 5.77; P=0.002, Figure 1A); hospitalization for CV causes occurred in 10.6% and 5.5%, respectively (HR 2.08; 95% CI: 1.52, 2.84; P Figure 1 Conclusions Pharmacy-based, automated, one-minute SL-ECG screening in elderly citizens identified subjects with unknown AF and an excess mortality risk over the next one year. Acknowledgement/Funding Unrestricted research grant by Pfizer/BMS. Matthias Zink received a DGK electrophysiology grant (funded by St. Jude Medical).

Der oralen Antikoagulation kommt bei Patienten mit Vorhofflimmern eine entscheidende Rolle zu, da sie bei den meisten Patienten zur Reduktion des Schlaganfallrisikos indiziert ist. Sinnvoll ist eine Abschatzung des Schlaganfallrisikos mit Hilfe des CHA2DS2-VASc-Scores und des Blutungsrisikos anhand des HAS-BLED-Scores. Die orale Antikoagulation ist prinzipiell indiziert bei allen Patienten mit valvularem Vorhofflimmern (Vorhofflimmern bei relevanter Mitralklappenstenose oder Kunstklappe) sowie bei Patienten mit nicht-valvularem Vorhofflimmern ab einem CHA2DS2-VASc-Score von 1 – 2 Punkten. Die Indikation erfolgt zumeist unabhangig davon, ob Vorhofflimmern paroxysmal, persistierend oder permanent auftritt. Nicht-Vitamin-K-Antagonisten (NOAK) stellen fur viele Patienten die Therapie der ersten Wahl dar. Die Wahl des geeigneten Antikoagulans sollte in Abhangigkeit von Patienten- und Arztpraferenz anhand weiterer Faktoren wie Niereninsuffizienz, Ko-Medikation und Blutungsrisiko erfolgen. Insbesondere fur Patienten mit Kontraindikation fur eine orale Antikoagulation stellt der interventionelle Vorhofohrverschluss eine Therapiealternative dar.

BioMed research international 2015, 840356 (2015). doi:10.1155/2015/840356, Published by Hindawi, New York [u.a.]

A relevant number of patients presenting for electrical cardioversion carry a pacemaker (PM) or ICD. Case reports suggest a potential hazard of external cardioversion/defibrillation. The incidence of shock related device complications is unknown. No guidelines or recommendations by international medical societies for a cardioversion protocol of cardiovascular implantable electronic device (CIED) patients exist. We conducted a nationwide survey to gather real-world clinical data on the current clinical approach towards these patients during electrical cardioversion and to estimate the incidence of shock-related complications. Ninety hospitals with > 380 ECV in 2014 were identified from mandatory hospital quality reports and 60 were randomly selected. All centers were provided with a standardized questionnaire on the general proceedings and complications during electrical cardioversion of pacemaker, ICD and CRT patients (CIED patients). Thirty-two centers (53%) participated in the survey. In total, 16,554 ECV were reported (534 ± 314 per center). Biphasic cardioversion with a first shock energy of ≥ 150 J via adhesive patches in antero-posterior orientation was preferred by most centers (78%). Eleven percent (n = 1809) of pts were reported to carry a PM/ICD. The ECV protocol was heterogeneous among centers. Complications associated with electrical cardioversion were reported in 11/1809 patients (0.6%), all were transitory elevations of pacing thresholds. In this nationwide snapshot survey of cardioversion procedures in Germany, approximately 11% of patients presenting for elective electrical cardioversion were pacemaker or ICD carriers. Cardioversion protocols in these patients are heterogeneous throughout centers and mostly not in accordance with recommendation of the German Cardiac Society. Complications associated with external electrical cardioversion are rare. Controlled trials and large registries are necessary to provide evidence for future recommendations.

A simplification of Pijls’ formula to calculate the predicted fractional flow reserve (FFR) in sequential coronary stenosis without balloon inflation is hereby proposed. In patients with an indication for FFR and sequential coronary stenosis, FFR was recorded distally and between the lesions. The

Hochdruckerkrankungen tragen weltweit entscheidend zu Morbiditat und Mortalitat bei. Nach wie vor ist es fur den behandelnden Arzt eine besondere Herausforderung, den Patienten von der Notwendigkeit der Therapie einer haufig asymptomatischen Erkrankung zu uberzeugen. Vor der Therapieeinleitung ist eine basisdiagnostische Abklarung auch hinsichtlich des Vorliegens einer sekundaren (moglicherweise anders therapeutisch zuganglichen) Hypertonie essenziell. Insbesondere bei jungen Patienten als auch bei fehlender Nachtabsenkung sollte eine ausfuhrliche Abklarung mit Anamneseerhebung und Labordiagnostik sowie Abklarung einer renalen oder endokrinologischen Ursache erfolgen. Weitere Faktoren wie Lebensstil, fehlende Adharenz, aber auch eine Schlafapnoe sollten in die differenzialdiagnostischen Uberlegungen einbezogen werden. Zudem sollte das gesamte kardiovaskulare Risiko abgeschatzt werden durch Diagnose von anderen Risikofaktoren, Endorganschaden und Begleiterkrankungen.

Congestive heart failure is frequent and leads to reduced exercise capacity, reduced quality of life (QoL), and depression in many patients. Cardiac resynchronization therapy (CRT) and implantable cardioverter defibrillators (ICD) offer therapeutic options and may have an impact on QoL and depression. This study was performed to evaluate physical and mental health in patients undergoing ICD or combined CRT/ICD-implantation (CRT-D). Echocardiography, spiroergometry, and psychometric questionnaires [Beck Depression Inventory, General World Health Organization Five Well-being Index (WHO-5), Brief Symptom Inventory and 36-item Short Form (SF-36)] were obtained in 39 patients (ICD: 17, CRT-D: 22) at baseline and 6-month follow-up (FU) after device implantation. CRT-D patients had a higher NYHA class and broader left bundle branch block than ICD patients at baseline. At FU, ejection fraction (EF), peak oxygen uptake, and NYHA class improved significantly in CRT-D patients but remained unchanged in ICD patients. Patients with CRT-D implantation showed higher levels of depressive symptoms, psychological distress, and impairment in QoL at baseline and FU compared to ICD patients. These impairments remained mostly unchanged in all patients after 6 months. Overall, these findings imply that there is a need for careful assessment and treatment of psychological distress and depression in ICD and CRT-D patients in the course of device implantation as psychological burden seems to persist irrespective of physical improvement.

Three-dimensional (3D)-imaging provides important information on cardiac anatomy during electrophysiological procedures. Real-time updates of modalities with high soft-tissue contrast are particularly advantageous during cardiac procedures. Therefore, a beat to beat 3D visualization of cardiac anatomy by intracardiac echocardiography (ICE) was developed and tested in phantoms and animals. An electronic phased-array 5-10 MHz ICE-catheter (Acuson, AcuNav (TM)/Siemens Medical Solutions USA/64 elements) providing a 90A degrees sector image was used for ICE-imaging. A custom-made mechanical prototype controlled by a servo motor allowed automatic rotation of the ICE-catheter around its longitudinal axis. During a single heartbeat, the ICE-catheter was rotated and 2D-images were acquired. Reconstruction into a 3D volume and rendering by a prototype software was performed beat to beat. After experimental validation using a rigid phantom, the system was tested in an animal study and afterwards, for quantitative validation, in a dynamic phantom. Acquisition of beat to beat 3D-reconstruction was technically feasible. However, twisting of the ICE-catheter shaft due to friction and torsion was found and rotation was hampered. Also, depiction of catheters was not always ensured in case of parallel alignment. Using a curved sheath for depiction of cardiac anatomy there was no congruent depiction of shape and dimension of static and moving objects. Beat to beat 3D-ICE-imaging is feasible. However, shape and dimension of static and moving objects cannot always be displayed with necessary steadiness as needed in the clinical setting. As catheter depiction is also limited, clinical use seems impossible.

Oral anticoagulation plays an essential role in the treatment of patients with atrial fibrillation as it is indicated for most patients to reduce the risk of stroke. It is prudent to assess the risks of stroke and bleeding using the CHA

Hypoglycaemia is associated with increased risk of cardiovascular events and mortality in patients with diabetes, but the extent and mechanisms of this link are ill defined. We here prospectively studied cardiac repolarization abnormalities during insulin-induced hypoglycaemia in humans.119 individuals (69 males, age 47.5±13.4years, range 18-82years) were assessed during hypoglycaemia after the injection of 0.1-0.25units/kg human insulin. Corrected QT intervals (QTc) and QT dispersion (QTd) were calculated from serially recorded twelve lead electrocardiograms, and plasma glucose and other endocrine markers were studied.QTc increased from 415.1±21.9ms (mean±standard deviation) at baseline to 444.9±26.5ms during hypoglycaemia (plasma glucose nadir, 1.6±0.5mmol/L, p=0.001), accompanied by an increase of QTd from 45.0±22.7ms to 64.1±40.0ms (p0.001). Hypoglycaemia-induced abnormal QTc prolongation (defined as ⩾460ms in females and ⩾450ms in males) occurred in 17% (9/54) of females and 26% (17/65) of males. 97 of 119 of individuals (82%) developed transient hypokalaemia (KInsulin-induced hypoglycaemia frequently causes abnormal QT prolongation and is associated with hypokalaemia and sympathoadrenal activation, thereby increasing the potential risk for ventricular arrhythmias, particularly in individuals with pre-existing high normal QTc.

An irregular ventricular response during atrial fibrillation (AF) has been shown to mediate an increase in sympathetic nerve activity in human subjects. The molecular mechanisms remain unclear. This study aimed to investigate the impact of rate and irregularity on nerve growth factor (NGF) expression in cardiomyocytes, since NGF is known to be the main contributor to cardiac sympathetic innervation density. Cell cultures of neonatal rat ventricular myocytes were electrically stimulated for 48 h with increasing rates (0, 5 and 50 Hz) and irregularity (standard deviation (SD)=5%, 25% and 50% of mean cycle length). Furthermore, we analyzed the calcineurin-NFAT and the endothelin-1 signalling pathways as possible contributors to NGF regulation during arrhythmic stimulation. We found that the increase of NGF expression reached its maximum at the irregularity of 25% SD by 5 Hz (NGF: 5 Hz 0% SD=1 vs. 5Hz 25% SD=1.57, P

Background Recently, increased cardiac norepinephrine levels were observed in patients who were exposed to irregular stimulation during electrophysiological testing. The molecular mechanisms remain unclear. Intrinsic cardiac adrenergic (ICA) cells are present in mammalian hearts and contain catecholamine-synthesizing enzymes sufficient to produce biologically active norepinephrine levels. Thus, we aimed to investigate the expression of catecholamine-synthesizing enzymes by ICA cells exposed to irregular pacing. Methods Co-cultures of cardiomyocytes and ICA cells were exposed to irregular pacing for 48 h (standard deviation (SD) = 5%, 25% and 50% of mean cycle length) at a constant rate of 5 Hz. The expression of catecholamine-synthesizing enzymes including tyrosine hydroxylase (TH) and dopamine beta hydroxylase (DBH) were analyzed on mRNA and protein levels. Results First, immunolabeling identified ICA cells presenting TH and DBH staining around the cell nucleus. Irregular pacing with 25% SD at a constant rate of 5 Hz significantly increased the expression of TH and DBH enzyme synthesis. Pharmacological approaches have shown that both metoprolol and losartan reversed the irregular pacing induced DBH increase, whereas the expression of TH was only blocked by metoprolol in a significant manner. Blockade of the endothelin-A receptor by BQ123 or the calcineurin–NFAT pathway by cyclosporine-A, 11R-VIVIT or FK506 revealed a potential role of both cascades in irregular pacing induced catecholamine-synthesizing enzyme expression. Conclusions ICA cells respond to irregular electrical activation with an increase in catecholamine-synthesizing enzymes. Drugs commonly used in clinical routine significantly influence the expression of TH and DBH by ICA cells via different signaling routes.

Introduction Cardiac resynchronization therapy (CRT) provides a therapeutic option for patients with congestive heart failure (CHF) and left bundle-branch block. Structural myocardial remodelling due to CRT has been described extensively. We hypothesized that CRT might also induce electrical remodelling, thus decreasing the intrinsic QRS duration. Methods: In 38 patients with CHF (ejection fraction (EF): 26 ± 7%) a CRT device was implanted. 18 patients suff ered from ischaemic cardiomyopathy (ICM) and 20 from dilated cardiomyopathy (DCM). Echocardiography and 12-lead ECGs without pacing were obtained prior to implantation and after 6 and 12 months. Patients were classifi ed as responders in case of an increase in EF ≥ 25% in combination with an increase in NYHA class ≥ 1. Variance analysis was performed to determine the impact of response or underlying heart disease (ICM/DCM) on the extent of change in QRS duration (delta QRS duration). Results: The EF increased to 36 ± 10% (P < 0.0001) after 6 months and 40 ± 12% (P < 0.0001) after 12 months of CRT. Intrinsic QRS duration decreased from 171 ± 18 ms before CRT to 164 ± 23 ms (P= 0.027) after 6 months and 161 ± 25 ms (P= 0.002) after 12 months of CRT. 22 patients (58%) were classifi ed as responders. Whereas a signifi cant decrease in intrinsic QRS duration was observed in responders, only a slight decrease was seen in non-responders. However, two-factorial variance analyses did not show a signifi cant infl uence of response or underlying heart disease (ICM/DCM) on delta QRS duration (P= 0.7). Conclusion: CRT results in an electrical remodelling with a reduction of the intrinsic QRS duration.

Objective: Current alternative approaches for pacemaker lead implantation imply the breach of the pleural space. Recently, the feasibility of experimental lead implantation by rigid endoscopy has been described. The use of flexible endoscopes and a standardised application has not been realised yet. Our main goal was to compare rigid andflexible endoscopy and to establish a standardisedprotocol for the implementation of a closed-chest subxiphoid approach for epimyocardial lead implantation. Methods: Rigid and flexible endoscopes were used for placement of screw-in pacingleads (4-F). A total of 17 adult pigs (80 kg) were anaesthetised and a 10-mm subxiphoid axial incision performed. The pericardium was opened and entered under endoscopic vision. Epimyocardial electrodes were implanted through the endoscope onto all four chambers. Standard haemodynamic measurements and pacing measurements were carried out. Results: Both methods were deployed in the first three individuals. Superior endorsement of rigid endoscopy, due to better orientation and stability, led to its exclusive deployment in the remaining 14 individuals. Access to the implantation sites was quick (

Background— Electric stimulation of mediastinal sympathetic cardiac nerves increases cardiac contractility but is not selective for the left ventricle because it elicits sinus tachycardia and enhanced atrioventricular conduction. The aim of this study was to identify sympathetic neural structures inside the heart that selectively control left ventricular inotropy and can be accessed by transvenous catheter stimulation. Methods and Results— In 20 sheep, high-frequency stimulation (200 Hz) during the myocardial refractory period with electrode catheters inside the coronary sinus evoked a systolic left ventricular pressure increase from 97±20 to 138±32 mm Hg ( P P =0.004) and rate of diastolic relaxation (531±128 versus 888±331 mm Hg/s; P =0.001) increased. The slope of the end-systolic pressure-volume relationship increased (2.3±0.8 versus 3.1±0.6 mm Hg/mL; P =0.04), as did cardiac output (3.5±0.8 versus 4.4±0.8 L/min; P Conclusions— Cardiac nerve fibers that innervate the left ventricle are amenable to transvenous electric catheter stimulation. This may permit direct interference with and modulation of the sympathetic tone of the left ventricle.

Long-Term Cardiac Neurostimulation.Introduction: The right inferior ganglionated plexus (RIGP) selectively innervates the atrioventricular node. Temporary electrical stimulation of this plexus reduces the ventricular rate during atrial fibrillation (AF). We sought to assess the feasibility of chronic parasympathetic stimulation for ventricular rate control during AF with a nonthoracotomy intracardiac neurostimulation approach. Methods and Results: In 9 mongrel dogs, the small endocardial area inside the right atrium, which overlies the RIGP, was identified by 20 Hz stimulation over a guiding catheter with integrated electrodes. Once identified, an active-fixation lead was implanted. The lead was connected to a subcutaneous neurostimulator. An additional dual-chamber pacemaker was implanted for AF induction by rapid atrial pacing and ventricular rate monitoring. Continuous neurostimulation was delivered for 1–2 years to decrease the ventricular rate during AF to a range of 100–140 bpm. Implantation of a neurostimulation lead was achieved within 37 ± 12 min. The latency of the negative dromotropic response after on/offset or modulation of neurostimulation was

During atrial fibrillation, arterial hypertension and systolic or diastolic heart failure, atrial myocytes are exposed to increased baseline stretch. Atrial stretch has been shown to induce cellular hypertrophy and extracellular matrix remodeling (ECM) via angiotensin-II dependent pathways and the matrix metalloproteinases system (MMPs). We hypothesized that atrial myocytes exposed to static stretch may increase their ECM remodeling activity via up-regulation of MMP-2/-9. We then tested the hypothesis that the membrane bound angiotensin-II type 1 (AT1) receptor and the intracellular calcineurin (Cn)-NFAT signaling pathway are potential mediators of stretch-induced MMP alterations, since Cn-NFAT is one important contributor to myocyte hypertrophy.Neonatal rat atrial myocytes (NRAM) were cultured under conditions of static stretch by 21%. The differential effects of selective AT1 receptor blockade by losartan, Cn blockade by Cyclosporine-A (CsA) or NFAT inhibition by 11R-VIVIT (VIV), were analyzed. Stretch resulted in a significant up-regulation of active-MMP-2/-9 protein amount (active-MMP-2 ng/microg: control 8.95 +/- 0.64 vs. stretch 13.11 +/- 0.74 / active-MMP-9 ng/microg: control 1.45 +/- 0.18 vs. stretch 1.94 +/- 0.21, all n = 5) and enzyme activity (MMP-2 in %: control 1 +/- 0.0 vs. stretch 1.87 +/- 0.25, n = 7) associated with a significant increase of the membrane-type-1-MMP (MT1-MMP) protein expression (MT1-MMP in %: control 1 +/- 0.0 vs. stretch 2.17 +/- 0.21, n = 8). These observations were accompanied by an activation of the Cn-NFAT pathway (Cn-activity in nmol PO(4) release/20 microg protein/30 min: control 0.37 +/- 0.08 vs. stretch 0.65 +/- 0.09, n = 3 / NFATc1-DNA binding activity in %: control 1 +/- 0.0 vs. stretch 1.53 +/- 0.17, n = 3). Losartan, CsA or VIV abolished stretch-induced alterations in MMP-2/-9 and MT1-MMP expression and enzyme activity by normalizing the Cn-activity and the DNA binding activity of NFATc1.Our results present new insights in molecular mechanisms of ECM remodeling activity of atrial myocytes exposed to static stretch. The AT1-Cn-NFAT pathway is a potential mediator of MMP activation.

Cardioversion (CV) success of atrial fibrillation (AF) inversely correlates to the size of the left atrium (LA). Atrial fibrillation and its most important risk factor, congestive heart failure (CHF), both induce atrial structural enlargement and fibrosis. To investigate the effect of AF and CHF on atrial dilatation and fibrosis, and to estimate whether echocardiographically determined atrial size may be used as a marker for atrial fibrosis.In six dogs, pacemakers were implanted followed by HIS bundle ablation. After 4 weeks of rapid ventricular stimulation (185 bpm) for CHF induction, additional rapid atrial stimulation (500 bpm) was maintained for 7 weeks to induce AF. Serial determinations of echocardiographic atrial size were performed. Seven dogs with sinus rhythm served as histological controls. Postmortem tissue was obtained to determine the degree and composition of atrial fibrosis.While the ejection fraction of the AF/CHF dogs decreased significantly from 57+/-5% to 19+/-7% (P.01), an increased degree of atrial fibrosis was found (right atrium [RA], 4.9+/-2.0% to 19.9+/-5.4%; LA, 4.4+/-1.6% to 22.2+/-3.2%; P.01), accompanied by a significant increase of atrial volumes (LA: 21+/-4 to 44+/-4 mm3; P.01; RA: 10+/-3 to 18+/-6 mm3; P.05) and LA diameters (34+/-4 to 43+/-2 mm, P.05). Atrial fibrosis and size significantly correlated.Atrial fibrillation/CHF leads to a significant atrial fibrosis and dilation. The increased echocardiographic size correlates to the degree of atrial fibrosis and may be used as clinical marker for atrial fibrosis. The fibrosis accompanying atrial dilatation may also explain why LA size, as determined by echocardiography, is a strong predictor of CV success.

Background: Hospitalizations due to decompensation are a frequent problem in treating patients with congestive heart failure (CHF). Continuous impedance measurement via implantable devices may detect pulmonary fluid accumulation due to worsening CHF. An acoustic alert might allow an earlier treatment of impending decompensation. An algorithm that implemented impedance measurement into clinical decision making in treating CHF patients was evaluated. Methods: Forty-two CHF patients (ejection fraction: 27 ± 6%; New York Heart Association 2.9 ± 0.6) with cardiac resynchronization therapy and automatic impedance measurements were included. Upon an alert, a stepped therapy was initiated: category (1) overt decompensation, hospitalization; category (2) worsened CHF, increase of diuretics; category (3) no CHF worsening, brain natriuretic peptide (BNP) measurement, elevated BNP: increase of diuretics, normal BNP: no specific treatment. Results: During 18 ± 4 months, 45 alerts were treated according to the algorithm. Eleven category 1 alerts led to hospitalization; 21 category 2 and 11 category 3 patients (elevated BNP) were treated conservatively. Two category 3 alerts (normal BNP) received no treatment. Conclusions: Automatic impedance measurement can be integrated into CHF management. BNP measurement restricted to patients with alert but without clinical signs of worsened CHF may prevent premature therapy escalation.

Information on the anatomy of the cardiac venous system (CVS) is increasingly important for cardiac resynchronization therapy or percutaneous transvenous mitral valve annuloplasty. Three-dimensional (3D) imaging can further improve the understanding of the relationship of cardiac structures. This study was performed to validate the accuracy of rotational coronary sinus angiography (CSA) displaying the 3D anatomy of the CVS compared to ECG-gated, contrast-enhanced, cardiac dual-source computed tomography (DSCT). Five domestic pigs (60 kg) underwent DSCT using a standardized examination protocol. Using a standard C-arm for fluoroscopy, a rotational CSA was obtained and 3D-image reconstructions performed. Side branches were identified using both methods and enumerated. Vessel visibility was estimated for each side branch and great cardiac vein/anterior interventricular vein. Also, vessel diameters were measured at distinct landmarks, i.e., side branching. The amount of contrast medium was determined and the effective radiation exposure of both methods was calculated. There was no significant difference regarding the vessel diameter of the great cardiac vein/anterior interventricular vein or its side branches. Also, estimation of vessel visibility was not different between the two imaging modalities. Estimated radiation exposure and amount of contrast medium were lower for rotational CSA. In conclusion, a 3D reconstruction of rotational CSA images is possible. All parts of the CVS are well depicted, allowing a 3D overview of the CVS anatomy. On-site 3D visualization might improve decision making during cardiac interventions. In contrast to DSCT, rotational CSA does not demonstrate the anatomy of the mitral annulus or the course of the left circumflex artery.

Introduction: Increasing duration of ventricular fibrillation (VF) is associated with a higher risk of ineffective resuscitation. In addition, precountershock chest compression can influence defibrillation success. Transesophageal defibrillation may increase defibrillation success because of the proximity of the esophagus to the heart. We evaluated the efficacy of transesophageal defibrillation compared with standard transthoracic defibrillation after long episodes of VF. Methods: Defibrillation success after 10 minutes of untreated VF was evaluated in 12 sheep randomized into 2 groups: (group A) in 6 sheep, up to 3 transthoracic shocks were applied, followed by up to 3 transesophageal shocks (first shock: 150 J, second and third shocks: 200 J). (group B) In 6 sheep, 2 minutes of precountershock chest compression preceded the defibrillation shocks. Truncated biphasic shocks were delivered between a sternal and an apical patch electrode for transthoracic defibrillation and between an esophageal and a cutaneous patch electrode for transesophageal defibrillation. Results: In group A with no precountershock chest compression, external defibrillation failed despite shocks with maximum energy (200 J) in all 6 sheep. Transesophageal defibrillation was successful in 3 sheep (50%). In group B with precountershock chest compression, external defibrillation failed in all 6 sheep. Transesophageal defibrillation was successful with the first shock in all 6 sheep. Conclusions: Transesophageal defibrillation may terminate VF of long duration that is refractory to standard defibrillation. Precountershock chest compression may increase transesophageal defibrillation success.

Defibrillation thresholds (DFT) are lower when using biphasic instead of monophasic shock waveforms. In addition, transesophageal defibrillation can decrease the defibrillation threshold compared to thransthoracic defibrillation due to a different shock vector. We compared the defibrillation thresholds of a monophasic and three biphasic defibrillators in transesophageal defibrillation. Ventricular fibrillation was electrically induced in 12 domestic pigs. Transesophageal defibrillation was performed between two cutaneous patch electrodes and one esophageal electrode. The lowest energy level with successful defibrillation was defined as the DFT. Using four commercially available defibrillators, DFTs were determined for monophasic, truncated exponential biphasic and rectilinear biphasic shock waveforms. DFTs for biphasic transesophageal shocks were significantly lower than for monophasic shocks, reducing DFT to about 50%. There was no significant difference between the three biphasic defibrillators with regard to DFT. The choice of shock waveform can further decrease the already low DFT in transesophageal defibrillation. Similar to transthoracic defibrillation, biphasic shock waveforms yield lower DFTs in transesophageal defibrillation compared to monophasic shocks. The use of different biphasic waveforms does not seem to have a major effect on DFT in transesophageal defibrillation.

Introduction: Atrial fibrosis has been shown to concur with the persistence of atrial fibrillation (AF) and is only incompletely reversible, thus counteracting attempts to restore and maintain sinus rhythm (SR). Besides the angiotensin system, the matrix metalloproteinases (MMP) play a major role in the pathogenesis of fibrosis. Thus, the present study investigated changes of the MMP system during the development of human AF. Methods and Results: Right atrial appendages of 146 patients were excised during heart surgery and grouped according to rhythm (SR vs AF) and AF duration. Hydroxyproline as a surrogate for collagen content and morphometrically determined collagen content increased significantly from SR (14.3 ± 7.7%) to chronic permanent AF (CAF) of 6–24 months (21.2 ± 9.2%, P = 0.02), and CAF of > 60 months (25.3 ± 4.7%, P < 0.01). From SR to paroxysmal and chronic persistent AF (CPAF) and to CAF MMP-2 and MMP-9 activity rose, while their mRNA and protein levels were not altered significantly. Plasminogen activator inhibitor (PAI), an inhibitor of a potent activator of many MMPs, was significantly decreased with increasing duration of AF. In parallel, the mRNA levels of the tissue inhibitors of MMPs TIMP-1 and -2 decreased significantly. Conclusion: Human atrial fibrogenesis is enhanced with increasing duration of AF: a longer AF duration is associated with elevated atrial interstitial MMP activity, but decreased PAI and TIMP expression.

Atrial fibrillation (AF), the most common arrhythmia, has a major impact on both patient morbidity and healthcare economics. Hospital admissions due to AF have risen by two-thirds in the last 20 years. This is due mainly to an aging population and an increasing prevalence of chronic heart disease. Strategies for the management of AF include prevention of thromboembolism, rate control and correction of the arrhythmia. Electrical cardioversion as one component of the treatment of AF requires the absence of atrial thrombi. Transesophageal echocardiography is used routinely for exclusion of atrial thrombi prior to cardioversion in many hospitals. This review presents preliminary data on the clinical use of devices for simultaneous transesophageal echocardiography and transesophageal cardioversion.

Background Transesophageal echocardiography (TEE) is routinely used to exclude atrial thrombus prior to cardioversion of atrial fibrillation (AF). Because the TEE probe lies adjacent to the atria, cardioversion using an electrode attached to the TEE probe should allow for immediate low-energy transesophageal cardioversion. Objective The purpose of this study was to evaluate a cardioversion electrode sheath that can be affixed to conventional TEE probes for simultaneous thrombus exclusion and cardioversion of AF. Methods A thin electrode was integrated into a latex or polyurethane sheath covering a conventional TEE probe. TEE thrombus exclusion and biphasic transesophageal cardioversion using a step-up protocol were performed during deep sedation. Esophagoscopy was performed immediately after cardioversion and after 1 week. Results TEE was performed in 27 patients. One patient showed left atrial thrombi. Transesophageal cardioversion was successful in 25 of the remaining 26 patients. Mean atrial cardioversion threshold was 63 ± 48 J. Transesophageal cardioversion restored sinus rhythm in two patients with unsuccessful transthoracic cardioversion. Transesophageal cardioversion in deep sedation was well tolerated. Esophagoscopy revealed slight mucosal damage in three patients at the site of shock application; two of these patients showed signs of gastroesophageal reflux disease. Mucosal damage unrelated to the site of shock delivery was noted in three patients. Conclusion Atrial thrombus exclusion and transesophageal cardioversion of AF via a disposable cardioversion sheath offers the opportunity to perform transesophageal cardioversion and TEE thrombus exclusion during one sedation. It may not be suitable for use in patients with gastroesophageal reflux disease. Transesophageal cardioversion may establish sinus rhythm in selected patients refractory to transthoracic cardioversion.

Autoantibodies have been identified as major predisposing factors for dilated cardiomyopathy (DCM). Patients with DCM show elevated serum levels of vascular endothelial growth factor (VEGF) whose source is unknown. Besides its well-investigated effects on angiogenesis, evidence is present that VEGF signaling is additionally involved in fibroblast proliferation and cardiomyocyte hypertrophy, hence in cardiac remodeling. Whether autoimmune effects in DCM impact cardiac VEGF signaling needs to be elucidated.Five DCM patients were treated by the immunoadsorption (IA) therapy on five consecutive days. The eluents from the IA columns were collected and prepared for cell culture. Cardiomyocytes from neonatal rats (NRCM) were incubated with increasing DCM-immunoglobulin-G (IgG) concentrations for 48 h. Polyclonal IgG (Venimmun N), which was used to restore IgG plasma levels in DCM patients after the IA therapy was additionally used for control cell culture purposes.Elevated serum levels of VEGF decreased significantly after IA (Serum VEGF (ng/ml); DCM pre-IA: 45 ± 9.1 vs. DCM post-IA: 29 ± 6.7; P 0.05). In cell culture, pretreatment of NRCM by DCM-IgG induced VEGF expression in a time and dose dependent manner. Biologically active VEGF that was secreted by NRCM significantly increased BNP mRNA levels in control cardiomyocytes and induced cell-proliferation of cultured cardiac fibroblast (Fibroblast proliferation; NRCM medium/HC-IgG: 1 ± 0.0 vs. NRCM medium/DCM-IgG 100 ng/ml: 5.6 ± 0.9; P 0.05).The present study extends the knowledge about the possible link between autoimmune signaling in DCM and VEGF induction. Whether this observation plays a considerable role in cardiac remodeling during DCM development needs to be further elucidated.

BioMed research international 2015, 810797 (2015). doi:10.1155/2015/810797, Published by Hindawi, New York [u.a.]

Background Pre-interventional three-dimensional (3D) reconstruction of the heart by CT or MRI provides important information on cardiac anatomy for electrophysiological interventions. However, updates of 3D-imaging modalities with high soft-tissue contrast are not available during ablation procedures. Objective We describe the development and first clinical testing of a close to real-time visualization of cardiac anatomy by intracardiac echocardiography (ICE). Methods An electronic phased-array 5–10 MHz ICE-catheter (AcuNav ™ /Siemens/64 elements) was inserted via a straightened femoral vein sheath (12F) and placed in the right atrium in 5 pigs. A custom-made prototype stepper motor allowed automatic rotation around the longitudinal axis from 90° to 360° in 2–5° steps. For every plane 2D images of a complete cardiac cycle were acquired, triggered by respiration and ECG. The ultrasound images were digitized and 3D-reconstruction was performed by a prototype software. After experimental validation the system was tested in 6 patients during electrophysiological studies. Results From a single location in the right atrium, 3D-acquisition and reconstruction of both atria and ventricles with good image quality were achieved within 3–5 minutes. Doppler-mode facilitated identification of the great vessels including the pulmonary veins and their entry into the heart. 3D-visualization of ablation catheters was also possible in all patients and pigs. Conclusion Semi-automated 3D intracardiac echocardiography from a single site inside the right atrium provides the electrophysiologist with a detailed image of both atria and ventricles with repeated updates of the cardiac anatomy.

Because of the proximity of the esophagus to the heart, transesophageal defibrillation might increase defibrillation success. We assessed the defibrillation threshold (DFT) of transesophageal defibrillation compared with standard transthoracic defibrillation.Defibrillation success and DFTs were determined in 22 female pigs with high (68+/-4 kg, n=12) or low body weight (39+/-1 kg, n=10). After induction of ventricular fibrillation, biphasic shocks were delivered between two cutaneous patch electrodes (sternal and apical position) or between an esophageal and two cutaneous patch electrodes in a sternal and apical position. The esophageal electrode was integrated into a latex sheath covering a standard transesophageal echocardiography probe.In 5 of 12 pigs with high body weight, external defibrillation failed despite 3 consecutive 200-J shocks, whereas subsequent transesophageal defibrillation was successful with the first shock. In the remaining 7 pigs, a more than 50% reduction in DFT was obtained with transesophageal defibrillation compared with standard biphasic external defibrillation (67+/-27 vs 164+/-23 J, P.001). Pigs with lower body weight were successfully defibrillated by both transthoracic and transesophageal shocks. The DFT in pigs with low body weight was significantly lower using transesophageal defibrillation compared with transthoracic shocks (65+/-15 vs 99+/-38 J, P.05).In this animal model, nonresponders to standard external defibrillation could successfully be defibrillated via an esophageal-cutaneous electrode configuration. Overall, an almost 50% DFT reduction was achieved by transesophageal defibrillation. Transesophageal defibrillation may provide an additional tool for terminating VF, which is refractory to external defibrillation, eg, in patients with very high body weight.

Bisher konnte das vegetative kardiale Nervensystem im Wesentlichen nur durch medikamentose Katecholamingabe, β-Rezeptoren-Blockade oder Atropingabe therapeutisch beeinflusst werden. Das intrinsische kardiale Nervensystem stellt ein neuronales Netzwerk dar, das eine dynamische Anpassung der Herzfunktion an verschiedene physiologische und pathophysiologische Einflusse ermoglicht. Inzwischen gelingen eine Identifizierung und Lokalisierung dieser Nervenfasern mittels perkutaner Katheterstimulation. Dies ermoglicht die gezielte Stimulation parasympathischer Nervenfasern, die Sinus- oder AV-Knoten innnervieren, wodurch z. B. die atrioventrikulare Uberleitung bei tachykardem Vorhofflimmern gebremst werden kann. Eine Stimulation sympathischer linksventrikularer Nervenfasern erhoht selektiv die kardiale Inotropie. Auch eine Stimulation parasympathischer Neurone mittels chronischer Verweilelektroden gelingt inzwischen. Daruber hinaus kann durch die gezielte Ausschaltung vegetativer Nerven mittels Katheterverodung Einfluss auf das atriale Substrat von Vorhofflimmern genommen werden. Die perkutane elektrische Stimulation und Ablation kardialer vegetativer Nervenfasern bieten daher die Moglichkeit, dynamisch in die Regulation von kardialer Kontraktion, Perfusion und Erregungsausbreitung einzugreifen.

Objectives This study was designed to develop a technique to selectively increase the sympathetic tone to the heart by cardiac sympathetic nerve stimulation (SNS). Background Access to the cardiac sympathetic neurons may allow modulating the adrenergic tone of the heart while avoiding systemic side effects. Methods Cardiac sympathetic nerves course within neural sleeves along the subclavian artery. Because of this proximity, transvascular SNS was attempted with electrode catheters inside the subclavian artery in 16 pigs. Results Right/left (R-/L-) SNS (20 Hz) during ventricular pacing at 200/min evoked a >100% increase of left ventricular systolic pressure (baseline: 51 ± 1 mm Hg; L-SNS: 118 ± 26 mm Hg; R-SNS: 116 ± 33 mm Hg; p Conclusions The neural adrenergic tone to the heart can be selectively increased by catheter stimulation of cardiac efferent sympathetic nerves.

Cardiac resynchronization therapy (CRT) is a new therapeutic option in patients with heart failure and ventricular conduction delay. We compared the long-term performance of left ventricular (LV) pacing via the coronary venous (CV) approach and a limited lateral thoracotomy (LLT). Data from 81 patients (age 65 +/- 12 years; 52 men, New York Heart Association class 3.0 +/- 0.4, ejection fraction 24 +/- 6%) were retrospectively analyzed for 1 year after implantation of a CRT system. Twenty-five patients received LLT leads and 56 patients received CV leads. Postoperative hospitalization was shorter after CV lead implantation (8 +/- 4 vs 12 +/- 5 days, p

Episodes of hospitalization for heart failure patients are frequent and are often accompanied by fluid accumulations. The change of the body impedance, measured by bioimpendace spectroscopy, is an indicator of the water content. The hypothesis was that it is possible to detect edema from the impedance data. First, a finite integration technique was applied to test the feasibility and allowed a theoretical analysis of current flows through the body. Based on the results of the simulations, a clinical study was designed and conducted. The segmental impedances of 25 patients suffering from heart failure were monitored over their recompensation process. The mean age of the patients was 73.8 and their mean body mass index was 28.6. From these raw data the model parameters from the Cole model were deduced by an automatic fitting algorithm. These model data were used to classify the edema status of the patient. The baseline values of the regression lines of the extra- and intracellular resistance from the transthoracic measurement and the baseline value of the regression line of the extracellular resistance from the foot-to-foot measurement were identified as important parameters for the detection of peripheral edema. The rate of change of the imaginary impedance at the characteristic frequency and the mean intracellular resistance from the foot-to-foot measurement were identified as important parameters for the detection of pulmonary edema. To classify the data, two decision trees were considered: One should detect pulmonary edema (n(pulmonary) = 13, n(none) = 12) and the other peripheral edema (n(peripheral) = 12, n(none) = 13). Peripheral edema could be detected with a sensitivity of 100% and a specificity of 90%. The detection of pulmonary edema showed a sensitivity of 92.31% and a specificity of 100%. The leave-one-out cross-validation-error for the peripheral edema detection was 12% and 8% for the detection of pulmonary edema. This enables the application of BIS as an early warning system for cardiac decompensation with the potential to optimize patient care.

Journal of cardiothoracic surgery 9, 114 (2014). doi:10.1186/1749-8090-9-114, Published by BioMed Central, London