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Background In cardiac arrest, computerized analysis of the ventricular fibrillation (VF) waveform provides prognostic information, while its diagnostic potential is subject of study. Animal studies suggest that VF morphology is affected by prior myocardial infarction (MI), and even more by acute MI. This experimental in‐human study reports on the discriminative value of VF waveform analysis to identify a prior MI. Outcomes may provide support for in‐field studies on acute MI. Methods and Results We conducted a prospective registry of implantable cardioverter defibrillator recipients with defibrillation testing (2010–2014). From 12‐lead surface ECG VF recordings, we calculated 10 VF waveform characteristics. First, we studied detection of prior MI with lead II, using one key VF characteristic (amplitude spectrum area [AMSA]). Subsequently, we constructed diagnostic machine learning models: model A, lead II, all VF characteristics; model B, 12‐lead, AMSA only; and model C, 12‐lead, all VF characteristics. Prior MI was present in 58% (119/206) of patients. The approach using the AMSA of lead II demonstrated a C‐statistic of 0.61 (95% CI, 0.54–0.68). Model A performance was not significantly better: 0.66 (95% CI, 0.59–0.73), P =0.09 versus AMSA lead II. Model B yielded a higher C‐statistic: 0.75 (95% CI, 0.68–0.81), P P =0.66 versus model B. Conclusions This proof‐of‐concept study provides the first in‐human evidence that MI detection seems feasible using VF waveform analysis. Information from multiple ECG leads rather than from multiple VF characteristics may improve diagnostic accuracy. These results require additional experimental studies and may serve as pilot data for in‐field smart defibrillator studies, to try and identify acute MI in the earliest stages of cardiac arrest.

Contains fulltext : 190474.pdf (Publisher’s version ) (Open Access) Sudden cardiac arrest or death (SCA/SCD) in athletes has a low event rate. Pre-participation or eligibility screening is a widely accepted method of primary prevention of SCA/SCD in athletes. Most European countries and international sports governing bodies perform ECG-inclusive screening. However, implementation of a resting 12-lead ECG in pre-participation or eligibility cardiac screening is still a topic of debate. Recently, the 'International recommendations for electrocardiographic interpretation in athletes' was published in three leading international medical journals. These international ECG criteria are based on studies with detailed information on resting 12-lead ECG of Caucasian and Afro-Caribbean athletes or on consensus in case evidence was lacking. Normal, borderline and abnormal ECG findings in young athletes (age 12-35 years) are clearly described and illustrated to assist the screening physician in interpreting ECGs of athletes correctly.In this 'point of view paper' we will discuss whether these new ECG criteria actually help prevent SCA/SCD in athletes.

Background Studies on international registries report improved outcomes after in- and out-of-hospital cardiac arrest over the last decade. The 2015 resuscitation guidelines incorporate initiatives derived from both guidelines 2005 and 2010, respectively. Purpose In order to assess the impact of these respective updates, we aim to provide the most comprehensive quantitative summary of comparative studies that specifically focused on outcomes before and after guideline updates. Methods PubMed, Web-of-Science, Embase and The Cochrane Libraries were searched for studies that compared clinical outcomes of patients resuscitated in the period before and after introduction of guidelines 2010 and 2005, respectively. Results For studies on guidelines 2010 vs. 2005 (n=6; 1,002 patients), the pooled estimate did not indicate a difference [OR 1.29 (95% CI 0.74–2.25) p=0.372] in return of spontaneous circulation (ROSC). For survival to discharge a significant benefit [OR 1.70 (1.01–2.84) p=0.045] was observed for patients resuscitated according to guideline 2010. As for guidelines 2005 vs. 2000 (n=23; 40,859 patients), the pooled estimates for ROSC, survival to admission, to discharge and favourable neurologic outcome consistently indicated benefit for guideline 2005 [OR 1.21 (1.04–1.42) p=0.014; OR 1.34 (1.09–1.65) p=0.005; OR 1.46 (1.25–1.70) p Conclusions This comprehensive meta-analysis quantifies the positive impact of resuscitation guideline updates on outcomes and supports the current way of guideline development. While there is robust evidence for improved overall outcomes after guidelines 2005, the 2010 guideline benefit was restricted to improved survival to discharge. In terms of quality control, our findings call for continued initiatives to monitor outcomes after guideline updates. Acknowledgement/Funding None

Updates of resuscitation guidelines have limited high-level supporting evidence. Moreover, the overall effect of such bundled practice changes depends not only on the impact of the individual interventions but also on their interplay and swift functioning of the entire chain of survival. Therefore, real-world data monitoring is essential. We performed a meta-analysis of comparative studies on outcomes before and after successive guideline updates. On January 16, 2019, we searched for comparative studies (PubMed, Web-of-Science, Embase, and the Cochrane Libraries) reporting outcomes before and after resuscitation guidelines 2005, 2010, and 2015. We followed PRISMA, Cochrane, and Moose-recommendations. Studies on outcomes during the 2005 versus 2000 guideline period (n = 23; 40,859 patients) reported significantly higher ROSC (odds ratio [OR] 1.21 [1.04 to 1.42], p = 0.014), survival to admission (OR 1.34 [1.09 to 1.65], p = 0.005), survival to discharge (OR 1.46 [1.25 to 1.70], p0.001), and favorable neurologic outcome (OR 1.35 [1.01 to 1.81], p = 0.040). Studies on outcomes during the 2010 versus 2005 guideline period (n = 11; 1,048,112 patients) indicated no difference in ROSC (OR 1.25 [95% confidence interval 0.95 to 1.63], p = 0.11), whereas survival to discharge improved significantly (OR 1.30 [1.17 to 1.45], p0.001). Only 2 studies reported on neurologic outcomes, both showing improved outcome after the 2010 guideline update. No data on the 2015 guidelines were available. This meta-analysis on real-world data of1 million patients demonstrates improved outcomes after the 2005 and 2010 resuscitation guideline updates, and a lack of data on the 2015 guideline. In conclusion, although limited in terms of causality, this study suggests that the sum of all efforts to improve outcomes, including updated CPR guidelines, contributed to increased survival after cardiac arrest.

Contains fulltext : 165971.pdf (Publisher’s version ) (Open Access) A noncontact mapping system (EnSite) was used for electroanatomical mapping of the bladder simultaneously with pressure flow study in three women with lower urinary tract symptoms. We selected the periods of obvious detrusor activity. Data were processed to remove baseline drift, and an envelope of electrovesicography (EVG) data was created. The correlation coefficient for the correlation between between the EVG envelope and the detrusor pressure (Pdet) was calculated. Bladder geometry was successfully created in all 3 patients. Simultaneous recording of EVG and pressure flow data was successful in 1 patient. Scatter plots were made of the highest correlation coefficient, showing a positive correlation between the Pdet and the envelope, and negative correlation between abdominal pressure (Pabd) and the envelope. Minimal electrical activity could be observed. Significant weak to moderate correlation coefficients were found for the correlations between Pdet and EVG and between Pabd and EVG.

Introduction In view of the shift from routine toward no or selective defibrillation testing, optimization of the current risk stratification for inadequate defibrillation safety margins (DSMs) could improve individualized testing decisions. Given the pathophysiological differences in myocardial substrate between ischemic and nonischemic heart disease (IHD/non-IHD) and the accompanying differences in clinical characteristics, we studied inadequate DSMs and their predictors in relation to the underlying etiology. Methods and results Cohort of routine defibrillation tests (n = 785) after first implantable cardioverter defibrillator (ICD)-implantations at the Radboud UMC (2005-2014). A defibrillation threshold >25 J was regarded as an inadequate DSM. In total, 4.3% of patients had an inadequate DSM; in IHD 2.5% versus 7.3% in non-IHD (P = 0.002). We identified a group of non-IHD patients at high risk (13-42% inadequate DSM); the remainder of the cohort (>70%) had a risk of only 2% (C-statistic entire cohort 0.74; C-statistic non-IHD 0.82). This was based upon two identified interaction terms: (1) non-IHD and age (aOR 0.94 [95% CI 0.91-0.97]); (2) non-IHD and the indexed left ventricular (LV) internal diastolic diameter (aOR 3.50 [95% CI 2.10-5.82]). Conclusion The present study on risk stratification for an inadequate DSM not only confirms the importance of making a distinction between IHD and non-IHD, but also shows that risk factors in an entire cohort (LV dilatation, age) may only apply to a subgroup (non-IHD). Appreciation of this concept could favorably affect current risk stratification. If confirmed, our approach may be used to optimize individualized testing decisions in an upcoming era of non-routine testing.

Contains fulltext : 182938.pdf (Publisher’s version ) (Open Access) BACKGROUND: Despite a promising association between VF waveform characteristics and prognosis after resuscitation, studies with VF-guided treatment have so far not improved outcomes. While driven by the idea that the VF waveform reflects arrest duration, increasing evidence suggests that pre-existent disease-related changes of the myocardium affect ECG-characteristics of VF as well. In this context, we studied the impact of the left ventricular (LV) diameter and mass. METHODS: Cohort of 193 ICD-patients with defibrillation testing at the Radboudumc (2010-2014). Surface ECG-recordings (leads I,II,aVF,V1,V3,V6) were analysed to study amplitude and frequency characteristics of the induced VF. Both for LV diameter and mass, patients were categorised in two groups, using echocardiographic data (ASE-guidelines). RESULTS: In all ECG-leads, dominant and median frequencies were significantly lower in patients with (n=40) than in patients without (n=151) an increased LV diameter. The mean amplitude and amplitude spectrum area (AMSA) did not differ. In contrast, we observed no differences in frequency characteristics in relation to the LV mass, whereas mean amplitude (I,aVF,V3) and AMSA (I,V3) were significantly higher in patients with (n=57) than in patients without (n=120) an increased LV mass. CONCLUSIONS: Frequency characteristics of VF were consistently lower in case of an increased LV diameter. Whereas LV mass does not affect the frequency of the VF waveform, amplitudes seem higher with increasing mass. These findings add to the current knowledge of factors that modulate VF characteristics of the surface ECG and provide insight into factors which may be accounted for in future studies on VF-guided resuscitative interventions.

Neutral lipid storage disease with myopathy (NLSDM) is a rare but severe genetic disorder characterized by excessive lipid accumulation in tissues including skin, bone marrow, heart, liver, and muscles. Clinically, NLSDM patients present with severe dilated cardiomyopathy, skeletal muscle myopathy, and insulin resistance.1 NLSDM is caused by a defect in the PNPLA2 gene encoding the enzyme adipose triglyceride lipase (ATGL),2 which catalyzes the breakdown of triglycerides in multiple tissues and is the rate-limiting step of lipolysis. Although heterozygous carriers and homozygous patients both present with similar clinical symptoms, the severity of these symptoms in homozygous patients is more dramatic, leading to premature death attributed to dilated cardiomyopathy in some patients.1,2 To date, the only available treatment is strict dietary guidelines and is focused on treating the comorbidities rather than targeting the primary defect. To investigate cardiac lipotoxicity in NLSDM, ATGL-deficient mice have been investigated. Just like NLSDM patients, ATGL-deficient mice are also characterized by excessive lipid storage in skeletal muscle, liver, and heart, and they develop cardiomyopathy at a young age, resulting in premature death.3 Interestingly, we reported recently that a lack of ATGL resulted in a diminished cardiac peroxisome proliferator-activated receptor (PPAR) activity and mitochondrial function, suggesting that lipolysis-derived fatty acids or fatty acid byproducts serve as transcriptional activators of PPARs.4 Subsequently, pharmacological treatment of ATGL-deficient mice with PPAR agonists completely reversed the mitochondrial defects, restored cardiac function, and prevented premature death. These promising findings inspired us to investigate whether PPAR agonist treatment in patients and carriers of a PNPLA2 gene defect could also have beneficial effects. Although NSLDM is a very rare disease, we had the opportunity to study 2 sisters with PNPLA2 gene mutations. Patient 1 is a 37-year-old woman with a body mass index of 21.4 kg/m2. …

Contains fulltext : 169229.pdf (Publisher’s version ) (Closed access) BACKGROUND: Of the proposed algorithms that provide guidance for in-field termination of resuscitation (TOR) decisions, the guidelines for cardiopulmonary resuscitation (CPR) refer to the basic and advanced life support (ALS)-TOR rules. To assess the potential consequences of implementation of the ALS-TOR rule, we performed a case-by-case evaluation of our in-field termination decisions and assessed the corresponding recommendations of the ALS-TOR rule. METHODS: Cohort of non-traumatic out-of-hospital cardiac arrest (OHCA)-patients who were resuscitated by the ALS-practising emergency medical service (EMS) in the Nijmegen area (2008-2011). The ALS-TOR rule recommends termination in case all following criteria are met: unwitnessed arrest, no bystander CPR, no shock delivery, no return of spontaneous circulation (ROSC). RESULTS: Of the 598 cases reviewed, resuscitative efforts were terminated in the field in 46% and 15% survived to discharge. The ALS-TOR rule would have recommended in-field termination in only 6% of patients, due to high percentages of witnessed arrests (73%) and bystander CPR (54%). In current practice, absence of ROSC was the most important determinant of termination [aOR 35.6 (95% CI 18.3-69.3)]. Weaker associations were found for: unwitnessed and non-public arrests, non-shockable initial rhythms and longer EMS-response times. CONCLUSION: While designed to optimise hospital transportations, application of the ALS-TOR rule would almost double our hospital transportation rate to over 90% of OHCA-cases due to the favourable arrest circumstances in our region. Prior to implementation of the ALS-TOR rule, local evaluation of the potential consequences for the efficiency of triage is to be recommended and initiatives to improve field-triage for ALS-based EMS-systems are eagerly awaited. 6 p.

The ideal energy source and strategy for repeat ablation procedures of atrial fibrillation (AF) has to be established. Data on redo procedures using cryoballoon technique are limited. We report long-term follow-up on cryoballoon redo procedures after an initial successful cryoballoon ablation. The

Contains fulltext : 97916.pdf (Publisher’s version ) (Open Access) BACKGROUND: Antithrombotic management in atrial fibrillation (AF) is currently based on clinical characteristics, despite evidence of potential fine-tuning with transoesophageal echocardiography (TEE). This open, randomised, multicentre study addresses the hypothesis that a comprehensive strategy of TEE-based aspirin treatment in AF patients is feasible and safe. METHODS: Between 2005 and 2009, ten large hospitals in the Netherlands enrolled AF patients with a moderate risk of stroke. Patients without thrombogenic TEE characteristics were randomised to aspirin or vitamin K antagonists (VKA). The primary objective is to show that TEE-based aspirin treatment is safe compared with VKA therapy. The secondary objective tests feasibility of TEE as a tool to detect echocardiographic features of high stroke risk. This report compares randomised to non-randomised patients and describes the feasibility of a TEE-based approach. RESULTS: In total, 310 patients were included. Sixty-nine patients were not randomised because of non-visualisation (n = 6) or TEE risk factors (n = 63). Compared with non-randomised patients, randomised patients (n = 241) were younger (65 +/- 11 vs. 69 +/- 9 years, p = 0.004), had less coronary artery disease (9 vs. 20%, p = 0.018), previous TIA (1.7 vs. 7.2%, p = 0.029), AF during TEE (25 vs. 54%, p < 0.001), mitral incompetence (55 vs. 70%, p = 0.038), VKA use (69 vs. 82%, p = 0.032), had a lower mean CHADS(2) score (1.2 +/- 0.6 vs. 1.6 +/- 1.0, p = 0.004), and left ventricular ejection fraction (59 +/- 8 vs. 56 +/- 8%, p = 0.016). CONCLUSIONS: This study shows that a TEE-based approach for fine-tuning stroke risk in AF patients with a moderate risk for stroke is feasible. Follow-up data will address the safety of this TEE-based approach.

Item does not contain fulltext Safe sports participation involves protecting athletes from injury and life-threatening situations. Preparticipation cardiovascular screening (PPS) in athletes is intended to prevent exercise-related sudden cardiac death by medical management of athletes at risk, which may include disqualification from sports participation. The screening physician relies on current guidelines and expert recommendations for management and decision-making. There is concern about false-positive screening results and wrongly grounding an athlete. Similarly, there is a concern about false-negative screening results and athletes participating with potentially lethal disorders. Who is legally responsible if an athlete suddenly dies after a proper PPS resulting in low risk? Several consensus documents based on expert opinion describe only a few lines on legal responsibilities in eligibility screening and disqualification decision-making in athletes. This article discusses legal responsibilities and concerns in eligibility decision-making for physicians.

Contains fulltext : 170930.pdf (Publisher’s version ) (Closed access) STUDY OBJECTIVE: Mechanical chest compression devices have been developed to facilitate continuous delivery of high-quality cardiopulmonary resuscitation (CPR). Despite promising hemodynamic data, evidence on clinical outcomes remains inconclusive. With the completion of 3 randomized controlled trials, we conduct a meta-analysis on the effect of in-field mechanical versus manual CPR on clinical outcomes after out-of-hospital cardiac arrest. METHODS: With a systematic search (PubMed, Web of Science, EMBASE, and the Cochrane Libraries), we identified all eligible studies (randomized controlled trials and nonrandomized studies) that compared a CPR strategy including an automated mechanical chest compression device with a strategy of manual CPR only. Outcome variables were survival to hospital admission, survival to discharge, and favorable neurologic outcome. RESULTS: Twenty studies (n=21,363) were analyzed: 5 randomized controlled trials and 15 nonrandomized studies, pooled separately. For survival to admission, the pooled estimate of the randomized controlled trials did not indicate a difference (odds ratio 0.94; 95% confidence interval 0.84 to 1.05; P=.24) between mechanical and manual CPR. In contrast, meta-analysis of nonrandomized studies demonstrated a benefit in favor of mechanical CPR (odds ratio 1.42; 95% confidence interval 1.21 to 1.67; P

Background Ventricular fibrillation (VF) waveform characteristics are associated with cardiac arrest duration and defibrillation success. Recent animal studies found that VF characteristics and shock success also depend on the presence of myocardial infarction (MI). In patients, VF induction after implantable cardioverter defibrillator (ICD) implantation offers a unique setting to study early VF characteristics: we studied the relation with cardiac disease – either presence or absence of a previous MI – and with shock success. Methods Retrospective cohort study of ICD-patients who underwent defibrillation testing, 117 (63%) with and 69 (37%) without a previous MI. Intracardiac recordings of induced VF were analysed using Fourier analysis. Results In previous MI-patients, the fundamental frequency and organisation index of the VF signal were significantly lower as compared with patients without a previous MI: 4.9Hz±0.6 vs. 5.2Hz±0.6 ( p =0.005) and 56%±10 vs. 60%±9 ( p =0.001), respectively. The median frequency was not different ( p =0.25). We found no association between VF characteristics and ICD shock success. Conclusions In analogy with observations in animals, we found that a history of a previous MI was associated with slower and less organised VF. In our cohort of ICD-patients, early VF waveform characteristics were not associated with shock outcomes. Further study is warranted to determine to what extent VF characteristics are influenced by the underlying aetiology on the one hand, and time delay on the other. These findings could improve insight into the potential value of VF analysis to guide shock delivery.

Contains fulltext : 59318.pdf (Publisher’s version ) (Closed access) OBJECTIVES: The purpose of this study was to characterize the morphology of fibrillation electrograms in patients in order to provide insight into the underlying electropathologic substrate of atrial fibrillation (AF). BACKGROUND: Electrograms recorded during AF show a high degree of spatiotemporal variation. METHODS: AF was induced by rapid atrial pacing in 25 patients undergoing cardiac surgery. A unipolar mapping array of 244 electrodes was positioned on the free wall of the right atrium to record multiple epicardial fibrillation electrograms. Local anisotropy in conduction and epicardial wavefront curvature during AF were determined by fitting the best quadratic surface on the activation times of rectangular areas of 3 x 3 electrodes. RESULTS: During AF, unipolar epicardial electrograms revealed a clear predominance of S waves. The average RS difference during type I and II AF was -0.15 +/- 0.08 and -0.22 +/- 0.08. During type III AF, the predominance of S waves was less prominent (-0.07 +/- 0.05; P < .005). In all types of AF, the degree of anisotropy in conduction was remarkably low (anisotropy ratio: 1.24 +/- 0.09), and no clear directional effect on the relative amplitude of R and S waves was found. There was a weak relationship between local curvature of wavefronts and RS difference (r = 0.23; P < .01). Computer simulations showed that the negative RS difference could result from transmural activation in an epicardial to endocardial direction. CONCLUSIONS: The clear predominance of S waves in epicardial fibrillation electrograms is not due to anisotropy and can only be partly explained by a high curvature of fibrillation waves. Predominant epicardial to endocardial activation seems to be important in producing rS electrograms on the epicardium. This finding provides indirect evidence that the thin epicardial layer of atrial myocardium plays an important role in propagation of fibrillation waves.

Background In this feasibility study, early results are presented of our first series of patients with microwave ablation for atrial fibrillation (AF) on the beating heart. Methods From June 2001 until December 2001, a total of 24 patients underwent beating-heart epicardial ablation for AF. With a microwave antenna, the left and right pulmonary veins were isolated and connected to each other followed by amputation of the left atrial appendage. Subsequently, patients underwent either off-pump coronary artery bypass graft or valve surgery on pump. The mean age of the patients was 67.4 ± 6 years. Three patients experienced paroxysmal atrial fibrillation and all others chronic AF. Mean left atrial diameter was 5.4 ± 0.6 cm, and mean ablation time was 13 min. Results All procedures but one were completed successfully on the beating heart. All patients were in sinus rhythm after the procedure. A total of 15 patients experienced periods with postoperative AF during hospital stay; 9 of these patients were discharged with AF. All patients received either sotalol or amiodarone. At latest follow-up (3 to 9 months), 20 of 23 patients were in sinus rhythm. Conclusions With microwave ablation, electrical isolation of the pulmonary veins can be achieved epicardially without cardiopulmonary bypass support.

A catheter-based method of mapping left ventricular electromechanical regional function may be used to optimize application of local myocardial therapies by demarcating zones of ischemia or infarction. We thus performed a detailed comparison between electromechanical parameters and segmental function as assessed by echocardiography in 10 patients (3 with normal ventricles and 7 with old infarcts). Using a 16-segment model, unipolar voltage and local shortening were significantly and independently related to echo score by multivariate analysis, having a concordance with echo score of 73% for shortening and 79% for voltage. Area under ROC curves, expressing the ability to differentiate normal from abnormal segments, had values of 0.75 and 0.81 for local shortening and unipolar voltage, respectively. In conclusion, automatic assessment of regional ventricular function can be achieved independently by electrical and mechanical parameters, compared with echocardiography, permitting an integrated approach to the evaluation of ventricular function and aiding localization of catheter-based therapies.

Background —Accurate mapping of the site of origin and activation sequence of a cardiac arrhythmia is essential for a successful catheter ablation procedure. To achieve this, precise and reproducible catheter manipulation is mandatory. The aim of this study was (1) to assess the accuracy of a new nonfluoroscopic mapping system in humans and (2) to report the first result of endocardial activation mapping with this system during sinus rhythm and several types of supraventricular and ventricular tachycardias. Methods and Results —Fifteen patients were studied. Accuracy measurements were performed in 5 of them (patients 5, 6, 7, 8, and 14). The distances between two subsequent catheter positions in the inferior caval vein as determined by the nonfluoroscopic mapping system were compared with measurements made with calipers by four independent investigators using identification marks on the catheter shaft. The difference between these two methods was 0.95±0.8 mm. In 15 patients, activation of the right atrium and/or the right or left ventricle was recorded during sinus rhythm. Three-dimensional activation maps were constructed in patients with atrial and ventricular tachycardias and Wolff-Parkinson-White syndrome. Conclusions —With this new nonfluoroscopic mapping technique, accurate positioning of the catheter tip is possible. A three-dimensional activation map can be reconstructed during sinus rhythm and during supraventricular and ventricular tachycardias of different compartments of the heart.

Electrode Length for Atrial Defibrillation. Introduction: Catheter-based electrodes have been used previously to terminate episodes of atrial fibrillation in animals and man. Typically, these electrodes span 6 to 7 cm, and lowest energy requirements are achieved when these electrodes are positioned in the distal coronary sinus and in the right atrium. The purpose of this study was to evaluate the use of longer electrode lengths for atrial defibrillation. Methods and Results: In 15 patients, two decapolar catheters were inserted, one into the distal coronary sinus and one in the right atrium. To provide longer electrodes lengths, a third catheter was inserted and alternated positioned in the right atrium or coronary sinus. A 6-cm electrode span was obtained by using the distal 8 rings on the coronary sinus catheter or 8 consecutive electrodes on the right atrial catheter and increased from 6 to 11 cm by connecting consecutive, nonoverlapping rings of the third catheter with the 10 rings of the initial right atrial or coronary sinus catheter. Atrial defibrillation thresholds were determined twice, in a randomized order, in each patient for each of the three combinations of electrode lengths. All 15 patients could he successfully converted to sinus rhythm without complications; however, one patient could be converted reproducibly with only 2 of the 3 electrode combinations. Mean thresholds were 306 ± 102 V, 5.9 ± 4.0 J for the 6 cm/6 cm electrode length combination with an impedance of 72 ± 18 ω. For the electrode combination using the 11-cm electrode in the right atrium, the defibrillation threshold was 296 ± 107 V, 5.8 ± 3.9 J with an impedance of 61 ± 17 ω and was 294 ± 91 V, 5.6 ± 3.6 J with an impedance of 55 ± 11 ω for the 11-cm electrode in the coronary sinus. There were no significant differences in defibrillation voltage or energy (P > 0.05) associated with the longer electrode lengths; however, the longer electrode lengths did significantly lower shock impedance (P < 0.05). Conclusion: The use of longer electrodes, when using the right atrium to coronary sinus shock vector, does not lower the defibrillation requirements for restoration of sinus rhythm.

Objectives—To examine the effect of isoprenaline on slow and fast pathway properties and tachycardia initiation. Design—Consecutive patients, prospective study. Setting—Referral centre for cardiology, academic hospital. Patients—24 patients suffering from common type atrioventricular nodal re-entrant tachycardia (AVNRT). Interventions—Programmed electrical stimulation and radiofrequency catheter ablation of the slow pathway. Measurements and main results—AVNRT was induced before and after the administration of isoprenaline in nine patients (group 1), before isoprenaline only in five (group 2), and after isoprenaline only in 10 (group 3). The anterograde effective refractory period of the fast pathway was prolonged significantly during isoprenaline administration in group 1 (405 (31) v 335 (34) ms, p

Sudden death can be the first manifestation of the Wolff-Parkinson-White (WPW) syndrome. The underlying mechanism being atrial fibrillation with a very high ventricular rate, because of a short anterograde refractory period of the accessory atrioventricular pathway (AP), deteriorating into ventricular fibrillation. Information on the anterograde refractory period of the AP is therefore important to recognize asymptomatic people with the WPW ECG at risk for dying suddenly. Several noninvasive tests are available to identify the low risk patient. Decision making when to interrupt the AP in asymptomatic WPW patients not at low risk requires an invasive study to document the electrophysiological properties of the AP and to determine its exact location.

We performed radiofrequency catheter ablation of idiopathic ventricular tachycardia in six children. In four, the ventricular tachycardia originated in the left ventricle, in two it originated in the right ventricular outflow tract. In 5/6 (83%) the RF procedure was successful; there were no complications.

Monomorphic VT in HCM. Introduction: Incessant monomorphic ventricular tachycardia (VT) with a right bundle branch block morphology and a northwest axis is a rare arrhythmic complication in a patient with hypertrophic cardiomyopathy and apical left ventricular aneurysm. Methods and Results: The origin of this VT was localized using the following criteria: the presence of entrainment without fusion, equal internals from the stimulus to the beginning of the QRS complex and from the electrogram to the QRS complex during VT, and the first postpacing interval identical to the tachycardia cycle length. Radiofrequency energy applied to the septoapical part of the apical left ventricular aneurysm terminated the tachycardia within 2 seconds. Conclusion: Using criteria to guide radiofrequency (RF) ablation of VT in patients with coronary artery disease, an incessant monomorphic VT in a patient with hypertrophic cardiomyopathy was successfully ablated.

Background During atrial fibrillation (AF), the atrium is activated by multiple wavelets that continuously change in size and direction. The aim of this study was to correlate the temporal variation in AF electrogram configuration with the varying spatial patterns of activation. Methods and Results In a group of 25 Wolff-Parkinson-White patients undergoing cardiac surgery, the free wall of the right atrium was mapped (244 points) during electrically induced AF. The unipolar electrograms recorded during 4 seconds of AF were classified into four categories: (1) single deflections, (2) short-double potentials, (3) long-double potentials, and (4) fragmented potentials. The proportion of these four types of electrograms during AF was as follows: singles, 77±12%; short-doubles, 7±3%; long-doubles, 10±7%; and fragmented, 6±4%. Electrogram morphology was an indicator for rapid uniform conduction (single potentials; positive predictive value [PPV] of 0.96), collision (short-double potentials; PPV of 0.33), conduction block (long-double potentials; PPV of 0.84), and pivoting points or slow conduction (fragmented potentials; PPV of 0.87). In type I, II, and III AF, the proportion of long-double potentials was 4±2%, 12±3%, and 18±7% ( P P Conclusions The morphology of single unipolar electrograms during AF reflects the occurrence of various specific patterns of conduction. This might be used to differentiate between different types of AF and to identify regions with structural conduction disturbances involved in perpetuation of chronic AF.

Contains fulltext : 125460.pdf (Publisher’s version ) (Open Access) PURPOSE: This study was conducted to investigate the degree of fibrosis in atrial appendages of patients with and without atrial fibrillation (AF) undergoing cardiac surgery. In addition, we hypothesized that areas of atrial fibrosis can be identified by electrogram fractionation and low voltage for potential ablation therapy. METHODS: Interstitial fibrosis from right (RAA) and/or left atrial appendages (LAA) was studied in patients with sinus rhythm (SR, n = 8), paroxysmal (n = 21), and persistent AF (n = 20) undergoing coronary artery bypass and/or aortic or mitral valve surgery. Atrial fibrosis quantification was performed with Masson trichrome staining. Intraoperative bipolar epicardial electrophysiological measurements were performed to correlate fibrosis to electrogram fractionation, voltage, and AF cycle length. RESULTS: The average degree of fibrosis was 11.2 +/- 7.2 % in the LAA and 22.8 +/- 7.6 % in the RAA (p < 0.001). Fibrosis was not significantly higher in paroxysmal AF patients compared to SR subjects (18.2 +/- 8.7 versus 20.7 +/- 5.3 %). Persistent AF patients had a higher degree of LAA and RAA fibrosis compared to paroxysmal AF patients (LAA 14.6 +/- 8.7 versus 8.6 +/- 4.7 %, p = 0.02, and RAA 28.2 +/- 7.9 versus 18.2 +/- 8.7 %, respectively, p = 0.04). The left atrial end diastolic volume index was higher in persistent AF patients compared to SR controls (38.3 +/- 16.4 and 28 +/- 11 ml/m(2), respectively, p = 0.04). No correlation between atrial fibrosis and electrogram fractionation or voltage was found. CONCLUSION: Patients with structural heart disease undergoing cardiac surgery have more fibrosis in the RAA than in the LAA. Furthermore, RAA fibrosis is increased in persistent AF but not paroxysmal AF patients compared to control subjects. Electrogram fractionation and low voltage did not provide accurate identification of the fibrotic substrate.

OBJECTIVE--To examine the value of programmed electrical stimulation of the heart in predicting sudden death in patients receiving amiodarone to treat ventricular tachyarrhythmias after myocardial infarction. DESIGN--Consecutive patients; retrospective study. SETTING--Referral centre for cardiology, academic hospital. PATIENTS--106 patients with ventricular tachycardia (n = 77) or ventricular fibrillation (n = 29) late after myocardial infarction. INTERVENTIONS--Programmed electrical stimulation was performed while on amiodarone treatment for at least one month. MEASUREMENTS AND MAIN RESULTS--In 80/106 patients either ventricular fibrillation (n = 15) or sustained monomorphic ventricular tachycardia (n = 65) was induced. After a mean follow up of 50 (SD 40) months (1-144), 11 patients died suddenly and two used their implantable cardioverter debfibrillator. By multivariate analysis two predictors for sudden death were found: (1) inducibility of ventricular fibrillation under amiodarone treatment (P << 0.001), and (2) a left ventricular ejection fraction of < 40% (P < 0.05). The survival rate at one, two, three, and five years was 70%, 62%, 62%, and 40% respectively for patients in whom ventricular fibrillation was induced, and 98%, 96%, 94%, 94% for patients with induced sustained monomorphic ventricular tachycardia. Where there was no sustained arrhythmia, five year survival was 100%. CONCLUSIONS--In patients receiving amiodarone because of life threatening ventricular arrhythmias after myocardial infarction, inducibility of ventricular fibrillation, but not of sustained monomorphic ventricular tachycardia, indicates a high risk of sudden death.

Item does not contain fulltext AIMS: To investigate the behaviour of the implantable cardioverter defibrillator (ICD) function during actual radiotherapy sessions. METHODS AND RESULTS: Fifteen patients with an ICD underwent 17 radiation treatments for cancer [cumulative dose to the tumour was between 16 Gray (Gy) and 70 Gy; photon beams with maximum energies between 6 megaelectronvolt (MeV) and 18 MeV were employed]. During every session, the ICD was programmed to a monitoring mode to prevent inappropriate therapy delivery. Afterwards, the ICDs were interrogated to ensure proper function. Calculated radiation dose at the ICD site was /=10 MeV, and boron-10 which is present in the integrated circuit.

Item does not contain fulltext AIMS: Cryoballoon (CB) ablation has proven very effective in achieving pulmonary vein isolation (PVI). The Achieve catheter (AC) is a novel inner lumen catheter designed to be used in conjunction with the CB, which serves the double purpose of a guidewire and a mapping catheter. We aimed to evaluate the feasibility of CB ablation in conjunction with the novel AC, in terms of PVI and safety in a series of patients affected by drug resistant paroxysmal atrial fibrillation (AF). METHODS AND RESULTS: Seventy patients (49 male) affected by paroxysmal AF were assigned to CB PVI using the AC as a mapping catheter. Patients underwent loop-Holter monitoring 1, 3 and 6 months after ablation. Isolation occurred in 98% of PVs with the CB-AC association without having switching to a regular guidewire. Pulmonary vein isolation could be documented by real-time (RT) recordings in 47% (132) of veins. Time to isolation was significantly longer in PVs exhibiting early left atrium-PV reconnection if compared with veins with sustained isolation (117 +/- 25 s vs. 59 +/- 25 s; P< 0,005). No serious complications occurred; four transient phrenic nerve palsies occurred all resolving completely before the end of the procedure. CONCLUSION: Cryoballoon ablation in conjunction with the novel AC is feasible, safe, and most importantly affords PVI in nearly all veins without having to switch to a regular guidewire. However, RT recordings could be documented in only 47% of pulmonary veins. 01 juli 2012

Item does not contain fulltext AIMS: Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice. Nowadays, catheter-based ablative approaches are mainly reserved for drug-refractory patients. However, the value of an ablative therapy as a first-line alternative remains elusive. The aim of our study was to analyse the acute procedural success and clinical outcome of patients with lone paroxysmal AF undergoing cryoballoon ablation (CBA) as first-line treatment. METHODS AND RESULTS: Eighteen individuals (mean age 44 +/- 9 years, range 23-61 years, 15 males) with lone paroxysmal AF preferring a catheter-based treatment to drug treatment as first-line therapy were consecutively enrolled in our study. Mean left atrial size was 39 +/- 4 mm and mean left ventricular ejection fraction 58 +/- 3%. After a mean of 2.4 CBA (range 2-4) applications pulmonary vein (PV) isolation could be demonstrated in 70 (97%) PVs. Additional lesions with a focal ablation catheter were needed to isolate one right inferior pulmonary vein and one left superior pulmonary vein in two different patients. At the end of the procedure, all (100%) PVs were isolated. After a 2-month blanking period, 16 patients (89%) were free of symptomatic AF recurrence at a mean follow-up of 14 +/- 9 months and without antiarrhythmic drugs (AADs). CONCLUSION: Cryoballoon ablation in patients with lone paroxysmal AF yields a high acute efficacy rate with a great chance of being free of symptomatic AF recurrence without antiarrhythmic drugs on a mid-term follow-up period, when offered as a first-line treatment. 01 februari 2012

OBJECTIVE--To evaluate characteristics of patients and accessory pathways as well as additional technical factors involved in the reappearance of accessory pathway conduction after successful ablation. DESIGN--Analysis of recurrences after radiofrequency ablation. SETTING--163 consecutive patients with 167 accessory pathways. SUBJECTS--97 men and 66 women with a mean (SD) age of 36 (14) range (11 to 75) years. RESULTS--After a mean (SD) follow up of 14 (7) range (2 to 27) months, conduction recurred in 13 out of 167 (7.8%) accessory pathways. The initial manifestation of recurrence was circus movement tachycardia in 7 patients and reappearance of delta waves on a 12 lead electrocardiogram in 6 patients. The interval to the return of accessory pathway conduction ranged from 3 hours to 90 days. Age, sex, presence of multiple accessory pathways, criteria to determine the target ablation site, number and duration of radiofrequency applications, and cumulative energy did not significantly differ between the groups with recurrence and without. Recurrence was less common with concealed accessory pathways (2/44) than with overt accessory pathways (11/110). The difference was not significant. The only variable to influence the recurrences in this study group was the location of the accessory pathway. Reappearance of conduction through right sided accessory pathways occurred significantly more often than through left sided ones (8/40 v 5/114, P = 0.01). CONCLUSION--After radiofrequency ablation the recurrence rate of accessory pathways is low and there are no predictors of the risk of reappearance of conduction apart from the right sided location of the accessory pathway.

The acute anatomic and valvular consequences of radiofrequency catheter ablation of accessory pathways were evaluated in 62 patients by means of serial echocardiographic examinations. Semiquantitative assessment of valvular incompetence and classification into one of four grades according to the width and the extension of the jet from the valvular orifice were carried out. Segmental wall motion abnormalities were evaluated semiquantitatively with four grades of severity (normal, hypokinesia, akinesia, or dyskinesia). New echocardiographic abnormalities were observed in five patients. One thrombus on the ventricular aspect of the mitral valve, three hemodynamically insignificant pericardial effusions, and one increase in severity of tricuspid incompetence were found 1 day after radiofrequency catheter ablation. We conclude that echocardiographic changes after radiofrequency ablation of accessory pathways are rare and of minor significance. These findings confirm the safety of the procedure.

A 78-year-old man presents with dizziness for 3 days. This lasts for 30 s to 1 min; he does not feel palpitations and has no other cardiac symptoms. Nine years ago, he was analysed for chest pain; exercise testing and echocardiography were normal. His further medical history reveals depression and hemi-colectomy because of colon carcinoma. Current medication consists of aspirin, lisinopril, simvastatin, lithium carbonate, nortrilen, pantozol, alprazolam and movicolon. Physical examination revealed a slow regular pulse of 40 beats/min with a blood pressure of 110/60 mmHg, and investigation of heart and lungs was within normal limits. The ECG on admission is shown in Fig. 1. Laboratory examination showed a normal blood level of lithium and nortrilen. The echocardiography showed normal left ventricular function with a mild aortic stenosis. Fig. 1 ECG on admission (25 mm/s, 10 mm/mV) What is your interpretation of the ECG? ■ Answer You will find the answer elsewhere in this issue.

OBJECTIVE--To assess the efficacy of radiofrequency ablation for reentrant tachyarrhythmias in children and young adults. SETTING--A tertiary cardiac referral centre. PATIENTS AND INTERVENTIONS--Over a 16 month period 22 patients aged less than 20 years (median age 16.5 years) underwent 26 radiofrequency ablation procedures for atrioventricular reentry tachycardia through an accessory pathway. The results of radiofrequency ablation were compared with those in a group of 16 patients (median age 14 years) who had had surgical ablation for atrioventricular reentry tachycardia over a preceding six year period. RESULTS--Ablation of an accessory atrioventricular pathway was accomplished for 18 (76%) of 25 pathways in 16 (73%) of 22 patients. There were no procedure-related complications. Surgery was eventually curative in 15/16 patients (94%). However, three patients required a second open heart surgical procedure because tachyarrhythmia recurred. There were no surgical deaths. Failures for radiofrequency ablation were related to accessory pathway location, and were greater for right free wall and posteroseptal pathways (success rate of 50% and 57% respectively). Recurrence after surgery was also associated with pathways in these locations. CONCLUSIONS--Transcatheter radiofrequency current ablation was safe and achieved a cure with less patient morbidity and improved cost efficiency. It is an attractive alternative to long-term drug therapy or surgery in older children and adolescents. A higher success rate may be expected with increased experience.

We studied the relationship between wall motion abnormalities determined by echocardiography and the signal-averaged electrocardiogram in 82 consecutive patients during the acute phase of a first myocardial infarction. An abnormal signal-averaged electrocardiogram was defined as the presence of two of the following criteria: a QRS durationor = 114 ms, a root mean square voltage (RMS) of the last 40 msor = 25 microV and an amplitude signal lower than 40 microV lastingor = 39 ms. The left ventricle was divided into 13 segments and the contraction pattern divided into akinesia alone (including dyskinesia) (group A), hypokinesia alone (group B) and both hypokinesia and akinesia (group C). An abnormal signal-averaged electrocardiogram was found in 14/82 patients (17%) and was correlated with the persistence of occlusion of the infarct-related vessel (32% vs 9%, P0.02). In patients with a patent vessel, the incidence of an abnormal signal-averaged electrocardiogram was 14% in group A, 9% in group B and 0% in group C (NS). In patients with an occluded vessel an abnormal signal-averaged electrocardiogram was found in 10% of group A patients, in 36% in group B patients and in 75% of group C patients (P = 0.05). Our study suggests that the presence of hypokinetic areas during the acute phase of a first myocardial infarction and an abnormal signal-averaged electrocardiogram indicate an occluded infarct-related vessel.

Background— During persistent atrial fibrillation (AF), waves with a focal spread of activation are frequently observed. The origin of these waves and their relevance for the persistence of AF are unknown. Methods and Results— In 24 patients with longstanding persistent AF and structural heart disease, high-density mapping of the right and left atria was performed during cardiac surgery. In a reference group of 25 patients, AF was induced by rapid pacing. For data analysis, a mapping algorithm was developed that separated the fibrillatory process into its individual wavelets and identified waves with a focal origin. During persistent AF, the incidence of focal fibrillation waves in the right atrium was almost 4-fold higher than during acute AF (median, 0.46 versus 0.12 per cycle per 1 cm 2 (25th to 75th percentile, 0.40 to 0.77 and 0.01 to 0.27; P 3) happened in only 0.8. The coupling interval was not more than 11 ms shorter than the average AF cycle length ( P =0.04), and they were not preceded by a long interval. Unipolar electrograms at the site of origin showed small but clear R waves. These data favor epicardial breakthrough rather than a cellular focal mechanism as the underlying mechanism. Often, conduction from a site of epicardial breakthrough was blocked in 1 or more directions. This generated separate multiple wave fronts propagating in different directions over the epicardium. Conclusions— Focal fibrillation waves are due to epicardial breakthrough of waves propagating in deeper layers of the atrial wall. In patients with longstanding AF, the frequency of epicardial breakthroughs was 4 times higher than during acute AF. Because they provide a constant source of independent fibrillation waves originating over the entire epicardial surface, they offer an adequate explanation for the high persistence of AF in patients with structural heart disease.

Background— The electropathological substrate of persistent atrial fibrillation (AF) in humans is largely unknown. The aim of this study was to compare the spatiotemporal characteristics of the fibrillatory process in patients with normal sinus rhythm and long-standing persistent AF. Methods and Results— During cardiac surgery, epicardial mapping (244 electrodes) of the right atrium (RA), the left lateral wall (LA), and the posterior left atrium (PV) was performed in 24 patients with long-standing persistent AF. Twenty-five patients with normal sinus rhythm, in whom AF was induced by rapid pacing, served as a reference group. A mapping algorithm was developed that separated the complex fibrillation process into its individual elements (wave mapping). Parameters used to characterize the substrate of AF were (1) the total length of interwave conduction block, (2) the number of fibrillation waves, and (3) the ratio of block to collision of fibrillation waves (dissociation index). In 4403 maps of persistent AF, no evidence for the presence of stable foci or rotors was found. Instead, many narrow wavelets propagated simultaneously through the atrial wall. The lateral boundaries of these waves were formed by lines of interwave conduction block, predominantly oriented parallel to the atrial musculature. Lines of block were not fixed but continuously changed on a beat-to-beat basis. In patients with persistent AF, the total length of block in the RA was more than 6-fold higher than during acute AF (median, 21.1 versus 3.4 mm/cm 2 ; P 2 ). The number of fibrillation waves during persistent AF was 4.5/cm 2 compared with 2.3 during acute AF, and the dissociation index was 7.3 versus 1.5 ( P Conclusions— Electric dissociation of neighboring atrial muscle bundles is a key element in the development of the substrate of human AF. The degree of the pathological changes can be measured on an individual basis by electrophysiological parameters in the spatial domain.

Long-term ECG recordings are of great value in the diagnosis and management of patients with cardiac arrhythmias. Information from programmed stimulation studies and intracardiac recordings has markedly improved the diagnostic abilities of the person examining the long-term ECG recording. This article discusses how knowledge from intracardiac electrophysiologic studies has resulted in much better recognition of the type and mechanisms of a supraventricular arrhythmia on the Holter record.

Incidence and timing of recurrences of sustained ventricular tachycardia (VT) or sudden death were studied in 206 patients who survived their first episode of ventricular fibrillation (VF; n = 52) or sustained VT (n = 154) after myocardial infarction. All patients were treated with (empirically selected) antiarrhythmic drugs; 49% received amiodarone. After a mean follow-up of 36 months, 64 patients (41%) in the VT group and 10 (19%) in the VF group had nonfatal VT recurrences. Sudden death occurred in 22 (14%) and 9 (17%) patients in the VT and VF groups, respectively. Incidence of sudden death had 2 peaks at approximately 3 and 12 months. Nonfatal VT recurrences were more frequent (most often occurring in first 6 months) in the VT than in the VF group. Sudden death occurred during the following 3 years in only 10% of patients who survived 1 year. There was a much higher incidence of sudden death in patients with left ventricular ejection fraction (LVEF) less than or equal to 40% than in those with LVEF greater than 40% (28 of 65 vs 3 of 141; p less than 0.0001), but no relation between LVEF and nonfatal VT recurrences.

Radiofrequency Ablation of Multiple Accessory Pathways. A 19-year-old patient is described having three accessory atrioventricular pathways. All three pathways were ablated using radiofrequency current in a single electrophysiologic investigation. (J Cardiovasc Electrophysiol, Vol. 3, pp. 141–149, April 1992)

Any physician treating cardiac arrhythmias should be aware of a possible worsening of the arrhythmia (so-called arrhythmogenesis) after the start of antiarrhythmic drug treatment. To facilitate the recognition of that complication the type and possible mechanisms of arrhythmogenesis are reviewed. Recognition also requires an understanding of (a) the time of appearance of arrhythmogenic effects after different drugs, (b) the value of non-invasive and invasive tests, and (c) the profile of the patient most likely to develop this problem. Guidelines are given to reduce the incidence of the arrhythmogenic effects of antiarrhythmic drugs and a plea is made that the physician should be always on the alert for this complication.

The Metrix™ Atrioverter Expanded Indication Trial evaluates the safety and efficacy of an implantable atrial defibrillator in patients with symptomatic, recurrent and drug refractory atrial fibrillation who also have structural heart disease. In this ongoing multicenter study, all patients are anticoagulated and concomitant antiarrhythmic drug treatment is left to the preference of the physician. Holter monitoring is performed prior to enrollment in the study. Spontaneous episodes of atrial fibrillation (AF) are treated under physician observation and when patients are ambulatory, the device is programmed in a monitoring mode. The atrial defibrillation threshold is measured at implantation and at 3, 6 and 12 months thereafter. The performance of the AF detection and R-wave synchronization algorithm is assessed at implantation, at regular follow-up intervals, and each time the patient visits the hospital for treatment of a spontaneous episode of AF. An echocardiogram is performed prior to implantation, at 3 and 6 month follow-up and for patients with an implanted heart valve, after 20 and 50 atrial defibrillation shocks have been delivered. The study started on October 1997 and will end after the last patient enrolled completes his/her six-month post-implantation follow-up, unless a safety issue arises. As of September 1998, 6 patients (2 patients with tachycardia induced cardiomyopathy, 1 patient with a mitral valve prosthesis, 2 patients with hypertrophic cardiomyopathy and 1 patient with congenital heart disease) have been enrolled in the study. Over 350 shocks have been delivered for atrial defibrillation testing or termination of spontaneous AF episodes. There have been no reported cases of ventricular proarrhythmia or inaccurately synchronized shocks and no complications of device therapy in this population.

A 23-year-old male top-level soccer player was referred to our clinic because of recent onset of lightheadedness during training, without loss of postural tone, which lasted for a few seconds. His family history was negative for sudden cardiac death and other known cardiovascular diseases.

This is a 49-year-old male marathon runner with family history positive for coronary artery disease in both parents, and atrial fibrillation in the father.

Contains fulltext : 80026.pdf (Publisher’s version ) (Closed access) An 8-year-old girl who was recently diagnosed as having anaplastic large-cell lymphoma presented with atrial tachycardia and dilated cardiomyopathy, which is a contraindication for further treatment with cardio-toxic chemotherapy. After starting digoxin therapy, the dilated cardiomyopathy resolved. Repeated episodes of atrial tachycardia in this case were not caused by any common disorder but were due to mechanical stimulation by a central venous catheter. Central venous catheters are known to cause mainly ventricular arrhythmias. However, atrial tachycardia is a rare manifestation of arrhythmia due to mechanical stimulation of the heart by a central venous catheter, with potentially important cardiovascular consequences.