Distinctive characteristics of His bundle potentials in patients with atrioventricular nodal reentrant tachycardia.

BACKGROUND: His bundle (HB) potentials vary in amplitude and duration in patients with and without slow pathways. The aim of this study was to determine the characteristics of HB potentials and to elucidate whether they can provide clues for identification of slow pathway (SP). METHODS: The present research prospectively studied the electrophysiological findings of 162 patients with symptomatic atrioventricular nodal reentrant tachycardia (AVNRT) due to slow-fast or fast-slow type and atrioventricular reentrant tachycardia (AVRT). Maximal HB potential (HBmax, HB with the highest amplitude) among HB cloud was recorded in both groups. For AVNRT patients, the following were measured: (1) AH interval at the "jump" during programmed atrial stimulation (A2H2, taken as a reflection of SP conduction time); (2) Distance from HBmax to the successful SP ablation site (HBmax-ABL) and from HBmax to the ostium of coronary sinus (HBmax-CSO). RESULTS: HBmax was 0.29 ± 0.10 mV in AVNRT patients, whereas it was 0.17 ± 0.05 mV in AVRT group (p < 0.0001). Likewise, the HBmax duration was 22 ± 5 ms in AVNRT group and 16 ± 3 ms in AVRT group (p < 0.0001). The area under the receiver operating characteristic curve of HBmax amplitude in AVNRT patients was 0.86 and the optimal HBmax cut-off to predict AVNRT was ≥ 0.22 mV with a sensitivity of 0.78 and specificity of 0.84. HBmax-CSO was positively correlated with HBmax-ABL, and HBmax-ABL was positively correlated with A2H2. CONCLUSIONS: HBmax amplitudes were higher and durations longer in patients with AVNRT, as compared to those with AVRT. Moreover, the distance between HBmax and successful ablation site was positively correlated with the SP conduction time and with the distance from HBmax to the CSO.

Medical therapy with flecainide and propafenone in atrial fibrillation: Long-term clinical experience in the tertiary care setting.

BACKGROUND: Flecainide and propafenone are Class Ic antiarrhythmic drugs that block the cardiac fast inwards Na+ current and are used for rhythm control in patients with atrial fibrillation (AF). However, data on long-term clinical efficacy and safety of these drugs in a real-world setting are scarce. METHODS: Patients with AF who received chronic flecainide or propafenone therapy were retrospectively studied from the database of a tertiary care center. The primary outcome of the study was clinical efficacy of Class Ic antiarrhythmics, which was assessed based on the improvement of arrhythmia-related symptoms at the time of last follow-up. RESULTS: Among the 361 patients (261 males, 72.3%) with a mean age of 56 ± 12 years, 287 (79.5%) were using long-term flecainide, and 74 (20.5%) patients propafenone. The majority of the patients had paroxysmal AF (n = 331, 91.7%) and had an atrioventricular-nodal blocking co-medication (n = 287, 79.5%). A total of 117 (32%) patients discontinued therapy after a median of 210 days (interquartile range 62-855 days). Clinical efficacy was observed in 188 (52%) patients. The most common reason for therapy discontinuation was adverse drug effects, particularly proarrhythmic effects (48% for flecainide and 33% for propafenone). Patients who did not clinically benefit from Class Ic antiarrhythmics more often underwent pulmonary vein isolation (p = 0.02). CONCLUSIONS: Long-term therapy with Class Ic antiarrhythmics showed clinical efficacy in approximately half of the patients with paroxysmal or persistent AF. However, these drugs were also associated with a relatively high rate of adverse events, and in particular proarrhythmic effects, which often resulted in therapy discontinuation rendering appropriate patient selection and therapy surveillance essential.

Wearable Cardioverter-Defibrillator-Measured Step Count for the Surveillance of Physical Fitness during Cardiac Rehabilitation.

BACKGROUND: The wearable cardioverter-defibrillator (WCD) has a built-in accelerometer, which allows tracking of patients' physical activity by remote monitoring. It is unclear whether WCD-measured physical activity, step count, and heart rate correlate with established tools for the assessment of cardiopulmonary fitness such as the 6-min walk test (6MWT). OBJECTIVE: To correlate measurements of patient physical activity through the WCD with a supervised 6MWT during in-patient cardiac rehabilitation (CR) and to allow their use as surrogate parameters of cardiopulmonary fitness in an out-patient setting. METHODS: Consecutive patients with a history of WCD use treated at our center and an in-patient CR following an index hospitalization were included. Baseline characteristics, measurements of WCD accelerometer (median daily step count, median daily activity level), median daily heart rate, and clinically supervised 6MWT at admission and discharge of CR were obtained. RESULTS: Forty-one patients with a mean age of 55.5 (±11.5) years were included. Thirty-five patients (85.4%) were male and 28 patients (68%) had a primary prophylactic WCD-indication. The most common underlying heart diseases were ischemic heart disease (24 patients 58.6%) and dilated cardiomyopathy (13 patients, 31.7%). Median CR duration was 20 (IQR 19.75-26.25) days. 6MWT distance increased from a mean of 329 m (±107) to 470 m (±116) during CR (p < 0.0001). The median daily step count and activity level increased significantly, from 5542 steps (IQR 3718-7055) to 8778 (IQR 6229-12,920, p < 0.0001) and median 117 × 106 (IQR 96 × 106-142 × 106) threshold value exceedance (TVE) to 146 × 106 TVE (IQR 110 × 106-169 × 106, p < 0.0001), respectively. The median heart rate was 74.9 bpm (IQR 65.8-84.5) and 70.2 (IQR 64.1-77.3, p = 0.09) at admission and discharge, respectively. Of all three parameters, median daily step count showed the best correlation to the results of the 6MWT at admission and discharge (r = 0.32, p = 0.04 and 0.37, p = 0.02, respectively). CONCLUSIONS: Remote monitoring of median daily step count as assessed by the WCD's accelerometer showed positive correlation with the 6MWT and could serve as a surrogate for cardiopulmonary exercise capacity. Assessment of daily step count and activity level measured remotely by the WCD could help to tailor optimal exercise instruction for patients not attending CR.

Recurrent syncope after a finger injury and induced monomorphic ventricular tachycardia: Really Brugada syndrome?

Brugada syndrome is an arrhythmogenic disease with often fatal outcome in otherwise healthy and young individuals. Anamnesis and ECG are cornerstones in a syncope workup. In our case, a 27-year-old male presented to the emergency department due to recurrent syncope. Repeated 12­lead-ECGs revealed a type 2 Brugada pattern. A positive drug challenge suggested a Brugada syndrome and electrophysiological testing reproducibly induced monomorphic ventricular tachycardia. Consequently, an ICD was implanted for secondary prevention. On 2-year follow-up, the patient remained free from other arrhythmic events or ICD interventions.

Use of the wearable cardioverter-defibrillator - the Swiss experience.

INTRODUCTION: Sudden cardiac death caused by malignant arrhythmia can be prevented by the use of defibrillators. Although the wearable cardioverter defibrillator (WCD) can prevent such an event, its role in clinical practice is ill defined. We investigated the use of the WCD in Switzerland with emphasis on prescription rate, therapy adherence and treatment rate. MATERIALS AND METHODS: The Swiss WCD Registry is a retrospective observational registry including patients using a WCD. Patients were included from the first WCD use in Switzerland until February 2018. Baseline characteristics and data on WCD usage were examined for the total study population, and separately for each hospital. RESULTS: From 1 December 2011 to 18 February 2018, a total of 456 patients (67.1% of all WCDs prescribed in Switzerland and 81.1% of all prescribed in the participating hospitals) were included in the registry. Up to 2017 there was a yearly increase in the number of prescribed WCDs to a maximum of 271 prescriptions per year. The mean age of patients was 57 years (± 14), 81 (17.8%) were female and mean left ventricular ejection fraction (EF) was 32% (± 13). The most common indications for WCD use were new-onset ischaemic cardiomyopathy (ICM) with EF ≤35% (206 patients, 45.2%), new-onset nonischaemic cardiomyopathy (NICM) with EF ≤35% (115 patients, 25.2%), unknown arrhythmic risk (83 patients, 18.2%), bridging to implantable cardioverter-defibrillator implantation or heart transplant (37 patients, 8.1%) and congenital/inherited heart disease (15 patients, 3.3%). Median wear duration was 58 days (interquartile range [IQR] 31–94) with a median average daily wear time of 22.6 hours (IQR 20–23.2). Seventeen appropriate therapies from the WCD were delivered in the whole population (treatment rate: 3.7%) to a total of 12 patients (2.6% of all patients). The most common underlying heart disease in patients with a treatment was ICM (13/17, 76.5%). There were no inappropriate treatments. CONCLUSION: The use of WCDs has increased in Switzerland over the years for a variety of indications. There is high therapy adherence to the WCD, and a treatment rate comparable to previously published registry data.  .

Outcomes during and after the use of the wearable cardioverter-defibrillator in a tertiary-care and a regional hospital in Switzerland.

INTRODUCTION: The wearable cardioverter-defibrillator (WCD) has established itself in treatment of potentially life-threatening ventricular arrhythmias, when implantation of an implantable cardioverter-defibrillator (ICD) is not warranted. Careful patient selection for this therapy is crucial, but unfortunately very little information from randomised controlled trials is available to guide clinical decision-making. Consequently, data from real-world patient registries play a more important role in this context. MATERIALS AND METHODS: A retrospective observational study was conducted at the University Hospital of Zurich and the GZO Regional Healthcare Centre in Wetzikon. Clinical databases were screened for patients with a history of WCD use from the time of its approval in Switzerland in July 2014 until February 2018. Baseline characteristics, WCD data and outcome data, with an emphasis on ICD implantation and ICD therapies, were collected and analysed. RESULTS: Two-hundred and seven patients were included in the primary analysis. Eighty-six percent were male and the mean age was 58 ± 13 years. The underlying heart disease was ischaemic cardiomyopathy (ICM), non-ischaemic cardiomyopathy (NICM) and congenital/inherited heart diseases in 60, 35 and 5%, respectively. The most common indication for WCD use was heart failure with an ejection fraction (EF) <35% due to ICM or NICM (43 and 27%, respectively). Three of the 207 patients received an appropriate shock over a median WCD wear-time of 62 days (interquartile range [IQR] 35–95). No inappropriate shocks were registered. Median average daily wear-time was 22.6 hours (IQR 19.9–23.2) and was significantly shorter for patients for whom WCD discontinuation was due to comfort issues (17 patients, p = 0.003). After the end of WCD therapy, 48% were implanted with an ICD. In those receiving an ICD, the rate of appropriate ICD therapies (either shock or antitachycardia pacing) was 8% during a median follow-up of 110 days (IQR 23–421). CONCLUSION: The WCD is safe and effective in terminating malignant ventricular arrhythmias. A substantial subgroup of patients, however, discontinued WCD use prematurely because of comfort issues. This subset of patients deserves further attention in clinical practice to ensure therapy adherence.  .

Arrhythmic episodes in patients implanted with a cardioverter-defibrillator - results from the Prospective Study on Predictive Quality with Preferencing PainFree ATP therapies (4P).

BACKGROUND: Little is known about the ICD performance using enhanced detection algorithms in unselected, non-trial patients. Performance of recent generation ICD equipped with SmartShock™ technology (SST) for detection and conversion of ventricular tachyarrhythmias (VTA) was investigated. METHODS: 4P was a prospective, multicenter, observational study conducted in 10 Swiss implanting centers. Patients with a Class I indication according to international guidelines were included and received an ICD with SST. ICD discrimination capability was assessed by evaluating SST performance; therapy efficacy was assessed by rate of VTA conversions by ATP and by rescue shocks. RESULTS: Overall, 196 patients were included in the analysis with a mean duration of follow-up of 27.7 months (452 patient-years of observation). Patient-specific rather than recommended programming was preferred. Device-detected episodes were frequent (5147 episodes in 146 patients, 74.5%). In 44 patients (22.4%), 1274 episodes were categorized as VTA; only 215 episodes were symptomatic. ATP was the first-line therapy and highly effective (99.9% success rate at the episode level, 100.0% at the patient level). Rescue shocks were rare (66 episodes in 28 patients); 7 shocks in 5 patients (2.6%) were inappropriate. Death and hospitalization rates were low. CONCLUSIONS: In a cohort of non-trial, unselected ICD patients, VTA episodes were frequent. The 4P results confirm the robustness of VTA detection by SST and the effectiveness of ATP treatment, hence limiting overall ICD shock burden.

Extended Use of the Wearable Cardioverter-Defibrillator: Which Patients Are Most Likely to Benefit?

BACKGROUND: Wearable cardioverter-defibrillators (WCD, LifeVest, ZOLL) can protect from sudden cardiac death bridging a vulnerable period until a decision on implantable cardioverter-defibrillator (ICD) implantation can be reached. WCD is commonly used for 3 months or less. It is unknown, which patients use WCD longer and which patients are most likely to benefit from it. HYPOTHESIS: Extended use of WCD is reasonable in selected cases based on underlying heart disease and overall patient risk profile. METHODS: We conducted a systematic and comprehensive research of all published clinical studies on PubMed reporting on the use of the WCD. Only original articles reporting on wear times and time to appropriate shocks were included in our analysis. RESULTS: The search resulted in 127 publications. 14 parameters were reported necessary for inclusion in our analysis. Median wear times ranged from 16 to 394 days. The median wear time was especially long for patients suffering from nonischemic cardiomyopathy (NICM) (range: 50-71 days) and specifically peripartum cardiomyopathy (PPCM) (120 days) and for heart transplant candidates. There was a large variation of appropriate shocks according to indication for WCD use. In contrast to NICM in general, the number of appropriate shocks was particularly high in patients with PPCM (0 in 254 patients and 5 in 49 patients, respectively). The median and maximal time periods to the first appropriate shock were longest in patients with PPCM (median time to the first appropriate shock: 68 days). CONCLUSIONS: Prolonged use of WCD is not uncommon in available literature. Patients suffering from NICM and specifically PPCM seem most likely to have longer therapy duration with WCD with success. Careful patient selection for prolonged use may decrease the need for ICD implantation in the future; however, prospective data are needed to confirm this hypothesis.

Corrigendum to "Falls and Fractures in the Elderly with Sinus Node Disease: The Impact of Pacemaker Implantation".

[This corrects the article DOI: 10.1155/2012/498102.].

Long-term incidence of inappropriate shocks in patients with implantable cardioverter defibrillators in clinical practice-an underestimated complication?

BACKGROUND: Implantable cardioverter defibrillators (ICD) are life-saving device therapy, and patients often carry devices for decades with interim pulse generator exchanges. Inappropriate shocks are associated with impaired quality of life and increased mortality, but available data on their incidence and etiology outside of clinical trials is limited and usually restricted to the lifespan of a singular device. We hypothesized that the incidence in clinical practice is underestimated and aimed this study to retrospectively assess the long-term incidence and etiology of inappropriate shocks in a real-world cohort of patients with multiple ICDs over a long follow-up period. METHODS: Patients with ICDs implanted between 1998 and 2012 in two Swiss cardiology departments and at least one device exchange in the same department thereafter were included in this cohort. Retrospective analysis with follow-up until 2016 was conducted to assess incidence and etiology of inappropriate ICD shocks. RESULTS: Two hundred forty-nine ICDs were implanted in 100 patients (mean age: 60.1 ± 11.7; 80% male). Over a mean follow-up time of 11.2 (± 3.6) years, 555 shocks occurred in 55 patients. One hundred twenty-three (22%) shocks in 23 (23%) patients were inappropriate. Supraventricular arrhythmia and oversensing were the most frequent causes of inappropriate shock. Patients with younger age or previous supraventricular arrhythmias were at increased risk of inappropriate shocks. Patients with inappropriate shocks during the lifespan of their first ICD were at increased risk for inappropriate shocks in subsequent devices. CONCLUSIONS: Inappropriate shocks are an underestimated and frequent problem in clinical practice with an incidence that may exceed numbers of previously reported clinical trials with shorter follow-up periods. Patients at increased risk for inappropriate shocks need careful evaluation of potential therapeutic optimization strategies including pharmacological treatment, device programming, electrophysiological ablation, device downgrading, and telemonitoring.

"Real world" experience in Cardiac Resynchronization Therapy at a Swiss Tertiary Care Center.

BACKGROUND: Based on a reduction in morbidity and mortality, cardiac resynchronisation therapy (CRT) has evolved as a standard therapy for patients with advanced heart failure. OBJECTIVE: To provide insight into patient demographics, safety, echocardiographic remodelling and long-term follow-up of patients treated with CRT in a "real-world" setting at a Swiss tertiary care centre. METHODS: Patients implanted with a CRT device at the University Heart Centre Zurich between 2000 and 2015 were consecutively enrolled. Initial clinical and echocardiographic therapy response as well as long-term follow-up for mortality (defined as all-cause death, heart transplantation or ventricular assist device implantation) and hospitalisation for heart failure were assessed. RESULTS: A total of 418 patients with a median age of 66 years at the time of CRT implantation (78% male) were enrolled. Serious peri-interventional complications (from the time of implantation up to 14 days thereafter) were rare and included systemic infections in 2.4%, pneumothorax in 3.3% and haematoma requiring revision in 2.2% of cases. Overall, the Kaplan-Meier estimate for 5-year freedom from the composite endpoint (hospitalisation for heart failure or mortality) was 55.8%; the Kaplan-Meier estimate for 5-year freedom from mortality was 64.1%. CRT was associated with a significant symptomatic improvement and left ventricular reverse remodelling. Overall, 3.9% of patients did not respond to cardiac resynchronisation therapy (decline in left ventricular ejection fraction [LVEF] >5%), whereas 35.1% experienced neither a continued decline nor a relevant improvement of LVEF (±5%). In the remaining 61% of patients we observed an improvement in LVEF of more than 5%. Forty percent and 31% of patients were super responders, defined as an absolute LVEF improvement of 10% and by a relative reduction of left ventricular end-diastolic volume index by 20% or more. Super-response to CRT was associated with a significant benefit in terms of survival and rehospitalisation rates. CONCLUSION: Our data are consistent with large multicentre trials and indicate that CRT is similarly effective in a real-world setting in Switzerland.

Reduction of falls and fractures after permanent pacemaker implantation in elderly patients with sinus node dysfunction.

AIMS: Elderly patients with sinus node dysfunction (SND) are at increased risk of falls with possible injuries. However, the incidence of these adverse events and its reduction after permanent pacemaker (PPM) implantation are not known. METHODS AND RESULTS: Eighty-seven patients (mean [SD] age 75.4 [8.3] years, 51% women) with SND and an indication for cardiac pacing were included and were examined by a standardized interview targeting fall history. The incidence and total number of falls, falls with injury, falls requiring treatment, and falls resulting in a fracture were assessed for the time period of 12 months before (retrospectively) and after PPM implantation (prospectively). Furthermore, symptoms such as syncope, dizziness, and dyspnea were evaluated before and after PPM implantation. The implantation of a PPM was associated with a reduced proportion of patients experiencing at least one fall by 71% (from 53 to 15%, P < 0.001) and a reduction of the absolute number of falls by 90% (from 127 to 13, P < 0.001) during the 12 months before vs. after PPM implant. Falls with injury (28 vs. 10%, P = 0.005), falls requiring medical attention (31 vs. 8%, P < 0.001), and falls leading to fracture (8 vs. 0%, P = 0.013) were similarly reduced. Notably, fewer patients had syncope (4 vs. 45%, P < 0.001) and dizziness after PPM implantation (12 vs. 45%, P < 0.001). CONCLUSION: Falls, fall-related injuries, and fall-related fractures are frequent in SND patients. Permanent pacemaker implantation is associated with a significantly reduced risk of these adverse events, although no causal relationship could be established due to the study design.

Lidocaine Enhances Contractile Function of Ischemic Myocardial Regions in Mouse Model of Sustained Myocardial Ischemia.

RATIONALE: Perioperative myocardial ischemia is common in high-risk patients. The use of interventional revascularisation or even thrombolysis is limited in this patient subset due to exceedingly high bleeding risks. Blockade of voltage-gated sodium channels (VGSC) with lidocaine had been suggested to reduce infarct size and cardiomyocyte cell death in ischemia/reperfusion models. However, the impact of lidocaine on cardiac function during sustained ischemia still remains unclear. METHODS: Sustained myocardial ischemia was induced by ligation of the left anterior descending artery in 12-16 weeks old male BALB/c mice. Subcutaneous lidocaine (30 mg/kg) was used to block VGSC. Cardiac function was quantified at baseline and at 72h by conventional and speckle-tracking based echocardiography to allow high-sensitivity in vivo phenotyping. Infarct size and cardiomyocyte cell death were assessed post mortem histologically and indirectly using troponin measurements. RESULTS: Ischemia strongly impaired both, global systolic and diastolic function, which were partially rescued in lidocaine treated in mice. No differences regarding infarct size and cardiomyocyte cell death were observed. Mechanistically, and as shown with speckle-tracking analysis, lidocaine specifically improves residual contractility in the ischemic but not in the remote, non-ischemic myocardium. CONCLUSION: VGSC blockade with lidocaine rescues function of ischemic myocardium as a potential bridging to revascularisation in the setting of perioperative myocardial ischemia.

Electrocardiographic features of disease progression in arrhythmogenic right ventricular cardiomyopathy/dysplasia.

BACKGROUND: Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is considered a progressive cardiomyopathy. However, data on the clinical features of disease progression are limited. The aim of this study was to assess 12-lead surface electrocardiographic (ECG) changes during long-term follow-up, and to compare these findings with echocardiographic data in our large cohort of patients with ARVC/D. METHODS: Baseline and follow-up ECGs of 111 patients from three tertiary care centers in Switzerland were systematically analyzed with digital calipers by two blinded observers, and correlated with findings from transthoracic echocardiography. RESULTS: The median follow-up was 4 years (IQR 1.9-9.2 years). ECG progression was significant for epsilon waves (baseline 14% vs. follow-up 31%, p = 0.01) and QRS duration (111 ms vs. 114 ms, p = 0.04). Six patients with repolarization abnormalities according to the 2010 Task Force Criteria at baseline did not display these criteria at follow-up, whereas in all patients with epsilon waves at baseline these depolarization abnormalities also remained at follow-up. T wave inversions in inferior leads were common (36% of patients at baseline), and were significantly associated with major repolarization abnormalities (p = 0.02), extensive echocardiographic right ventricular involvement (p = 0.04), T wave inversions in lateral precordial leads (p = 0.05), and definite ARVC/D (p = 0.05). CONCLUSIONS: Our data supports the concept that ARVC/D is generally progressive, which can be detected by 12-lead surface ECG. Repolarization abnormalities may disappear during the course of the disease. Furthermore, the presence of T wave inversions in inferior leads is common in ARVC/D.

Clinical role of atrial arrhythmias in patients with arrhythmogenic right ventricular dysplasia.

BACKGROUND: The clinical role of atrial fibrillation/atrial flutter (AF-AFl) and variables predicting these arrhythmias are not well defined in patients with arrhythmogenic right ventricular dysplasia (ARVD). We hypothesized that transthoracic echocardiography (TTE) and 12-lead electrocardiography (ECG) would be helpful in predicting AF-AFl in these patients. METHODS AND RESULTS: ECGs and TTEs of 90 patients diagnosed with definite or borderline ARVD (2010 Task Force Criteria) were analyzed. Data were compared in (1) patients with AF-AFl and (2) all other patients. A total of 18 (20%) patients experienced AF-AFl during a median follow-up of 5.8 years (interquartile range 2.0-10.4). Kaplan-Meier analysis revealed reduced times to AF-AFl among patients with echocardiographic RV fractional area change <27% (P<0.001), left atrial diameter ≥24.4 mm/m(2)(parasternal long-axis, P=0.001), and right atrial short-axis diameter ≥22.1 mm/m(2)(apical 4-chamber view, P=0.05). From all ECG variables, P mitrale conferred the highest hazard ratio (3.37, 95% confidence interval 0.92-12.36, P=0.067). Five patients with AF-AFl experienced inappropriate implantable cardioverter-defibrillator (ICD) shocks compared with 4 without AF-AFl (36% vs. 9%, P=0.03). AF-AFl was more prevalent in heart-transplant patients and those who died of cardiac causes (56% vs. 16%, P=0.014). CONCLUSIONS: AF-AFl is associated with inappropriate ICD shocks, heart transplantation, and cardiac death in patients with ARVD. Evidence of reduced RV function and atrial dilation helps to identify the ARVD patients at increased risk for AF-AFl.

Characterization of Pulmonary Vein Dimensions Using High-Definition 64-Slice Computed Tomography prior to Radiofrequency Catheter Ablation for Atrial Fibrillation.

Background. Contrast-enhanced computed tomography is commonly acquired before radiofrequency catheter ablation (RFCA) for atrial fibrillation (AFib) to guide the procedure. We analyzed pulmonary vein (PV) ostial diameter and volumes on a high-definition 64-slice CT (HDCT) scanner in patients with AFib prior to RFCA. Methods and Results. This retrospective study included 50 patients (mean age 60.2 ± 11.4 years, 30 males) undergoing cardiac HDCT scanning before RFCA for drug refractory AFib and 50 age-, BMI-, and sex-matched controls with normal sinus rhythm undergoing HDCT. PV ostial diameter and volume were measured and calculated using a semiautomatic calliper tool. Total ostial PV volume was significantly increased in patients with AFib as compared to controls (P < 0.005). Similarly, total ostial PV diameter was significantly increased in AFib compared to controls (P < 0.001). In AFib, the largest PV volume and diameters were measured in right superior PV (P < 0.05 versus controls). The difference in PV volume between patients and controls was most pronounced in right superior PVs (P = 0.015). Right middle PVs were found more often in patients with AFib (16/50; 32%) than in normal subjects (7/50; 14%). Conclusion. Enlargement of PV ostial area and enlargement of volume are frequent findings in patients with drug refractory AFib. These parameters may add to the risk stratification for AFib recurrence following RFCA.

Long-term performance of modern coronary sinus leads in cardiac resynchronization therapy.

BACKGROUND: Cardiac resynchronization therapy (CRT) has become an important pillar of contemporary heart failure therapy. The efficacy of CRT, however, critically relies on proper LV lead placement and performance, which is why data regarding the long-term performance of CS leads are of considerable interest. Available studies are limited by a restricted variety of lead vendors, earlier lead models and / or very short follow-up periods. In the current study, we therefore investigated the long-term performance of modern LV leads in a large "real world" cohort of patients undergoing CRT implantation. METHODS AND RESULTS: All 193 patients who had successfullyundergone CRT implantation at the University Hospital Zurich between September 2003 and January 2010 were included in the study. An overall stable course of stimulation energy was observed over time; neither ischemic etiology, lead configuration, or severely reduced EF had an influence on the evolution of energy thresholds over time. Interestingly, patients with a high energy threshold at baseline experienced a significant reduction during follow-up. In contrast, a significant drop in impedance was seen following implantation, followed by a steady course for the rest of the observation period. Only 15 patients (9.7%) showed an impedance > 1000 Ohm at any time during their follow-up. Seven lead dislocations were observed during follow up. CONCLUSION: The current comprehensive analysis of long-term performance of modern coronary sinus leads demonstrates excellent stability, performance and safety. These data may have important implications for physicians involved in biventricular pacemaker implantations and in the follow-up care of these patients.

Usefulness of electrocardiographic parameters for risk prediction in arrhythmogenic right ventricular dysplasia.

The value of electrocardiographic findings predicting adverse outcome in patients with arrhythmogenic right ventricular dysplasia (ARVD) is not well known. We hypothesized that ventricular depolarization and repolarization abnormalities on the 12-lead surface electrocardiogram (ECG) predict adverse outcome in patients with ARVD. ECGs of 111 patients screened for the 2010 ARVD Task Force Criteria from 3 Swiss tertiary care centers were digitized and analyzed with a digital caliper by 2 independent observers blinded to the outcome. ECGs were compared in 2 patient groups: (1) patients with major adverse cardiovascular events (MACE: a composite of cardiac death, heart transplantation, survived sudden cardiac death, ventricular fibrillation, sustained ventricular tachycardia, or arrhythmic syncope) and (2) all remaining patients. A total of 51 patients (46%) experienced MACE during a follow-up period with median of 4.6 years (interquartile range 1.8 to 10.0). Kaplan-Meier analysis revealed reduced times to MACE for patients with repolarization abnormalities according to Task Force Criteria (p = 0.009), a precordial QRS amplitude ratio (∑QRS mV V1 to V3/∑QRS mV V1 to V6) of ≤ 0.48 (p = 0.019), and QRS fragmentation (p = 0.045). In multivariable Cox regression, a precordial QRS amplitude ratio of ≤ 0.48 (hazard ratio [HR] 2.92, 95% confidence interval [CI] 1.39 to 6.15, p = 0.005), inferior leads T-wave inversions (HR 2.44, 95% CI 1.15 to 5.18, p = 0.020), and QRS fragmentation (HR 2.65, 95% CI 1.1 to 6.34, p = 0.029) remained as independent predictors of MACE. In conclusion, in this multicenter, observational, long-term study, electrocardiographic findings were useful for risk stratification in patients with ARVD, with repolarization criteria, inferior leads TWI, a precordial QRS amplitude ratio of ≤ 0.48, and QRS fragmentation constituting valuable variables to predict adverse outcome.