Post-transcatheter aortic valve implantation isolated PR prolongation: incidence and clinical significance.

AIMS: Conduction abnormalities post-transcatheter aortic valve implantation (TAVI) are common. Post-TAVI PR prolongation was mainly studied as an adjunct to new-onset bundle branch block. The net effect of isolated PR prolongation (IPRP) without post-TAVI QRS changes is not well known. The aim of this study was to define the incidence and clinical significance of post-TAVI IPRP. METHODS AND RESULTS: A total of 1108 consecutive TAVI patients were reviewed. Patients with IPRP were compared with patients without post-TAVI electrocardiogram (ECG) changes. Clinical outcomes included permanent pacemaker implantation (PPI) and overall mortality. A total of 146 patients with IPRP were compared with 290 patients without post-TAVI ECG changes. At 1 year follow-up, 4 (2.7%) and 7 (2.4%) patients underwent PPI (P = 0.838) and 10 (6.8%) and 25 (8.6%) died (P = 0.521), from the study and control groups, respectively. No patient with IPRP and narrow QRS underwent PPI during 1 year post-TAVI, and all death events were non-cardiac except one unknown cause. Permanent pacemaker implantation rates among patients with IPRP and wide QRS were higher (n = 4, 12.1%), compared with patients with wide QRS without post-TAVI ECG change (n = 3, 4%) however not reaching statistical significance (P = 0.126). Multivariate Cox proportional hazards model demonstrated that in patients with narrow QRS, neither PR prolongation nor baseline or maximal PR intervals was associated with the combined endpoint of PPI and mortality. However, in patients with wide QRS, baseline PR intervals and QRS width, but not PR prolongation were associated with the combined outcome. CONCLUSION: Post-TAVI IPRP in patients with narrow QRS is not associated with adverse outcome. This finding may translate clinically into a more permissive approach to these patients.

Electrocardiographic findings in patients with arrhythmogenic cardiomyopathy and right bundle branch block ventricular tachycardia.

AIMS: Little is known about patients with right bundle branch block (RBBB)-ventricular tachycardia (VT) and arrhythmogenic cardiomyopathy (ACM). Our aims were: (i) to describe electrocardiogram (ECG) characteristics of sinus rhythm (SR) and VT; (ii) to correlate SR with RBBB-VT ECGs; and (iii) to compare VT ECGs with electro-anatomic mapping (EAM) data. METHODS AND RESULTS: From the European Survey on ACM, 70 patients with spontaneous RBBB-VT were included. Putative left ventricular (LV) sites of origin (SOOs) were estimated with a VT-axis-derived methodology and confirmed by EAM data when available. Overall, 49 (70%) patients met definite Task Force Criteria. Low QRS voltage predominated in lateral leads (n = 37, 55%), but QRS fragmentation was more frequent in inferior leads (n = 15, 23%). T-wave inversion (TWI) was equally frequent in inferior (n = 28, 42%) and lateral (n = 27, 40%) leads. TWI in inferior leads was associated with reduced LV ejection fraction (LVEF; 46 ± 10 vs. 53 ± 8, P = 0.02). Regarding SOOs, the inferior wall harboured 31 (46%) SOOs, followed by the lateral wall (n = 17, 25%), the anterior wall (n = 15, 22%), and the septum (n = 4, 6%). EAM data were available for 16 patients and showed good concordance with the putative SOOs. In all patients with superior-axis RBBB-VT who underwent endo-epicardial VT activation mapping, VT originated from the LV. CONCLUSIONS: In patients with ACM and RBBB-VT, RBBB-VTs originated mainly from the inferior and lateral LV walls. SR depolarization and repolarization abnormalities were frequent and associated with underlying variants.

Anatomical accuracy of the KODEX-EPD novel 3D mapping system of the left atrium during pulmonary vein isolation: A correlation with computer tomography imaging.

BACKGROUND: A novel 3D mapping system (KODEX-EPD, EPD Solutions) enables catheter localization and real-time 3D cardiac mapping. OBJECTIVE: To evaluate left atrium (LA) anatomical mapping accuracy created by the KODEX-EPD system during pulmonary vein isolation (PVI) compared with gold standard computed tomography (CT) images acquired from the same patients before the procedure. METHODS: In 15 consecutive patients who underwent PVI, 3D mapping of the LA was created on the KODEX-EPD system using the Achieve catheter. Pulmonary vein (PV), posterior wall, and appendage anatomy and diameters, were compared to the CT 3D reconstruction measured on the CARTO 3 system. Measurements were done independently by two physicians in each method. Linear correlation and agreement between CT and EPD measurements were assessed by Spearman correlation and Bland-Altman plot. RESULTS: Mean LA mapping time was 7.7 ± 3.6 min. Very high interobserver correlation was found for both EPD and CT measurements (Spearman r = .9). High correlation (r = .75) was found between CT and EPD measurements. Bland-Altman plot method revealed that measurements assessed by EPD were slightly higher than those assessed by CT. Mean difference was 3.5 mm, p < .01. In 2 (13.5%) patients each, disagreement regarding the presence of a left common PV and a right middle accessory vein anatomy was seen. CONCLUSION: The new KODEX-EPD mapping system allows quick and accurate mapping of the LA with high correlation to CT imaging. Some differences in left common and accessory right middle vein anatomy were seen.

Lead fixation mechanism impacts outcome of transvenous lead extraction: data from the European Lead Extraction ConTRolled Registry.

AIMS: The aims of this study is to characterize the transvenous lead extraction (TLE) population with active (A) compared with passive fixation (PFix) leads and to compare the safety, efficacy, and ease of extracting active fixation (AFix) compared with PFix right atrial (RA) and right ventricular (RV) leads. METHODS AND RESULTS: The European Lead Extraction ConTRolled Registry (ELECTRa) was analysed. Patients were divided into three groups; those with only AFix, only PFix, and combined Fix leads. Three outcomes were defined. Difficult extraction, complete radiological, and clinical success. Multivariate model was used to analyse the independent effect of Fix mechanism on these outcomes. The study included 2815 patients, 1456 (51.7%) with only AFix leads, 982 (34.9%) with only PFix leads, and 377 (13.4%) with combined Fix leads. Patients with AFix leads were younger with shorter lead dwelling time. Infection was the leading cause for TLE among the combined Fix group with lowest rates among AFix group. No difference in complications rates was noted between patients with only AFix vs. PFix leads. Overall, there were 1689 RA (1046 AFix and 643 PFix) and 2617 RV leads (1441 AFix and 1176 PFix). Multivariate model demonstrated that PFix is independently associated with more difficult extraction for both RA and RV leads, lower radiological success in the RA but has no effect on clinical success. CONCLUSION: Mechanism of Fix impact the ease of TLE of RA and RV leads and rates of complete radiological success in the RA but not clinical success. These findings should be considered during implantation and TLE procedures.

Polymorphic ventricular tachycardia, ischaemic ventricular fibrillation, and torsade de pointes: importance of the QT and the coupling interval in the differential diagnosis.

AIMS: Distinctive types of polymorphic ventricular tachycardia (VT) respond differently to different forms of therapy. We therefore performed the present study to define the electrocardiographic characteristics of different forms of polymorphic VT. METHODS AND RESULTS: We studied 190 patients for whom the onset of 305 polymorphic VT events was available. The study group included 87 patients with coronary artery disease who had spontaneous polymorphic VT triggered by short-coupled extrasystoles in the absence of myocardial ischaemia. This group included 32 patients who had a long QT interval but nevertheless had their polymorphic VT triggered by ectopic beats with short coupling interval, a subcategory termed 'pseudo-torsade de pointes] (TdP). For comparison, we included 50 patients who had ventricular fibrillation (VF) during acute myocardial infarction ('ischaemic VF' group) and 53 patients with drug-induced TdP ('true TdP' group). The QT of patients with pseudo-TdP was (by definition) longer than that of patients with polymorphic VT and normal QT (QTc 491.4 ± 25.2 ms vs. 447.3 ± 55.6 ms, P < 0.001). However, their QT was significantly shorter than that of patients with true TdP (QTc 564.6 ± 75.6 ms, P < 0.001). Importantly, the coupling interval of the ectopic beat triggering the arrhythmia was just as short during pseudo-TdP as during polymorphic VT with normal QT (359.1 ± 38.1 ms vs. 356.6 ± 39.4 ms, P = 0.467) but was much shorter than during true TdP (581.2 ± 95.3 ms, P < 0.001). CONCLUSIONS: The coupling interval helps discriminate between polymorphic VT that occurs despite a long QT interval (pseudo-TdP) and polymorphic arrhythmias striking because of a long QT (true TdP).

Quinidine-Responsive Polymorphic Ventricular Tachycardia in Patients With Coronary Heart Disease.

BACKGROUND: Polymorphic ventricular tachycardia (VT) without QT prolongation is well described in patients without structural heart disease (mainly idiopathic ventricular fibrillation and Brugada syndrome) and in patients with acute ST-elevation myocardial infarction. METHODS: Retrospective study of patients with polymorphic VT related to coronary artery disease, but without evidence of acute myocardial ischemia. RESULTS: The authors identified 43 patients in whom polymorphic VT developed within days of an otherwise uncomplicated myocardial infarction or coronary revascularization procedure. The polymorphic VT events were invariably triggered by extrasystoles with short (364±36 ms) coupling interval. Arrhythmic storms (4-16 events of polymorphic VT deteriorating to ventricular fibrillation) occurred in 23 (53%) patients. These arrhythmic storms were always refractory to conventional antiarrhythmic therapy, including intravenous amiodarone, but invariably responded to quinidine therapy. In-hospital mortality was 17% for patients with arrhythmic storm. Patients treated with quinidine invariably survived to hospital discharge. During long-term follow-up (of 5.6±6 years; range, 1 month to 18 years), 3 (16%) of patients discharged without quinidine developed recurrent polymorphic VT. There were no recurrent arrhythmias during quinidine therapy Conclusions: Arrhythmic storm with recurrent polymorphic VT in patients with coronary disease responds to quinidine therapy when other antiarrhythmic drugs (including intravenous amiodarone) fail.

The Utility of Prophylactic Pacemaker Implantation in Right Bundle Branch Block Patients Pre-Transcatheter Aortic Valve Implantation.

BACKGROUND: Patients with right bundle branch block (RBBB) prior to transcatheter aortic valve implantation (TAVI) are at high risk for immediate post-procedural heart block and long-term mortality when discharged without a pacemaker. OBJECTIVES: To test whether prophylactic permanent pacemaker implantation (PPI) is beneficial. METHODS: Of 795 consecutive patients who underwent TAVI, 90 patients had baseline RBBB. We compared characteristics and outcomes of the prophylactic PPI with post-TAVI PPI. Need for pacing was defined as  greater than 1% ventricular pacing. RESULTS: Forty patients with RBBB received a prophylactic PPI (group 1), and in 50 the decision was based on standard post-procedural indications (group 2). There were no significant differences in clinical baseline characteristics. One patient developed a tamponade after a PPI post-TAVI. A trend toward shorter hospitalization duration in group 1 patients was observed (P = 0.06). On long-term follow-up of 848 ± 56 days, no differences were found in overall survival (P = 0.77), the composite event-free survival of both mortality and hospitalizations (P = 0.66), or mortality and syncope (P = 0.65). On multivariate analysis, independent predictors of the need for pacing included baseline PR interval increase of 10ms (odds ratio [OR] 1.21 per 10 ms increment 95% confidence interval [95%CI] 1.02-1.44, P = 0.028), and the use of new generation valves (OR 3.92, 95%CI 1.23-12.46, P = 0.023). CONCLUSIONS: In patients with baseline pre-TAVI RBBB, no outcome differences were found with prophylactic PPI. On multivariate analysis, predictors of the need for pacing included baseline long PR interval, and the use of newer generation valves.

Catheter Induced Mechanical Suppression of Outflow-tract Arrhythmias: Incidence, Characteristics, and Significance.

BACKGROUND: The incidence, characteristics, and clinical significance of catheter-induced mechanical suppression (trauma) of ventricular arrhythmias originating in the outflow tract (OT) area have not been thoroughly evaluated. OBJECTIVES: To determine these variables among our patient cohort. METHODS: All consecutive patients with right ventricular OT (RVOT) and left ventricular OT (LVOT) arrhythmias ablated at two medical centers from 1998 to 2014 were included. Patients were observed for catheter-induced trauma during ablation procedures. Procedural characteristics, as well as response to catheter-induced trauma and long term follow-up, were recorded. RESULTS: During 288 ablations of OT arrhythmias in 273 patients (RVOT n=238, LVOT n=50), we identified 8 RVOT cases (3.3%) and 1 LVOT (2%) case with catheter-induced trauma. Four cases of trauma were managed by immediate radiofrequency ablation (RFA), three were ablated after arrhythmia recurrence within a few minutes, and two were ablated after > 30 minutes without arrhythmia recurrence. Patients with catheter-induced trauma had higher rates of repeat ablations compared to patients without: 3/9 (33%) vs. 12/264 (0.45%), P = 0.009. The three patients with arrhythmia recurrence were managed differently during the first ablation procedure (immediate RFA, RFA following early recurrence, and delayed RFA). During the repeat procedure of these three patients, no catheter trauma occurred in two, and in one no arrhythmia was observed. CONCLUSIONS: Significant catheter-induced trauma occurred in 3.1% of OT arrhythmias ablations, both at the RVOT and LVOT. Arrhythmia suppression may last > 30 minutes and may interfere with procedural success. The optimal mode of management following trauma is undetermined.

Use of New Imaging CARTO® Segmentation Module Software to Facilitate Ablation of Ventricular Arrhythmias.

INTRODUCTION: A new imaging software (CARTO® Segmentation Module, Biosense Webster) allows preprocedural 3-D reconstruction of all heart chambers based on cardiac CT. We describe our initial experience with the new module during ablation of ventricular arrhythmias. METHODS AND RESULTS: Eighteen consecutive patients with idiopathic ventricular arrhythmias or ischemic ventricular tachycardia (VT) were studied. In the latter group, a combined endocardial and epicardial ablation was performed. Of the 14 patients with idiopathic arrhythmias, 12 were ablated in the outflow tract (OT), 1 in the midseptal left ventricle, and 1 at the left posterior fascicular area; acute successful ablation was achieved in 11 (78.6%) patients. The procedure was discontinued due to close proximity of the arrhythmia origin to the coronary arteries (CA) in 2 patients. Acute successful uncomplicated ablation was achieved in all 4 patients with ischemic VT. During ablation in the coronary cusps commissures, the CARTO® Segmentation Module accurately defined the cusps anatomy. The precise anatomic location provided by the module assisted in successfully ablating when information from activation mapping was not optimal, by ablating at the opposite side of the cusps. In addition, by demonstrating the precise location of the CA, it allowed safe ablation of arrhythmias that originated in close proximity to the CA both in the OT area and the epicardium, eliminating the need for repeat angiography. CONCLUSIONS: The CARTO® Segmentation Module is useful for accurate definition of the exact anatomic location of ventricular arrhythmias and for safely ablating them especially in close proximity to the CA.

Exercise-induced albuminuria is related to metabolic syndrome.

Microalbuminuria (MA) is a known marker for endothelial dysfunction and future cardiovascular events. Exercise-induced albuminuria (EiA) may precede the appearance of MA. Associations between EiA and metabolic syndrome (MS) have not been assessed so far. Our aim was to investigate this association in a large sample of apparently healthy individuals with no baseline albuminuria. This was a cross-sectional study of 2,027 adults with no overt cardiovascular diseases who took part in a health survey program and had no baseline MA. Diagnosis of MS was based on harmonized criteria. All patients underwent an exercise test (Bruce protocol), and urinary albumin was measured before and after the examination. Urinary albumin-to-creatinine ratio (ACR) values before and after exercise were 0.40 (0.21-0.89) and 1.06 (0.43-2.69) mg/g for median (interquartile range) respectively. A total of 394 (20%) subjects had EiA; ACR rose from normal rest values (0.79 mg/g) to 52.28 mg/g after exercise (P < 0.001); this effect was not shown for the rest of the study population. EiA was related to higher prevalence of MS (13.8% vs. 27.1%, P < 0.001), higher metabolic equivalents (P < 0.001), higher baseline blood pressure (P < 0.001), and higher levels of fasting plasma glucose, triglycerides, and body mass index (P < 0.001). Multivariate binary logistic regression model showed that subjects with MS were 98% more likely to have EiA (95% confidence interval: 1.13-3.46, P = 0.016). In conclusion, EiA in the absence of baseline MA is independently related to MS.

Atrial Tachycardia Originating in the Vicinity of the Noncoronary Sinus of Valsalva: Report of a Series Including the First Case of Ablation-Related Complete Atrioventricular Block.

BACKGROUND: A few series of focal atrial tachycardia (AT) originating from the noncoronary sinus of Valsalva (NCSV) have been reported in the literature during the last decade. METHODS AND RESULTS: Of 147 patients with AT referred for radiofrequency ablation (RFA), we identified nine (6%) originating in the vicinity of the NCSV. Clinical AT was induced during electrophysiological study in all patients without (n = 6) and with (n = 3) isoproterenol infusion. Mean cycle length of the induced tachycardia was 399 ± 85 ms. Mapping of the right atrium and of the left atrium (LA) was initially performed in all nine patients and in four patients, respectively. Earliest tachycardia activation occurred at the His bundle area in all cases. Earliest activations in the LA were at the low paraseptal regions. In two patients with antegrade dual atrioventricular (AV) node physiology that rendered difficult accurate distinction between atrial and ventricular activation, slow pathway ablation was necessary. A retrograde aortic approach was used for mapping the aortic cusps. The earliest local atrial activation in the NCSV preceded the atrial activation in the His area in all patients by 27 ± 8 ms. RFA was performed in all nine patients and was acutely successful in eight. Two patients required radiofrequency (RF) energy outputs of 50 W in order to terminate the arrhythmia. In one patient, successful AT ablation was associated with complete AV block requiring implantation of permanent pacemaker. CONCLUSIONS: Focal AT can be successfully mapped and ablated in the NCSV. Higher than usual RF energy levels are sometimes required. Complete AV block is a possible complication.

Left Ventricular Outflow Tract Arrhythmias: Clinical Characteristics and Site of Origin.

BACKGROUND: Left ventricular outflow tract (LVOT) arrhythmias are increasingly recognized. Data regarding the distribution of the sites of origin (SOO) of the arrhythmias are sparse. OBJECTIVES: To describe the clinical characteristics of patients with LVOT arrhythmias and the distribution of their SOO. METHODS: All 42 consecutive patients with LVOT arrhythmias who underwent radiofrequency (RF) ablation during the period 2000-2014 were included. SOO identification was based on mapping activation, pace mapping and a 3D mapping system in eight patients. RESULTS: The study group comprised 28 males (66.7%) and 14 females, the mean age was 55 ± 15.4 years. Most patients (76%) were symptomatic. All suffered from high grade ventricular arrhythmias. Left ventricular (LV) dysfunction (ejection fraction ≤ 50%) was observed in 15 patients (35.7%), of whom 14 (93.3%) were males. The left coronary cusp (LCC) was the most common arrhythmia SOO (64.3%). Other locations were the right coronary cusp (RCC), the junction of the RCC-LCC commissure, aortic-mitral continuity, endocardial-LVOT, and a coronary sinus branch. Acute successful ablation was achieved in 29 patients (69%) and transient arrhythmia abolition in 40 (95.2%). There was a trend for a higher success rate using cooled tip ablation catheters as compared to standard catheters. The ablation procedure significantly improved LV function in all patients with tachycardiomyopathy. CONCLUSIONS: LVOT arrhythmias mostly originate from the LCC and are associated with LV dysfunction in 36% of patients. Knowledge regarding the prevalence of the anatomic origin of the LVOT arrhythmias may help achieve successful ablation. The use of cooled tip ablation catheters might have beneficial effects on the success rate of the procedure.

Incidence and Predictors for Recurrence of Ventricular Arrhythmia Presenting During Acute Myocarditis: A Multicenter Study.

BACKGROUND: Management of acute myocarditis (AM) patients experiencing ventricular arrhythmia (VA) during acute illness is controversial, especially regarding early implantable cardioverter-defibrillator (ICD) implantation. OBJECTIVES: The purpose of this study was to evaluate the prevalence of and find predictors for long-term sustained VA recurrence and overall mortality among AM patients with VA. METHODS: This was a multicenter retrospective analysis of AM patients (verified by cardiac magnetic resonance imaging or myocardial biopsy) with documented VA during the acute illness ("initial VA"). Patients with history of myocardial infarction, heart failure, or VA were excluded. The study endpoint was a composite of sustained VA and overall mortality during follow-up. RESULTS: The study included 69 AM patients with initial VA: sustained monomorphic ventricular tachycardia (MMVT) (n = 25), sustained polymorphic ventricular tachycardia (VT)/ventricular fibrillation (n = 13), and nonsustained VT (n = 31). Age was 44 ± 13 years, and 23 of 69 (33.3%) were women. During median follow-up of 5.5 years, 27 of 69 (39%) patients reached the composite endpoint including sustained VA (n = 24) and death (n = 11). Initial MMVT, predischarge left ventricular dysfunction (left ventricular ejection fraction <50%), and anteroseptal delayed enhancement on cardiac magnetic resonance imaging were significantly associated with the composite endpoint. On multivariable analysis, initial MMVT (HR: 5.17; 95% CI: 1.81-14.6; P = 0.001) and predischarge LV dysfunction (HR: 4.57; 95% CI: 1.83-11.5; P = 0.005) were independently associated with the composite endpoint. Using these 2 predictors, we could delineate subgroups with low (∼4%), medium (∼42%), and high (∼82%) 10-year incidence of composite endpoint. CONCLUSIONS: AM patients presenting with VA have high incidence of sustained VA recurrence and mortality posthospitalization. Initial MMVT and predischarge LV dysfunction are independently associated with VA recurrence and mortality. Implantable cardioverter-defibrillator implantation may be considered in such high-risk patients.

Cryoballoon-Induced Circumferential Pulmonary Vein Fibrosis, Assessed by Late Gadolinium-Enhancement Cardiac Magnetic Resonance Imaging, and Its Correlation with Clinical Atrial Fibrillation Recurrence.

BACKGROUND: Prior studies evaluating post-atrial fibrillation (AF) ablation pulmonary vein (PV) ostial gaps via magnetic resonance imaging (MRI) have shown circumferential PV fibrosis in a minority of patients, and their correlation with AF recurrence was weak. These studies were mostly based on radio-frequency AF ablations. AIM: We aimed to assess cryoballoon ablation-induced PV fibrosis via MRI and its correlation with AF recurrence. METHODS AND RESULTS: This was a prospective study of consecutive patients with symptomatic AF who underwent pre- and post-ablation MRI to assess baseline and ablation-induced fibrosis, respectively. Post-ablation PV gaps were assessed by new semi-quantitative visual analysis assisted by computerized ADAS analysis. AF recurrence monitored via multiple ECGs and event monitoring at 6 and 12 months post ablation. Nineteen patients with 80 PVs were included, age 56 ± 11, with paroxysmal and persistent AF in 17/19 and 2/19 patients, respectively. Baseline MRI showed minimal LA fibrosis. All patients underwent successful cryoballoon PV electrical isolation. Post-ablation MRI revealed circumferential PV fibrosis among 63/80 (78.8%) PVs and partial fibrosis with major gaps among 17/80 (21.2%) PVs. AF recurred within one year in 5/9 (55.5%) patients with partial PV fibrosis, while no AF recurred among the 10 patients in whom all PVs had circumferential fibrosis (p < 0.01). Similarly, there were significantly more PVs without circumferential fibrosis (due to major gaps) among patients with AF recurrence as compared with patients without AF recurrence (42.9% vs. 13.5%; p < 0.01). CONCLUSION: Cryoballoon AF ablation results in circumferential PV fibrosis in the majority of PVs, as assessed by a new clinically relevant MRI-LGE analysis. Significant correlation was found between major PV gaps on post-ablation MRI and AF recurrence, suggesting that MRI might have the ability to predict AF recurrence.

Short-Coupled Idiopathic Ventricular Fibrillation: A Literature Review With Extended Follow-Up.

Idiopathic ventricular fibrillation is responsible for approximately 5%-7% of cases of aborted cardiac arrest. Recent studies have shown that short-coupled ventricular premature complexes are present at the onset of idiopathic ventricular fibrillation in 6.6%-17% of patients. The present review provided information on 86 patients with short-coupled malignant ventricular arrhythmias that were reported as case reports or small patient series during the last 70 years. In 75% of the 81 cases published during the last 40 years, extended information and follow-up (from 2.63 ± 4.5 years to 10.67 ± 7.8 years; P < 0.001, between the original publication to the latest update) could be obtained from the authors. The review shows that short-coupled malignant ventricular arrhythmias occurred almost equally in males and females, at the mean age of 40 years. A tendency for later occurrence of the arrhythmia by 4 years was observed in females. A prior history of syncope was noted in 45.3% of the patients, whereas arrhythmic storm occurred in 42% at presentation. The most common mode of revelation of short-coupled malignant ventricular arrhythmias was syncope (53.5%), followed by aborted cardiac arrest (26.7%) and recurrent arrhythmic event after prior implantable-cardioverter defibrillator implantation for idiopathic ventricular fibrillation (17.4%). For the first time, short-coupled malignant arrhythmias exhibiting "not-so-short" coupling intervals (≥350 milliseconds) were found in a significant proportion of patients (17.4%). During long-term follow-up, quinidine yielded a slightly higher success rate in arrhythmia control than ablation. Larger studies are necessary to assess the best strategy for the management of this potentially lethal arrhythmia.

Red Flags in Syncope: Clues for the Diagnosis of Idiopathic Ventricular Fibrillation.

Idiopathic ventricular fibrillation is responsible for ≈5%-7% of aborted cardiac arrest, mainly striking subjects in their forties. Syncope caused by short-coupled rapid polymorphic ventricular tachycardia is frequently noted in a patient's past history. However, a diagnosis of neurally mediated syncope, the most frequent cause of syncope in the young, is often erroneously made. Clinical clues suggest that syncope has an arrhythmic rather than a neurally mediated origin. In addition, the presence of premature ventricular contractions on an electrocardiogram recorded shortly after a syncopal event has utmost importance in establishing the cause of syncope. Although such extrasystoles are frequently benign, especially when associated with a long coupling interval, they also may suggest a malignant origin when closely coupled to the preceding complex with short coupling intervals (usually <350 ms). These arrhythmias mainly originate from the Purkinje system (usually the right ventricle in men and the left ventricle in women) and favorably respond to quinidine as well as to ablation therapy targeting Purkinje-fibers ectopic activity.

Implantation of cardiac electronic devices in active COVID-19 patients: Results from an international survey.

BACKGROUND: Cardiac implantable electronic device (CIED) implantation rates as well as the clinical and procedural characteristics and outcomes in patients with known active coronavirus disease 2019 (COVID-19) are unknown. OBJECTIVE: The purpose of this study was to gather information regarding CIED procedures during active COVID-19, performed with personal protective equipment, based on an international survey. METHODS: Fifty-three centers from 13 countries across 4 continents provided information on 166 patients with known active COVID-19 who underwent a CIED procedure. RESULTS: The CIED procedure rate in 133,655 hospitalized COVID-19 patients ranged from 0 to 16.2 per 1000 patients (P <.001). Most devices were implanted due to high-degree/complete atrioventricular block (112 [67.5%]) or sick sinus syndrome (31 [18.7%]). Of the 166 patients in the study survey, the 30-day complication rate was 13.9% and the 180-day mortality rate was 9.6%. One patient had a fatal outcome as a direct result of the procedure. Differences in patient and procedural characteristics and outcomes were found between Europe and North America. An older population (76.6 vs 66 years; P <.001) with a nonsignificant higher complication rate (16.5% vs 7.7%; P = .2) was observed in Europe vs North America, whereas higher rates of critically ill patients (33.3% vs 3.3%; P <.001) and mortality (26.9% vs 5%; P = .002) were observed in North America vs Europe. CONCLUSION: CIED procedure rates during known active COVID-19 disease varied greatly, from 0 to 16.2 per 1000 hospitalized COVID-19 patients worldwide. Patients with active COVID-19 infection who underwent CIED implantation had high complication and mortality rates. Operators should take these risks into consideration before proceeding with CIED implantation in active COVID-19 patients.

Use of Electrophysiological Studies in Transcatheter Aortic Valve Implantation.

New conduction disturbances requiring permanent pacemaker implantation remain common complications following transcatheter aortic valve implantation (TAVI). It has been suggested that electrophysiological studies could help identify patients who will require permanent pacemaker implantation after TAVI. This article summarises contemporary data on the use of electrophysiological studies in patients undergoing TAVI.