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Objectives This study sought to identify electrocardiographic (ECG) and clinical predictors of sudden cardiac arrest (SCA) in sarcoidosis. Background Sudden cardiac death (SCD) is the leading cause of death in cardiac sarcoidosis (CS) and may be the earliest manifestation of disease. Widespread or repeated advanced imaging is a challenging solution to this problem. ECG is an affordable and widely accessible modality that could help guide diagnostic approaches and risk stratification. Methods Data were obtained from the National Inpatient Sample (2005–2017) using International Classification of Diseases-9th Revision and -10th Revision-Clinical Modification. The primary outcome was to identify predictors of SCA, whereas predictors of SCA in young individuals and those with normal ventricular function served as secondary measures. Furthermore, temporal trends in sarcoidosis as well as SCA were also analyzed. Logistic regression analysis was used to calculate odds ratios, following which a multivariable regression was used to adjust for potential confounders. Results Electrocardiographic markers of AV node dysfunction or bundle branch block are associated with substantially increased risk of SCA in a limited proportion of patients (8.6%). This association is also observed among younger patients ( Conclusions ECG evidence of AV nodal dysfunction or distal conduction disease should raise suspicion for cardiac involvement in patients with sarcoidosis and are associated with increased risk of SCA. ECG markers could help identify patients who would benefit from advanced imaging. The sensitivity of ECGs is, however, limited and presence of a normal ECG does not reflect a low risk of SCA.

Intracardiac echocardiography (ICE) use during catheter ablation of atrial fibrillation (AF) provides real-time information to guide transseptal access, for monitoring the ablation and recognition of pericardial bleed. We describe trends of ICE use, impact on complications, and its in-hospital outcomes. The national in-patient sample database was queried from 2001 to 2014 for diagnosis of AF based on ICD-9-CM 427.31 with a catheter ablation procedure code (37.34) in the same hospitalization and its associated complications. ICE was identified using ICD-9-CM procedure code (37.28). Statistical Analysis System (SAS) was used for analysis. There was an estimated total 299,152 patients who underwent AF ablation from 2001 to 2014 of which ICE was used in 46,688 (15.6%) patients. The use of ICE significantly increased from 0.08% in 2001 to 15.7% in 2014. In-hospital mortality was significantly lower in patients in whom ICE was used (0.11% vs 0.54%, p

Background Patients with cardiac amyloidosis (CA) have increased mortality, which can be explained in part by an increased risk of arrhythmias. The burden of arrhythmias in CA, their predictors, and impact on in‐hospital outcomes remains unclear. The role of implantable cardioverter‐defibrillators (ICD) in this population is also uncertain. Methods We queried the National Inpatient Sample (NIS) using ICD‐9‐CM codes 277.39 and 425.7 to identify CA. Twelve common arrhythmias were extracted using appropriate, validated ICD‐9‐CM codes. ICD implantation was identified using procedure ICD‐9 codes 37.94 to 37.98, 00.51 and 00.54. Results There were a total of 145,920 CA hospitalizations between 1999 and 2014 in the United States and 56,199 (38.5%) of them were associated with arrhythmias. The prevalence of arrhythmias remained relatively constant from 41.5% in 1999 to 40.2% in 2014. The most common arrhythmia was atrial fibrillation (25.4%). In‐patient mortality was significantly higher in CA patients with arrhythmias (10.4% vs 6.5%, P, Arrhythmias are common in patients with Cardiac amyloidosis with most common being atrial fibrillation. These are associated with worse in‐hospital outcomes, increased length of stay, and cost of hospitalization.

Electrophysiology (EP) procedures carry the risk of kidney injury due to contrast/hemodynamic fluctuations. We aim to evaluate the national epidemiology of acute kidney injury requiring dialysis (AKI-D) in patients undergoing EP procedures. Using the National Inpatient Sample, we included 2,747,605 adult hospitalizations undergoing invasive diagnostic EP procedures, ablation and implantable device placement from 2006 to 2014. We examined the temporal trend of AKI-D and outcomes associated with AKI-D. The rate of AKI-D increased significantly in both diagnostic/ablation group (8-21/10,000 hospitalizations from 2006 to 2014, P = 0.02) and implanted device group (19-44/10,000 hospitalizations from 2006 to 2014, P < 0.01), but it was explained by temporal changes in demographics and comorbidities. Cardiac resynchronization therapy and pacemaker placement had higher risk of AKI-D compared to implantable cardioverter-defibrillator placement (23 vs. 31 vs. 14/10,000 hospitalizations in cardiac resynchronization therapy, pacemaker placement, and implantable cardioverter-defibrillator group, respectively). Development of AKI-D was associated with significant increase in in-hospital mortality (adjusted odds ratio, 9.6 in diagnostic/ablation group, P < 0.01; adjusted odds ratio, 5.1 in device implantation group, P < 0.01) and with longer length of stay (22.5 vs. 4.5 days in diagnostic/ablation group, 21.1 vs. 5.7 days in implanted device group) and higher cost (282,775 vs. 94,076 USD in diagnostic/ablation group, 295,660 vs. 102,007 USD in implanted device group). The incidence of AKI-D after EP procedures increased over time but largely explained by the change of demographics and comorbidities. This increasing trend, however, was associated with significant increase in resource utilization and in-hospital mortality in these patients.

65-year-old man with a history of coronary artery disease s/p percutaneous coronary intervention to the left anterior descending artery and atrial fibrillation s/p recent (3 months) pulmonary vein isolation presented to the emergency department with symptoms of palpitations for 1 day after admittedly forgetting to take his medications found to be in a wide complex tachycardia. We discuss a stepwise approach using properties of the conduction system to diagnose the patient's tachycardia.

27-year-old male with incessant palpitations and reduced ejection fraction presents for diagnostic electrophysiology study. ECG shows a long RP tachycardia. Permanent junctional reciprocating tachycardia is diagnosed on EP study with successful ablation of posteroseptal accessory pathway.

Background Cardiac amyloidosis (CA) remains an underdiagnosed entity. Atrial fibrillation (AF) is common in patients with CA, likely owing to direct amyloid deposition in the left atrium. However, the prevalence of AF in CA and its association with in-hospital outcomes has not been studied in large populations. Purpose Our aim was to study the trends, baseline characteristics, and clinical impact of AF in patients with CA in the United States using the Healthcare Cost and Utilization Project (HCUP) National) Inpatient Sample (NIS) from 1999 to 2014. Methods We queried the NIS and identified CA using ICD-9-CM codes 277.39 and 425.7. AF in CA patients was identified using the ICD-9-CM code of 427.31. Statistical Analysis System (SAS) 9.4 was used for analysis of data. Results There were a total of 145,920 CA hospitalizations between 1999 and 2014 in the United States, of which 37,070 (25.4%) had AF. The prevalence of AF remained consistent from 27.5% in 1999 to 27.4% in 2014. The mean age of patients with AF was 72.9±28.2 years and for patients without AF was 67±31.9 years (p Inpatient mortality was significantly higher in CA patients with AF (10.4% vs 6.5%, p There was no significant difference between CA patients with and without AF in mean cost of hospitalization ($58222±10752 vs $57695±545, p=0.081) or length of stay (7.9±0.1 vs 7.7±0.1 days, p=0.7089). Conclusion CA with atrial fibrillation is a well-recognized entity, and our large scale retrospective analysis found significant association with worse in-hospital outcomes and cardiogenic shock. Interestingly, trend of in-patient mortality in CA has been decreasing over the years, likely owing to improved imaging modalities for diagnosis. Optimal management of AF in CA is imperative to improve outcomes in this population. Funding Acknowledgement Type of funding source: None

Key Clinical Message Inappropriate shock due to residual air in subcutaneous implantable cardiac defibrillators is not a well-known complication. Obtaining overpenetrated X-rays, recognizing electrocardiogram findings, limiting blunt finger dissection, and switching to sense at another vector are techniques which might lead to avoidance of unnecessary wound exploration or device removal.

The atrioventricular node (AV) is considered the electrical connection between the atria and ventricles. There is an electrical pause between activation of the atria and the ventricles (PR segment), but to date the mechanism responsible for this interruption remains unclear. The present communication focuses on the hypothesis that magnetic field dynamics could provide the answer. Proof of this hypothesis is that in Wolff-Parkinson-White syndrome, where there is physical connection between the atria and ventricles (bundle of Kent), there is electrical AV continuity, no PR segment is detected, and catheter ablation of the abnormal bundle restores AV discontinuity. Spontaneous initiation of the heart at the level of the sinus node, the pacemaker of the heart, could also be explained via field dynamics. The known transmembrane pacemaker protein CHN4, present in both sinoatrial and AV nodal cells, could interact with field information to provide specificity in an electronic key-to-lock mechanism interaction.

Cardiac sarcoidosis (CS) is highly underdiagnosed due to its often silent course. Sudden cardiac death (SCD) is a devastating and often index manifestation of cardiac involvement. In this study, we analyze the possible predictors of SCD in CS. We queried the National Inpatient Sample between 1999

Ventricular arrhythmias are common in patients with cardiac amyloidosis (CA) and are associated with increased mortality. The role of implantable cardiac defibrillator (ICD) in this population however remains unclear. We queried the National Inpatient Sample between 1999 and 2014 and CA was defined

Patients with cardiac amyloidosis (CA) have increased mortality, which can be explained in part by increased risk of arrhythmias. However, the burden of arrhythmias in CA, their predictors and impact on in-hospital outcomes is unclear. We queried the National Inpatient Sample and CA was identified

Left atrial appendage occlusion (LAAO) has emerged as an important stroke prevention therapy for atrial fibrillation (AF) patient in recent years. Despite increasing attentions to the long-term efficacy, little data is available about its 30-day readmission. Index admissions and 30-day readmissions

Intracardiac echocardiography (ICE) during atrial fibrillation (AF) ablation offers real time information to guide transseptal access, monitoring the lesion and recognition of pericardial bleed. We describe the trends in the use of ICE and its impact on in-hospital outcomes and complications.

Ablation of Atrial Arrhythmias in Cardiac Sarcoidosis Background We previously reported on the incidence and clinical implications of supraventricular arrhythmia in patients with cardiac sarcoidosis (CS). The role of catheter ablation for the management of atrial arrhythmia (AA) in this patient population is unknown. Methods and Results One hundred consecutive patients with CS were monitored for the incidence of supraventricular arrhythmias. Those with persistent symptoms despite optimal medical therapy proceeded to catheter ablation. Following ablation, all patients were followed serially with Holter monitoring or device interrogation. Thirty-two (32%) patients had symptomatic supraventricular arrhythmias. Nine (28%) patients had symptomatic AA requiring catheter ablation for clinical indications. Mean age was 55 ± 11.6 years. Five (56%) patients had atrial fibrillation (AF), of whom 2 also had cavotricuspid isthmus ablation. Four patients had isolated atrial flutter: 2 patients with left atrial flutter, and 2 patients with cavotricuspid flutter. All other arrhythmias were ablated in the left atrium. Mean duration of follow-up was 1.8 ± 1.9 years. One patient with atypical atrial flutter, and one patient with AF have had recurrence; the remaining patients remain in sinus rhythm. Conclusions Our study suggests that AA in CS is frequently left atrial in origin. Catheter ablation appears to be effective and safe for the maintenance of sinus rhythm in patients with CS.

Background Cardiac sarcoidosis (CS) is known to be associated with congestive heart failure, conduction disorders, and tachyarrhythmias. Ventricular arrhythmias are the most feared cardiac manifestation because they often are unpredictable, may be the first manifestation of the disease, and may be fatal. The propensity for the development of supraventricular arrhythmias (SVAs) in patients with CS has not been described. The aim of this study was to assess the prevalence as well as the predictors of SVA. Methods We retrospectively investigated 100 patients with biopsy specimen-proven systemic sarcoidosis and evidence of cardiac involvement (defined by cardiac biopsy specimen, PET scan, or cardiac MRI). The mean follow-up was 5.8 ± 3.6 years. ECG, Holter monitoring, implantable cardioverter defibrillator interrogations, or electrophysiology studies were used to document SVA. Echocardiographic data, demographics, and extracardiac involvement were recorded, and univariate and Poisson regressions were performed to compare characteristics of patients with and without documented SVA. Results The prevalence of SVA was 32%, and atrial fibrillation was the most common arrhythmia, comprising 18% of the total burden, followed by atrial tachycardias (7%), atrial flutter (5%), and other supraventricular tachycardias (2%). Of the patients with SVA, 96% were symptomatic. Left atrial enlargement (LAE) was more frequent in the group with SVA, with an incidence of 267.8 per 1,000 person-years, and it significantly increased the likelihood of SVA on multivariate analysis (risk ratio, 6.12; 95% CI, 2.19-17.11). Diastolic dysfunction, systemic hypertension, and right atrial enlargement were predictors of SVA on univariate analysis. Left ventricular hypertrophy, right ventricular dysfunction, tricuspid valve disease, pulmonary hypertension, and pulmonary sarcoidosis were not associated with SVA on univariate analysis. Conclusions The study systematically evaluated the frequency of SVA in a large number of patients with CS. SVA in patients with CS is frequent and associated with symptoms. LAE was clearly associated with the development of SVA in this patient population. The extent to which LAE predicts the occurrence of SVA in larger, more diverse CS populations should be evaluated prospectively.

Background— Cardiac involvement in sarcoidosis is often silent and may lead to sudden death. This study was designed to assess the value of programmed electric stimulation of the ventricle (PES) for risk stratification in patients with sarcoidosis and evidence of preclinical cardiac involvement on imaging studies. Methods and Results— Patients with biopsy-proven systemic sarcoidosis but without cardiac symptoms who had evidence of cardiac sarcoidosis on positron emission tomography (PET) or cardiac MRI (CMR) were included. All patients underwent baseline evaluation, echocardiographic assessment of left ventricular function, and programmed electric stimulation of the ventricle. Patients were followed for survival and arrhythmic events. Seventy-six patients underwent PES of the ventricle. Eight (11%) were inducible for sustained ventricular arrhythmias and received an implantable defibrillator. None of the noninducible patients received a defibrillator. Left ventricular ejection fraction was lower in patients with inducible ventricular arrhythmia (36.4±4.2% versus 55.8±1.5%, P P Conclusions— In patients with biopsy-proven sarcoidosis and evidence of cardiac involvement on PET or CMR alone, positive PES may help to identify patients at risk for ventricular arrhythmia. More importantly, patients in this cohort with a negative PES appear to have a benign course within the first several years following diagnosis. PES may help to guide the use of implantable cardioverter defibrillators in this population.

Periprocedural thromboembolic and hemorrhagic events are complications of percutaneous radiofrequency catheter ablation (RFA) of atrial fibrillation (AF). The management of anticoagulation before and after RFA could play an important role in the prevention of these complications. The incidence of thromboembolic events varies from 1% to 5%, depending on the ablation and the anticoagulation strategy used in the periprocedural period. The scientific evidence behind the management of anticoagulation in patients with AF undergoing RFA is scarce and is mostly based on small studies and experts' consensus. It remains unclear whether catheter ablation for AF reduces the risk of stroke and obviates the need for anticoagulation after the procedure. Limited data are available regarding the risk of thromboembolism with and without warfarin after AF ablation. In this review we will review the most current evidence supporting the different strategies to reduce thromboembolic risk before, during, and after catheter ablation for AF.

Studies suggest patients with atrial fibrillation (AF) who also suffer from obstructive sleep apnea (OSA) might have a different response to ablative procedures. It has been hypothesized that AF substrates and pathophysiology in these patients might be different from patients with primary AF. Data

Obesity is a predictor of worse outcomes in many cardiovascular diseases but studies suggest an obesity paradox exists in patients with heart failure, hypertension, peripheral vascular disease, and coronary artery disease. Obesity has been linked to increased incidence of atrial fibrillation (AF) as

Cardiac resynchronization therapy (CRT) is a well-established therapy for patients with moderate-to-severe heart failure (HF), left ventricular dysfunction with an ejection fractionor= 35% and a QRS on the surface electrocardiogram ofor=130 msec. Device optimization is often performed, adjusting the timing of RV and LV stimulation to produce a pacing sequence that yields the best global cardiac performance. However, no standard guidelines exist for optimization and many invasive and non-invasive techniques have been employed with mixed results. The aim of the present study was to determine whether there are any clinical predictors of the optimal V-V settings in patients implanted with CRT devices.We prospectively evaluated 47 consecutive patients with HF who were referred to our device optimization clinic. The mean patient age was 64.9 +/- 12.7 years. Patients were in both sinus rhythm (83%) and atrial fibrillation. Prior to device implant, 51% of patients had left bundle branch block (LBBB), 17% had intra-ventricular conduction delay (IVCD) and 21% were RV paced. Sixty-two percent were male, the mean QRS duration was 152 +/- 29 ms, mean LVEF 26 +/- 8% and 60% had a non-ischemic cardiomyopathy. Overall, 82% of patients required sequential pacing with 69% requiring LV pre-excitation to produce the best global cardiac function as determined by aortic velocity time integrals (VTI). In our cohort, none of the clinical characteristics evaluated, including etiology of the cardiomyopathy, QRS duration, LVEF, pre-implant rhythm or AV delay were predictive of an optimal simultaneous or sequential V-V setting.None of the clinical variables tested in our analysis predicted optimal RV-LV settings. Our results suggest that individual optimization and programming of V-V settings is necessary. The inability to predict optimal settings likely reflects the unique characteristics of each patient and supports the need for individualized programming of each device.

Background Simplifications of the Cox-Maze procedure to treat atrial fibrillation (AF) include epicardial pulmonary vein (PV) isolation using various sources to create lines of conduction block. The creation of transmural lesions has been a concern. The heat-sink effect caused by blood flow has limited the effectiveness of unipolar radiofrequency and linear application of cryothermy, which should be abolished when clamp devices are used for PV isolation. The efficacy and safety of epicardial beating-heart PV isolation with clamp devices using cryothermy or bipolar radiofrequency energy was studied. Methods Twelve domestic pigs underwent beating-heart epicardial PV isolation using cryothermy (n = 6) or radiofrequency (n = 6) energy. Follow-up was 30 days for 3 animals of each group and 90 days for the others. Lesions were assessed by epicardial pacing, cardiac magnetic resonance imaging (MRI), and histologic analysis. Results Immediate and long-term electrical isolation of PVs was achieved with both energy sources. Histologic analysis showed transmural lesions in all animals at 30 and 90 days. Cardiac MRI showed no evidence of PV stenosis or thrombus formation. Mean left atrial ejection fraction was 0.36 ± 0.01, 0.36 ± 0.02, and 0.36 ± 0.01 at baseline and at 30 and 90 days, respectively ( p = 0.360 and 0.230, respectively) and not significantly different with cryothermy or radiofrequency ablations. Conclusions Beating-heart PV isolation using epicardial cryothermy or radiofrequency ablation produces transmural lesions with complete electrical conduction block, with low or no risk of endocardial thrombosis or PV stenosis. This approach may be useful for PVI in selected patients with AF caused by PV triggers.

Background Cardiac sarcoidosis (CS) causes substantial morbidity and sudden death. Early diagnosis and risk stratification are warranted. Methods Ambulatory patients with sarcoidosis were interviewed to determine whether they experienced palpitations, syncope, or presyncope, and were evaluated with ECG, Holter monitoring, and echocardiography (transthoracic echocardiogram [TTE]). Those with symptoms or abnormal results were studied with cardiac MRI (CMRI) or positron emission tomography (PET) scanning. The diagnosis of CS was based on abnormalities detected by these imaging studies. Patients with CS were referred for risk stratification by electrophysiology study (EPS). Results Among the 62 patients evaluated, the prevalence of CS was 39%. Patients with CS had more cardiac symptoms than those without CS (46% vs 5%, respectively; p Conclusion CS is common among patients with sarcoidosis. A structured clinical assessment incorporating advanced cardiac imaging with PET scanning or CMRI is more sensitive than the established criteria for the identification of CS. Sarcoidal lesions seen on CMRI or PET scanning do not predict arrhythmias in ambulatory patients with preserved cardiac function, who appear to be at low risk for short-term mortality.

A case of successful laser extraction of a defibrillator lead with baffle stenting in a 15-year-old boy with dextrocardia, L-transposition, ventricular septal defect, and pulmonic stenosis status-post Senning/Rastelli repair is presented. Six-month follow-up revealed a significant increase in exercise tolerance and maximum oxygen consumption (VO(2)max).

Using cardiac magnetic resonance, the presence of myocardial delayed contrast enhancement (DCE) has been described in the ventricular septum at the level of the right ventricular insertion points in patients with pulmonary hypertension (PH). The aim of this study was to investigate the prevalence, extent, and correlates of this finding. Septal DCE was evaluated in 55 patients with known or suspected PH of various causes. The extent of DCE was estimated visually with an insertion enhancement score (range 0 to 4) and quantified as DCE mass. The results were correlated with cine magnetic resonance and right-sided cardiac catheterization. Predictors of DCE were investigated using multivariate analysis. PH at rest was present in 42 patients (group 1) and absent in 13 (group 2). DCE was noted in 41 patients (97%) in group 1 and 3 (23%) in group 2 (p

Cardiac sarcoidosis (CS) patients are at increased risk for sudden death. Isolated CS is rare and can be difficult to diagnose.In this multicenter retrospective review, patients with CS and an implantable cardiac defibrillator (ICD) were identified.Of 235 patients with CS and ICD, 13 (5.5 %) had isolated CS, including 7 (3.0 %) with definite isolated CS (biopsy or necropsy-proven) and 6 (2.6 %) with suspected isolated CS based on a constellation of clinical, ECG, and imaging findings. Among 13 patients with isolated CS, 10 (76.9 %) were male, mean age was 53.8 ± 7.6 years, and mean left ventricular ejection fraction was 38.3 ± 16.5. Diagnosis was made by cardiac magnetic resonance (CMR) (n = 2), biopsy (n = 3), CMR and biopsy (n = 2), CMR and positron emission tomography (PET) (n = 2), PET (n = 1), late enhanced cardiac CT (n = 1), pathology at heart transplant (n = 1), and autopsy (n = 1). Eight of 13 (61.5 %) patients with isolated CS had a secondary prevention indication (VT in 6 and VF in 2) vs. 80 of 222 (36.0 %) with sarcoidosis in other organs (p = 0.04). Over a mean of 4.2 years, 9 of 13 (69.2 %) patients with isolated CS received appropriate ICD therapy, including anti-tachycardia pacing (ATP) and/or shock, compared with 75 of 222 (33.8 %) patients with cardiac and extracardiac sarcoidosis (p = 0.0150). Six of 7 (85.7 %) patients with definite isolated CS received appropriate ICD intervention, compared with 78 of 228 patients (34.2 %) without definite isolated CS (p = 0.0192.)In this retrospective study, patients with isolated CS had very high rates of appropriate ICD therapy. Prospective, long-term follow-up of consecutive patients with isolated CS is needed to determine the true natural history and rates of ventricular arrhythmias in this rare and difficult-to-diagnose disease.

The utility of programmed ventricular stimulation to predict future arrhythmic events in patients with cardiac sarcoidosis is unknown. Similarly, the long-term benefit of implantable cardioverter-defibrillators (ICDs) in cardiac sarcoidosis has not been established. Thirty-two consecutive patients with cardiac sarcoidosis underwent programmed ventricular stimulation. Patients with spontaneous or inducible sustained ventricular arrhythmias (n = 12) underwent ICD insertion. All study patients were followed for the combined arrhythmic event end point of appropriate ICD therapies or sudden death. Mean length of follow-up to sustained ventricular arrhythmia or sudden death was 32 +/- 30 months. Five of 6 patients (83%) with spontaneous sustained ventricular arrhythmias and 4 of 6 patients (67%) without spontaneous but with inducible sustained ventricular arrhythmias received appropriate ICD therapy. Two of 20 patients (10%) with neither spontaneous nor inducible sustained ventricular arrhythmias experienced sustained ventricular arrhythmias or sudden death. Programmed ventricular stimulation predicted subsequent arrhythmic events in the entire population (relative hazard 4.47, 95% confidence interval [CI] 1.30 to 15.39) and in patients who presented without spontaneous sustained ventricular arrhythmias (relative hazard 6.97, 95% CI 1.27 to 38.27). No patient with an ICD died of a primary arrhythmic event. In patients with spontaneous or inducible sustained ventricular arrhythmias, mean survival from first appropriate ICD therapy to death or cardiac transplant was 60 +/- 46 months, with only 2 patients dying or reaching transplant at study end. In conclusion, programmed ventricular stimulation identifies patients with cardiac sarcoidosis at high risk for future arrhythmic events. ICDs effectively terminate life-threatening arrhythmias in high-risk patients, with significant survival after first appropriate therapy.

Background: Every year the number of cases of Takotsubo cardiomyopathy increases and it is still a disease with limited data and unclear treatment approach. We aim to describe the differences among gender in admission rates, admission month and inpatient mortality. Methods: This is a retrospective

Atrial fibrillation (Afib) has been associated with abnormal signal-averaged P wave (SAPW) parameters but whether SAPW is associated with the time course of these arrhythmias (persistent vs. paroxysmal, frequent vs. rare episodes) remains unknown. This article assesses the significance of SAPW duration in distinguishing patients with paroxysmal from those with persistent Afib. SAPW electrocardiogram was performed with a "double triggering" software system for acquisition and analysis of data. SAPW total duration (TD), X, Y, and Z leads magnitudes and vector signal magnitudes were measured offline. Optimal cutoff value between control and patient groups was determined by using a receiver operator characteristic curve. Data were analyzed to compare controls with patients groups and between patient groups according to time course of the arrhythmic history. Fifteen age-matched patients without a history of Afib and 55 patients with a history of Afib (33 with paroxysmal and 22 with persistent arrhythmia) were studied off antiarrhythmic drugs. Patients with history of persistent arrhythmia were studied within 2 days after electrical cardioversion to sinus rhythm. SAPW TD was the only parameter consistently associated with Afib. SAPW TD was 98 +/- 6 ms (mean +/- SD) in the control group, 127 +/- 19 ms in the pooled patients group (P =.0001); 122 +/- 20 ms for paroxysmal and 133 +/- 17 ms for the persistent Afib group (P =.04). Analysis of other SAPW parameters were not statistically significant. SAPW duration is a simple method to identify patients with history of Afib. A significantly longer SAPW TD characterizes patients with a history of persistent as opposed to paroxysmal Afib. Prolongation of SAPW TD possibly reflects more advanced electrophysiological changes, creating a more stable substrate that leads to persistence of the arrhythmia.

The role of epicardial mapping for radiofrequency (RF) catheter ablation of postmyocardial infarction monomorphic ventricular tachycardia (VT) is still under investigation. We present two septuagenarian patients with a history of myocardial infarction, poor left ventricular function, and drug-refractory monomorphic VT who were treated with RF catheter ablation. The first patient had a history of myocardial infarction, left ventricular aneurysm, and mitral valve replacement complicated by recurrent drug refractory VT and congestive heart failure. The second patient had ischemic cardiomyopathy and VT and was implanted with a cardioverter defibrillator and subsequently suffered repeated episodes of VT refractory to multiple antiarrhythmic drugs. In both patients, coronary sinus mapping was performed with a multipolar catheter as endocardial mapping did not reveal satisfactory sites for ablation. Epicardial catheter mapping provided stable electrograms and identification of areas of slow conduction during VT. RF lesions guided by epicardial mapping resulted in successful ablation of VT and no recurrence at long-term follow-up. This report emphasizes the potential usefulness of coronary sinus mapping as an adjuvant to endocardial mapping to guide VT ablation.

Thirty-seven patients with atrial flutter were studied with catheter mapping and radiofrequency ablation. Uncommon atrial flutter occurred in 20 out of 37 (54%) patients. Atrial endocardial mapping showed two types of uncommon atrial flutter. In 15 patients (group I) it was characterized by a single clockwise circuit whereas in 5 patients (Group II) it was characterized by the presence of more than one circuit and/or localized atrial fibrillation. RFA ablation was acutely successful in 14 out of 15 patients (93%) in Group I and in 2 out of 5 (40%) patients in Group II. On long-term follow-up a significantly larger number of patients in Group I versus Group II (86% vs 20%) remained free of atrial flutter recurrence. We conclude that uncommon atrial flutter is a heterogeneous entity involving one or more reentrant circuits. Uncommon atrial flutter with multiple circuits may not be suitable for RFA.

Adenosine has been demonstrated to reliably produce transient block of atrioventricular nodal (AVN) conduction, and has been advocated as a method of differentiating retrograde conduction via the atrioventricular node from accessory pathway conduction. However, the response of retrograde AVN to adenosine in patients with typical atrioventricular nodal reentry tachycardia (AVNRT) remains unclear. We evaluated 13 patients (mean age 45 +/- 20 years) with typical AVNRT prior to AVN modification. During right ventricular pacing, a rapid bolus of adenosine (0.2 mg/kg; maximum 18 mg) was administered. Adenosine sensitivity, defined by transient ventriculoatrial block, was observed in six patients, while in seven patients ventriculoatrial conduction was unaffected. An adenosine bolus administered during sinus rhythm or atrial pacing resulted in antegrade atrioventricular block in all the adenosine resistant patients in whom this was performed (n = 6). Comparisons of AVN electrophysiological characteristics between the adenosine sensitive and adenosine resistant patients were performed. There was no difference with respect to ventriculoatrial effective refractory period, ventriculoatrial Wenckebach, AVNRT cycle length, and His to atrial echo interval in AVNRT. However, there was a trend toward a longer antegrade fast pathway ERP in the adenosine sensitive group (P = 0.07). Electrophysiological properties do not predict retrograde AVN adenosine sensitivity. Adenosine does not cause retrograde AVN block in all patients with AVNRT, and therefore cannot reliably distinguish between retrograde conduction via the AVN or an accessory pathway.

Preexcitation developed post-operatively in a cardiac transplant recipient whose donor electrocardiogram was normal. An electrophysiology study revealed evidence of a mid-septal atrioventricular (AV) bypass tract. The patient is clinically well fourteen months after transplant and has intermittent preexcitation.

adiofrequency catheter ablation of accessory pathways has ecome a well-established therapy with a high rate of success. ntracardiac electrophysiologic study, mapping, and ablation of he pathway are typically performed either in sinus rhythm or uring AV reentrant tachycardia. However, atrial fibrillation ccurs commonly in these patients (11.5%–39%). It may be he presenting arrhythmia and can occur during the electrohysiologic study. Atrial fibrillation during electrophysiologic tudy makes mapping and catheter ablation difficult. Previous eports have described ablation of AV accessory pathways uring atrial fibrillation using an accessory pathway potential r earliest ventricular activation as a guide. Pathway potenial localization can be used to guide ablation of an atriofasicular (Mahaim) pathway during atrial fibrillation. However, ocalization of these potentials is different compared with AV athways, as illustrated in the following case.

Nonphysiological prolongation of PR intervals can lead to palpitations and shortness of breath similar to those seen with pacemaker syndrome. This has been shown to be related to diastolic mitral regurgitation.1 We present a case of intermittent first-degree AV block that was caused by premature ventricular contraction (PVC)–induced slow pathway conduction. Catheter ablation of the slow pathway and the PVC focus normalized the PR interval and abolished all symptoms. The patient is a 74-year-old women with a structurally normal heart who presented with palpitations, shortness of breath, dizziness, and decreased exercise tolerance. Event monitoring disclosed no sustained arrhythmia but revealed frequent PVCs. The PVCs had left bundle-branch block morphology and a normal QRS axis. The baseline PR interval was normal; however, prolonged periods of first-degree AV block (PR>500 ms) were noted. First-degree AV block was consistently initiated by PVCs (Figure 1A). Interestingly, appropriately timed PVCs just as consistently led to normalization of the PR interval (Figure 1B). In the absence of such appropriately timed PVCs, slow pathway conduction persisted. She did …

Heart disease is the leading cause of death in the United States. Probably the most feared complication of this disease is sudden cardiac death, which accounts for 350,000 to 400,000 deaths annually. Despite the large number of out-of-hospital cardiac arrests, only a small proportion of such patients will survive long enough to receive medical care and, of those, only a percentage will survive to hospital discharge. 1 Patients at particular risk of ventricular tachyarrhythmias and therefore sudden cardiac death (SCD) are those with congestive heart failure (CHF). An analysis of the Framingham data revealed an age-adjusted rate of SCD of 31.4 per 1000 for men with heart failure versus 5.7 per 1000 for men without heart failure (9.9/1000 and 1.8/1000, respectively, for women). 2 Although revascularization, ablation, surgery, or transplantation are options for certain patients, most do not qualify for such procedures. Therefore essentially only two widespread options exist: arrhythmia suppression by using available drug therapy or implantation of a cardiac defibrillator (ICD). Medical therapy. Large studies such as CONSENSUS and V-HEFT have demonstrated the usefulness ofvasodilators, particularly the angiotensin-converting enzyme inhibitors, in reducing mortality in patients with poor ventricular function, a, 4 In addition, past studies have suggested a possible role for beta blockers in reducing cardiac mortality in these patients.5, 6 However, neither of these agents has gained acceptance for sustained ventricular arrhythmias. As for the available class 1 agents, several

Appropriate medical therapy and revascularization play a pivotal role in preventing or treating myocardial infarction and left ventricular systolic dysfunction, thereby reducing the incidence of SCD. Nevertheless, the ever-growing population of diabetic patients with coronary artery disease, prior myocardial infarction, and left ventricular systolic dysfunction continue to comprise a high-risk population. Thus, appropriate screening and utilization of ICD therapy will remain essential modalities in the ongoing battle against SCD. The use of devices capable of both biventricular pacing and ICD therapy will continue to grow in the ongoing effort to improve both quality of life and mortality in patients with systolic congestive heart failure.

This review article discusses the electrophysiological basis of sinus node reentry, clinical features of sinus node reentry, and the management of this uncommon tachycardia with drugs and ablative therapy. It also proposes the use of the term "sinoatrial reentrant tachycardia" for this form of tachycardia.

Aims Implantable cardiac defibrillator (ICD) implantation is a class IIA recommendation for patients with cardiac sarcoidosis (CS). However, little is known about the efficacy and safety of ICDs in this population. The goal of this multicentre retrospective data review was to evaluate the efficacy and safety of ICDs in patients with CS. Methods and results Electrophysiologists at academic medical centres were asked to identify consecutive patients with CS and an ICD. Clinical information, ICD therapy history, and device complications were collected for each patient. Data were collected on 235 patients from 13 institutions, 64.7% male with mean age 55.6 ± 11.1. Over a mean follow-up of 4.2 ± 4.0 years, 85 of 234 (36.2%) patients received an appropriate ICD therapy (shocks and/or anti-tachycardia pacing) and 67 of 226 (29.7%) received an appropriate shock. Fifty-seven of 235 patients (24.3%) received a total of 222 inappropriate shocks. Forty-six adverse events occurred in 41 of 235 patients (17.4%). Patients who received appropriate ICD therapies were more likely to be male (73.8 vs. 59.6%, P = 0.0330), have a history of syncope (40.5 vs. 22.5%, P = 0.0044), lower left ventricular ejection fraction (38.1 ± 15.2 vs. 48.8 ± 14.7%, P ≤ 0.0001), ventricular pacing on baseline electrocardiogram (16.1 vs. 2.1%, P = 0.0002), and a secondary prevention indication (60.7 vs. 24.5%, P < 0.0001) compared with those who did not receive appropriate ICD therapies. Conclusion Patients with CS and ICDs are at high risk for ventricular arrhythmias. This population also has high rates of inappropriate shocks and device complications.

The diagnosis of subclinical myocardial disease in patients with ventricular tachycardias of right ventricular (RV) origin and no overt cardiac abnormalities is important, inasmuch as the presence of RV cardiomyopathy or arrhythmogenic dysplasia can be associated with a poor prognosis. To this end the relative value of symptoms, ECG features of ventricular tachycardia, signal-averaged ECGs, and RV echocardiograms as compared with endomyocardial biopsy findings was prospectively evaluated. Twenty-seven patients with chronic ventricular tachycardias with a left bundle branch block-like morphology, presumed to be of RV origin, were studied. Clinical examination findings, 12-lead ECGs in sinus rhythm, radiographs of the chest, coronary angiograms, and left ventricular cineangiograms were normal in all patients. RV biopsies were abnormal in 11 patients (41%) with findings suggestive of RV dysplasia or cardiomyopathy. A multivariate analysis showed a significant correlation between an abnormal biopsy and sustained ventricular tachycardia (p0.05), tachycardia with a superior frontal plane axis (p0.001), an abnormal signal-averaged ECG (p0.05), and an abnormal RV echocardiogram (p0.001). An abnormal RV echocardiogram was both a sensitive (73%) and a specific (94%) indicator of an abnormal RV biopsy. Sustained tachycardia although sensitive (90%) had a low specificity (56%). In comparison, a superior frontal plane axis of ventricular tachycardia and an abnormal signal-averaged ECG were indicative of high specificity and low sensitivity for abnormal myocardial histologic findings.(ABSTRACT TRUNCATED AT 250 WORDS)

The beneficial effects of implanted cardioverter defibrillator (ICD) therapy in patients with malignant ventricular tachyarrhythmias and variable degrees of left ventricular (LV) dysfunction are debated. ICD use and patient survival were examined in 128 patients with malignant ventricular arrhythmias and moderate or severe LV dys function. Group I included 64 patients with moderate LV dysfunction (LV ejection fraction of > 30%) and group H, 64 patients with severe LV dysfunction (LV ejection fracfion of ≤ 30%). Follow-up period ranged from 1 to 78 months. The two groups were similar in age, incidence of coronary artery disease and presenting arrhythmia. The mean LV ejection fraction in group I was 44%± 8% and group II was 22%± 5% (P < 0.0001). At 4 years of follow-up, 66% of patients from group I and 62% from group II (P = NS) had ICD activation for presumed ventricular tachyarrhythmia. Survival was calculated using actuarial analysis. Arrhythmic or sudden death mortality at 4 years of follow-up was 4% in group I and 7% in group II (P = NS). Cardiac mortality was for group I, 7% (P < 0.05), 12% (fP < 0,01), 15% (P < 0.01), and 15% (P < 0.01) for follow-up years 1, 2, 3, and 4, respectively. For group II, cardiac mortality was 27%, 36%, 41%, and 41% for follow-up years for 1, 2, 3, and 4, respectively. The majority of cardiac deaths in both groups was observed in the first 2 years of follow-up. However, in both groups, cardiac mortality was comparable in patients who did (users) and did not (nonusers) experience appropriate ICD shocks. Thus, the incidence of long-term ICD use is comparable in patients with moderate and severe LV dysfunction. Cardiac mortality is higher in patients with severe LV dysfunction in the first 4 years of follow-up irrespective of device use. The comparable long-term clinical outcome of ICD users and non users in patients with moderate or severe LV dysfunction can be related to elimination of arrhythmic mortality. Long-term patient survival in ICD recipients with severe LV dysfunction remains substantial even at 4 years of follow-up.

All eight stages of a stimulation protocol that used one then two extrastimuli from the right ventricular apex in sinus rhythm and three ventricular drive rates (100, 120, and 140 beats/min) were performed in 24 patients with recurrent spontaneous sustained ventricular tachycardia despite drug treatment. Twenty two of the patients had sustained a previous myocardial infarct and 18 were on long term treatment with amiodarone. Sustained (greater than 30 s) ventricular tachycardia was induced in all patients. Two extrastimuli were significantly more likely to induce sustained ventricular tachycardia than one extrastimulus, both overall and individually for the three ventricular drive rates. A ventricular drive rate of 140 beats/min was significantly more likely to induce ventricular tachycardia than ventricular drive rates of 100 and 120 beats/min which were significantly more effective than sinus rhythm. A ventricular drive rate of 140 beats/min with one or two extrastimuli induced ventricular tachycardia in 23/24 (95%) of the patients in this study. The full eight stage protocol was progressive separately for both extrastimuli and ventricular drive rate but the last two stages (ventricular drive rate of 140 beats/min with one or two extrastimuli) were as effective as the entire protocol in inducing ventricular tachycardia.

The management of cardiac arrhythmias has been revolutionized by the use of new diagnostic and therapeutic modalities. The development and advancement of both pharmacologic and nonpharmacologic therapies, particularly radiofrequency catheter ablation and new implantable devices, have resulted in better treatment, suppression, and frequently cure of otherwise recalcitrant and life-threatening cardiac arrhythmias. Furthermore, catheter ablation has also helped to better elucidate the pathophysiology of these arrhythmias. For the purpose of this chapter, the management of cardiac arrhythmias is divided into that of tachyarrhythmias and bradyarrhythmias. Tachyarrhythmias are managed by antiarrhythmic drugs, radiofrequency catheter ablation, and implantable devices. Bradyarrhythmias are treated mainly by pacemakers.