Clinical Characteristics of Patients with Arrhythmias of the Idiopathic Outflow Tract Ventricular: Age, Gender, Comorbidities, Laboratory Test Results, and Echocardiographic Parameters.

Context: Idiopathic ventricular arrhythmias (IVAs) are a spectrum of ventricular arrhythmia (VA) without structural heart disease (SHD), that includes premature ventricular contractions (PVCs) and ventricular tachycardia (VT). The clinical characteristics of patients with PVCs or VT remain unclear, including distribution of the origin of arrhythmias, age and gender differences, comorbidities, laboratory tests, and electrocardiographic parameters. Objective: The study intended to compare the clinical characteristics of the right ventricular outflow tract (RVOT)- and left ventricular outflow tract (LVOT)-VT of a large group of consecutive patients, to investigate the distribution of the origin of the arrhythmias, age and gender differences, comorbidities, laboratory-examination results, and echocardiographic parameters. Methods: The research team designed a retrospective study to collect data on the above-mentioned variables. Setting: The study occurred at the Second Hospital of Hebei Medical University in Shijiazhuang, China. Participants: Participants were 774 patients with symptomatic ventricular arrhythmias, 328 males and 446 females with the mean age of 48.6 ± 15.7 years, who underwent catheter ablation between January 2015 and January 2019. Participants were divided into the right ventricular outflow tract (RVOT) group and left ventricular outflow tract (LVOT) group, according to the different origins of their arrhythmias, with 428 participants in the RVOT group and 180 in the LVOT group. Outcome Measures: The research team collected and analyzed the data for the original sites of the IVAs; ages; genders; comorbidities; laboratory examinations, including routine blood tests, liver function, kidney function, blood lipid and potassium; and echocardiographic parameters. Results: Among the 774 participants, 76 had experienced VTs and 698 PVCs. The original site of IVAs was 2.38 times more likely to be in the RVOT than the LVOT, with the ratio for RVOT/LVOT = 2.38. IVAs usually occurred in participants between 50 and 70 years old and exhibited a decreasing incidence after 70 years of age. IVAs derived from the His bundle were more common in older participants, with a mean age of 60.4 ± 10.4 years, while IVAs derived from the fascicular were more common in younger patients, with a mean age of 36.08 ± 16.01 years. Compared with the LVOT group, the RVOT group was younger, 51.91 ± 14.65 years vs 46.95 ± 14.95 years, respectively (P < .001). PVCs in the RVOT group were more common in women, with the ratio of females/males = 2.10, and no gender difference existed in the overall incidence of IVAs in the LVOT group (P > .05). The most common cardiovascular comorbidities of outflow tract ventricular arrhythmias (OTVAs) were hypertension, coronary heart disease, and hyperlipidemia, while the most common noncardiovascular comorbidities were diabetes, ischemic stroke, and thyroid disease. The red-blood-cell counts, hemoglobin, creatinine, and gamma-glutamyl transpeptidase (GGT) of the LVOT group were higher than those from the RVOT, with P = .008, P = .009, P = .001, and P < .001, respectively. The left atrial diameter (LAD), left ventricular end-diastolic diameter (LVEDD), interventricular septal thickness (IVS), and left ventricular posterior wall thickness (LVPWT) in the LVOT group were larger than those in the RVOT group (P <.001), while the LVOT group's left ventricular ejection fraction (LVEF%) was lower than that of the RVOT group. Conclusions: The outflow tract served as the major original site of IVAs, and significant differences existed between participants in the LVOT and RVOT groups in age; gender; comorbidities; results of laboratory examinations, including red-blood-cell counts, hemoglobin, creatinine, and GGT; and echocardiographic parameters, including LVEF%, LAD, LVEDD, IVS, and LVPWT.

Risk Stratification for Sudden Cardiac Death After Myocardial Infarction.

Sudden cardiac death (SCD) accounts for ∼50% of mortality after myocardial infarction (MI). Most SCDs result from ventricular tachyarrhythmias, and the tachycardias that precipitate cardiac arrest result from multiple mechanisms. As a result, it is highly unlikely that any single test will identify all patients at risk for SCD. Current guidelines for use of implantable cardioverter-defibrillators (ICDs) to prevent SCD are based primarily on measurement of left ventricular ejection fraction (LVEF). Although reduced LVEF is associated with increased total cardiac mortality after MI, the focus of current guidelines on LVEF omits ∼50% of patients who die suddenly. In addition, there is no evidence of a mechanistic link between reduced LVEF and arrhythmias. Thus, LVEF is neither sensitive nor specific as a tool for post-MI risk stratification. Newer tests to screen for predisposition to ventricular arrhythmias and SCD examine abnormalities of ventricular repolarization, autonomic nervous system function, and electrical heterogeneity. These tests, as well as older methods such as programmed stimulation, the signal-averaged electrocardiogram, and spontaneous ventricular ectopy, do not perform well in patients with LVEF ≤30%. Recent observational studies suggest, however, that these tests may have greater utility in patients with LVEF >30%. Because SCD results from multiple mechanisms, it is likely that combinations of risk factors will prove more precise for risk stratification. Prospective trials that evaluate the performance of risk stratification schema to determine ICD use are necessary for cost-effective reduction of the incidence of SCD after MI.

Impact of the Use of Benznidazole Followed by Antioxidant Supplementation in the Prevalence of Ventricular Arrhythmias in Patients With Chronic Chagas Disease: Pilot Study.

Patients with chronic Chagas disease have a higher prevalence of premature ventricular contraction (PVC) because of immunoinflammatory response magnified by the increased oxidative stress. Thus, the sequential treatment with benznidazole (BZN) and antioxidants can reduce the prevalence of PVC. We wish to establish whether the etiological treatment of Chagas disease followed by supplementation with the antioxidant vitamins E and C decreases the prevalence of PVC in these patients. A sample of 41 patients with chronic Chagas disease at different stages of the heart disease was selected for the treatment against the causative agent using BZN (5 mg·kg·d, minimum dose 300 mg daily) for 2 months followed by supplementation with antioxidants such as vitamins E (800 UI/d) and C (500 mg/d) for 6 months. The prevalence of PVC was observed by conducting 24-hour Holter. To evaluate the oxidative status of the patients, serum markers of oxidative stress like glutathione peroxidase, superoxide dismutase, catalase, glutathione reductase, and glutathione S-transferase were measured, and also reduced glutathione, vitamin E, and markers of tissue damage like thiobarbituric acid reactive substances and protein carbonyl. A decrease in the prevalence of PVC in patients with advanced Chagas heart disease was observed (5391 vs. 1185, P = 0.0068). This reduction was followed by decrease of serum markers of oxidative stress. In patients with a lower degree of cardiac damage, the reduction on prevalence of PVC was not significant. The etiological treatment with BZN followed by supplementation with antioxidant vitamins E and C reduces episodes of PVC in patients with severe Chagas heart disease.

High prevalence of catecholamine-facilitated focal ventricular tachycardia in patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy.

BACKGROUND: Exercise-related ventricular tachycardia (VT) and high burden of premature ventricular contractions (PVCs) are common in arrhythmogenic right ventricular dysplasia/cardiomyopathy. We hypothesized that VT in arrhythmogenic right ventricular dysplasia/cardiomyopathy shows a high degree of association with the PVC at baseline. METHODS AND RESULTS: The study population included 16 consecutive arrhythmogenic right ventricular dysplasia/cardiomyopathy patients with recurrent VT who underwent catheter ablation. Median age of the patients was 27 years (range, 18-66) and 50% were men. All patients had frequent ectopy at baseline with a median PVC count of 7275 (range, 1353-19 084). During EP study, a total of 27 VTs were induced, of which 16 (59%) occurred during high-dose isoproterenol infusion. VT morphology was identical to the baseline PVCs in all the VTs induced during high-dose isoproterenol infusion. Focal ablation at the site of earliest activation and 12/12 pace map of the PVC eliminated the VT in all cases. Target site for focal ablation localized to scar border. Cumulative freedom from VT after ablation was 85.2% and 74.5% at 1 and 2 years, respectively, which was associated with a reduction in PVC count. CONCLUSIONS: We report a high degree of association between PVCs at baseline and the VTs induced during catecholamine infusion. These VTs originated from the border region of scar most commonly in the right ventricular outflow tract and right ventricle basal regions. These findings highlight the importance of catecholamine challenge and PVC mapping, which can in turn facilitate ablation of the VT in arrhythmogenic right ventricular dysplasia/cardiomyopathy.

Conduction recovery after electrical isolation of superior vena cava--prevalence and electrophysiological properties.

BACKGROUND: Superior vena cava (SVC) is an infrequent yet an important source of atrial fibrillation (AF). The data on SVC reconnection are limited. METHODS AND RESULTS: Following pulmonary vein (PV) antrum isolation for AF, SVC isolation was systemically performed under angiographic and mapping guidance using 4-mm non-irrigated tip catheter. SVC reconnection could be evaluated in 76 consecutive patients (65 ± 9 years, 59 male) who underwent repeat AF ablation after 16 ± 16 months. SVC was isolated at the 1(st), 2(nd), 3(rd) and 4(th) AF ablation procedure in 63, 7, 5 and 1 patient by 7.3 ± 3.1 radiofrequency applications. SVC reconnection was observed in 56 patients (74%). In the majority, the conduction gap was located at the anterolateral SVC-right atrium (RA) junction. After re-isolation of SVC, 2/7 patients (29%) had reconnection at the following procedure. Among 63 patients who underwent PV and SVC isolation at the initial procedure, the prevalence of reconnection for PV and that for SVC were similar (53/63, 84% vs. 46/63, 73%; P=0.129). Dissociated activity, however, was more frequently observed in the PVs than in the SVC (47/63, 73% vs. 10/63, 16%; P<0.0001). During the procedure, AF initiation from a thoracic vein was identified in 19/63 patients (30%). CONCLUSIONS: SVC reconnection is common after 1 or more previous isolation procedures undertaken for AF ablation. Its prevalence is similar to that of PV reconnection. The location of the conduction gap varies widely but is most frequently found at the anterolateral SVC-RA junction.

Association between n-3 fatty acid consumption and ventricular ectopy after myocardial infarction.

BACKGROUND: n-3 (omega-3) Fatty acids are associated with a reduced risk of cardiovascular disease; however, the relation between dietary intake of n-3 fatty acids and ventricular arrhythmias has not been investigated among acute post-myocardial infarction (AMI) patients-a group at elevated risk of malignant arrhythmias. OBJECTIVE: The objective was to examine the association between n-3 fatty acid consumption and ventricular ectopy among AMI patients. DESIGN: In 260 AMI patients, dietary intake of n-3 fatty acids was assessed by using the Harvard food-frequency questionnaire, and ventricular ectopy was estimated from 24-h electrocardiograph recordings. RESULTS: A greater intake of n-3 fatty acids (eicosapentaenoic acid + docosahexaenoic acid + docosapentaenoic acid + alpha-linolenic acid) was associated with lower ventricular ectopy (beta = -0.35, P = 0.011), and this effect remained after cardiovascular comorbidities were controlled for (beta = -0.47, P = 0.003). Higher concentrations of both marine-based (eicosapentaenoic acid + docosahexaenoic acid) (beta = -0.21, P = 0.060) and plant-based (alpha-linolenic acid) (beta = -0.33, P = 0.024) fatty acids remained associated with lower ventricular ectopy after cardiovascular comorbidities were controlled for. CONCLUSION: These findings extend existing evidence linking n-3 fatty acid consumption to a reduced risk of ventricular arrhythmias by showing that a greater intake of n-3 fatty acids may be associated with low ventricular ectopy among AMI patients.

Efficacy of n-3 polyunsaturated fatty acids according to clinical characteristics of patients with recent myocardial infarction: insights from the GISSI-Prevenzione trial.

The GISSI-Prevenzione trial established the efficacy of n-3 polyunsaturated fatty acids (PUFAs) for reducing mortality in patients after recent myocardial infarction. The generalisability of such results to clinical practice could vary according to other individual patient characteristics. We analysed the GISSI-Prevenzione database to assess whether other major risk factors, comorbidities, dietary habits, or medications could interact with the efficacy of n-3 PUFA treatment to reduce total mortality. We found no evidence that concomitant disease states, habits, or interventions altered the therapeutic benefit of n-3 PUFA consumption in survivors of recent myocardial infarction.

Idiopathic ventricular arrhythmias originating from the tricuspid annulus: Prevalence, electrocardiographic characteristics, and results of radiofrequency catheter ablation.

BACKGROUND: Idiopathic ventricular tachycardias (VTs) and premature ventricular contractions (PVCs) arising from the tricuspid annulus have been reported. OBJECTIVE: The purpose of this study was to clarify the prevalence and characteristics of VT/PVCs originating from the tricuspid annulus. METHODS: The ECG characteristics and results of radiofrequency (RF) catheter ablation were analyzed in 454 patients with idiopathic VT/PVCs. RESULTS: Thirty-eight (8%) patients had VT/PVCs arising from the tricuspid annulus: 28 VT/PVCs (74%) originated from the septal portion of the tricuspid annulus and the remaining 10 (26%) from the free wall of the tricuspid annulus. QRS duration and Q-wave amplitude in each of leads V1-V3 were greater in VT/PVCs arising from the free wall of the tricuspid annulus than those from the septum of the tricuspid annulus (all P < .01). "Notching" of the QRS complex was observed more often in VT/PVCs arising from the free wall of the tricuspid annulus than those from the septum of the tricuspid annulus (P < .01). A Q wave in lead V1 was observed more often in VT/PVCs arising from the septum of the tricuspid annulus than those from the free wall of the tricuspid annulus (P < .005). R-wave transition occurred beyond lead V3 more often in VT/PVCs arising from the free wall of the tricuspid annulus than those from the septum of the tricuspid annulus (P < .005). RF catheter ablation eliminated 90% of the VT/PVCs arising from the free wall of the tricuspid annulus but only 57% of the VT/PVCs arising from septum of the tricuspid annulus. CONCLUSION: Idiopathic VT/PVCs arising from tricuspid annulus are not rare, and the detailed origin can be determined by ECG analysis. The preferential site of origin was the septum but also could be the free wall of the tricuspid annulus.

Quality of life and cost for patients with premature ventricular contractions by radiofrequency catheter ablation.

OBJECTIVE: To evaluate the quality of life (QoL), health-care resource utilization, and cost for the patients with premature ventricular contractions (PVCs) by radiofrequency catheter ablation (RFCA). METHODS: RFCA was performed in 58 patients with symptomatic PVCs that were refractory/easy to medication. A 24-hour ambulatory electrocardiographic monitoring, QoL, health-care resources utilization, and cost were assessed at a screening visit and 3 and 12 months after RFCA. RESULTS: RFCA was successfully performed in 56 patients (96.6%). This resulted in a significant improvement in the QoL at 3 and 12 months after the procedure. There were no major complications related to the procedure. Nine patients (15.5%) had residual arrhythmia. Seven of them underwent repeated ablation with successful results. It also improved the QoL and reduced health-care resource utilization and cost. CONCLUSIONS: RFCA is a safe and effective treatment for PVCs, and it is a viable alternative to drugs in the presence of disabling symptoms.

Idiopathic ventricular arrhythmia arising from the mitral annulus: a distinct subgroup of idiopathic ventricular arrhythmias.

OBJECTIVES: We sought to clarify the prevalence and characteristics of idiopathic ventricular tachycardia or premature ventricular contraction originating from the mitral annulus (MAVT/PVC). BACKGROUND: Recent case reports have presented patients with MAVT/PVC. METHODS: Electrocardiographic (ECG) characteristics and the results of electrophysiologic investigation and radiofrequency catheter ablation (RFCA) were analyzed in 352 patients with symptomatic idiopathic ventricular tachycardia (IVT)/premature ventricular contraction (PVC). RESULTS: Nineteen cases of IVT/PVC (5%) represented MAVT/PVC. Of these, 11 (58%) originated from the anterolateral portion of the mitral annulus (AL-MAVT/PVC), and 2 (11%) arose from the posterior portion (Pos-MAVT/PVC). The remaining six cases of MAVT/PVC (31%) had posteroseptal origin (PS-MAVT/PVC). In all patients, an S-wave was present in lead V(6). The QRS polarity in inferior leads and leads I and aVL was useful for differentiating AL-MAVT/PVC from Pos-MAVT/PVC or PS-MAVT/PVC. The Pos-MAVT/PVC had an Rs pattern in lead I and an R pattern in lead V(1), whereas PS-MAVT/PVC invariably had an R pattern in lead I and a negative QRS component in lead V(1). The AL-MAVT/PVC and Pos-MAVT/PVC showed a longer QRS duration than the PS-MAVT/PVC (p < 0.001), and all had late-phase "notching" of the QRS complex in inferior leads. In all patients, RFCA eliminated MAVT/PVC, with no recurrences during follow-up for 21 +/- 15 months. CONCLUSIONS: Mitral annular VT/PVC is a rare but distinct subgroup of IVT/PVC. MAVT/PVC origin could be determined by ECG analysis. The AL and PS sites of the MA were preferential.

Effects of n-3 fatty acids from fish on premature ventricular complexes and heart rate in humans.

BACKGROUND: A large body of evidence suggests that n-3 fatty acids from fish prevent fatal heart disease. They may be an effective and safe alternative to drug treatment for reducing the risk of arrhythmia and sudden cardiac death. OBJECTIVE: We investigated the effect of n-3 fatty acids on heart rate and premature ventricular complexes (PVCs), a common form of arrhythmia that may trigger arrhythmias that are more life-threatening. DESIGN: Patients (n=84) with >or=1440 PVCs/24 h in a previous Holter recording were randomly assigned to receive 1.5 g/d of either n-3 fatty acids or placebo. Two 24-h Holter recordings were made at baseline, and 2 were made after an intervention of approximately 14 wk. RESULTS: Treatment did not significantly affect the number of PVCs. The number decreased in the fish-oil group by 867/24 h more than it decreased in placebo group (95% CI: -3187, 1453). However, the mean 24-h heart rate was significantly affected, decreasing in the fish-oil group by a mean of 2.1 beats/min more than it decreased in the placebo group (95% CI: -3.9, -0.3). CONCLUSIONS: Supplementation with 1.5 g n-3 fatty acids/d from fish does not substantially suppress the number of PVCs in a patient population with frequent PVCs. However, n-3 fatty acids decreased heart rate by 2.1 beats/min, a significant decrease that predicts a lower risk of sudden death.

Heart rate turbulence after ventricular and atrial premature beats in subjects without structural heart disease.

INTRODUCTION: Studies assessing heart rate (HR) behavior after premature beats have focused on HR responses to ventricular premature beats (VBPs), but there is less information of HR behavior after atrial premature beats (APBs). METHODS AND RESULTS: HR turbulence after VPBs and APBs was first measured in response to ambient APBs and VPBs occurring during 24-hour ambulatory ECG recordings in 29 subjects without structural heart disease, and in response to programmed atrial (AE) and ventricular extrastimuli (VE) in 6 subjects undergoing electrophysiologic (EP) examination. Turbulence onset (TO) was more negative (-2.3 +/- 3.2% vs -0.9 +/- 2.8%, P < 0.01) and turbulence slope (TS) was steeper (11 +/- 11 vs 5.1 +/- 4.1 msec/R-R interval, P < 0.05) after VPBs than APBs. Compared to VPBs, the acceleration of HR after APBs was delayed by one beat, and APBs were associated with a short R-R interval preceding the APB, resulting in a blunted TO. Studies of patients undergoing an EP test confirmed the one-beat delay of HR acceleration and the blunted TO after programmed AE compared to VE (P < 0.05). TO and TS after VPBs were related to baroreflex sensitivity. TO also was related to 24-hour standard deviation of N-N intervals (SDNN). However, the TO or TS following APBs was not related to either SDNN or baroreflex sensitivity. CONCLUSION: HR behavior is different in response to APBs and VBPs among subjects without structural heart disease. Different definitions and calculation formulas should be used in the analysis of HR turbulence after APBs and VPBs.

Natural history of Brugada syndrome: the prognostic value of programmed electrical stimulation of the heart.

INTRODUCTION: The prognostic value of electrophysiologic studies in individuals with the syndrome of right bundle branch block and ST segment elevation in precordial leads V1 to V3 (Brugada syndrome) remains controversial. Our previous data from 252 individuals with the syndrome suggested that programmed ventricular stimulation had a good overall accuracy to predict events. However, studies from independent investigators questioned our results. We report here the largest population with Brugada syndrome ever studied by programmed electrical stimulation of the heart. METHODS AND RESULTS: Four hundred forty-three individuals with an ECG diagnostic of Brugada syndrome were studied by programmed electrical stimulation of the heart. The diagnosis was made because of the classic ECG showing a coved-type ST segment elevation in precordial leads V1 to V3. Of the 443 individuals, 180 had developed spontaneous symptoms (syncope or aborted sudden cardiac death) and 263 were asymptomatic at the time the diagnosis was made. The ventricular stimulation protocol included a minimum of two basic pacing cycle lengths with two ventricular premature beats from the right ventricular apex. A sustained ventricular arrhythmia was induced in 217 cases (49%). Symptomatic patients were more frequently inducible [126/180 (70%)] than asymptomatic individuals [91/263 (34%); P = 0.0001]. Males were more frequently inducible than females (54% vs 32%, P < 0.0001). Inducible individuals had a longer HV interval than noninducible patients (50 +/- 12 msec vs 46 +/- 10 msec, P < 0.002). HV interval and number of premature beats needed to induce VF were not related to outcome. Inducibility was statistically a powerful predictor of arrhythmic events during follow-up. Sixty of 217 inducible patients (28%) had spontaneous ventricular fibrillation compared with 5 of 221 noninducible patients (2%; P = 0.0001). CONCLUSION: Inducibility of sustained ventricular arrhythmias during programmed ventricular stimulation of the heart is a good predictor of outcome in Brugada syndrome.