A score model to predict risk of events in patients with Brugada Syndrome.

AIMS: Risk stratification in Brugada Syndrome (BS) remains challenging. Arrhythmic events can occur life-long and studies with long follow-ups are sparse. The aim of our study was to investigate long-term prognosis and risk stratification of BS patients. METHODS AND RESULTS: A single centre consecutive cohort of 400 BS patients was included and analysed. Mean age was 41.1 years, 78 patients (19.5%) had a spontaneous type I electrocardiogram (ECG). Clinical presentation was aborted sudden cardiac death (SCD) in 20 patients (5.0%), syncope in 111 (27.8%) and asymptomatic in 269 (67.3%). Familial antecedents of SCD were found in 184 individuals (46.0%), in 31 (7.8%) occurred in first-degree relatives younger than 35 years. An implantable cardioverter defibrillator (ICD) was placed in 176 (44.0%). During a mean follow-up of 80.7 months, 34 arrhythmic events occurred (event rate: 1.4% year). Variables significantly associated to events were: presentation as aborted SCD (Hazard risk [HR] 20.0), syncope (HR 3.7), spontaneous type I (HR 2.7), male gender (HR 2.7), early SCD in first-degree relatives (HR 2.9), SND (HR 5.0), inducible VA (HR 4.7) and proband status (HR 2.1). A score including ECG pattern, early familial SCD antecedents, inducible electrophysiological study, presentation as syncope or as aborted SCD and SND had a predictive performance of 0.82. A score greater than 2 conferred a 5-year event probability of 9.2%. CONCLUSIONS: BS patients remain at risk many years after diagnosis. Early SCD in first-degree relatives and SND are risk factors for arrhythmic events. A simple risk score might help in the stratification and management of BS patients.

Prolonged intra-myocardial growth hormone administration ameliorates post-infarction electrophysiologic remodeling in rats.

Experimental studies indicate improved ventricular function after treatment with growth hormone (GH) post-myocardial infarction, but its effect on arrhythmogenesis is unknown. Here, we assessed the medium-term electrophysiologic remodeling after intra-myocardial GH administration in (n = 33) rats. GH was released from an alginate scaffold, injected around the ischemic myocardium after coronary ligation. Two weeks thereafter, ventricular tachyarrhythmias were induced by programmed electrical stimulation. Monophasic action potentials were recorded from the infarct border, coupled with evaluation of electrical conduction and repolarization from a multi-electrode array. The arrhythmia score was lower in GH-treated rats than in alginate-treated rats or controls. The shape and the duration of the action potential at the infarct border were preserved, and repolarization-dispersion was attenuated after GH; moreover, voltage rise was higher and activation delay was shorter. GH normalized also right ventricular parameters. Intra-myocardial GH preserved electrical conduction and repolarization-dispersion at the infarct border and decreased the incidence of induced tachyarrhythmias in rats post-ligation. The long-term antiarrhythmic potential of GH merits further study.

Intra-myocardial growth hormone administration ameliorates arrhythmogenesis during ischemia-reperfusion in rats.

Growth hormone, currently under evaluation for the prevention of left ventricular remodeling post-myocardial infarction, displays antiarrhythmic properties in the acute setting. However, it is uncertain whether these actions are retained after ischemia/reperfusion. Using implanted telemetry transmitters, we examined the effects of prolonged, intra-myocardial growth hormone administration in conscious rats. During a 24-h observation period, ventricular tachyarrhythmias and sympathetic activation were attenuated in treated rats, whereas infarct-size was unchanged. These findings call for further study on the antiarrhythmic effects of growth hormone and on the underlying mechanisms.

Single 3-Minute versus Double 4-Minute Freeze Strategy for Second-Generation Cryoballoon Ablation: A Single-Center Experience.

INTRODUCTION: Second-generation cryoballoon (CB-Adv) ablation is highly effective in achieving pulmonary vein isolation (PVI) with promising mid-term clinical outcome. However, the ideal freezing strategy is still under debate. The aim of this study was to assess the efficacy of a single 3-minute approach compared to the conventional 4-minute plus bonus application using CB-Adv. METHODS AND RESULTS: One hundred and sixty patients (67% male; mean age 58.0 ± 13.3 years) underwent PVI using CB-Adv for paroxysmal atrial fibrillation (PAF). Among 160 patients, 80 received a single 3-minute approach (3-mns group), while the remaining 80 conventional 4-minute plus bonus-freeze (4-mns group). Mean procedure and fluoroscopy times were 90.6 ± 15.8 and 18.3 ± 6.9 in the 4-mns group, 75.2 ± 17.1 and 13.5 ± 8.7 in the 3-mns group (P < 0.001, respectively). First-freeze isolation rate was 91.6% in the 4- versus 90.6% in the 3-mns group (P = 0.78). Persistent phrenic nerve palsy (PNP) occurred in 6/80 (3.5%) in the 4-mns group and 4/80 in the 3-mns group (P = 0.75). The overall freedom from ATas 2 years after the procedure was 78.1% (125/160): 77.5% (62/80 patients) in the 3-mns and 78.8% (63/80 patients) in the 4-mns group (P = 0.82). In multivariate analysis, time to PVI and nadir temperature independently predicted ATa recurrences (P < 0.001). CONCLUSIONS: CB-Adv ablation for PAF is highly effective, resulting in 78% 2-year freedom from arrhythmic recurrences. A "single 3-minute strategy" showed equal efficacy as compared to the conventional 4-minute plus bonus freeze approach at 2-year follow-up, providing shorter procedure and fluoroscopy time. Nadir temperature and time to PVI were predictors of arrhythmic recurrences. "Bonus-freeze" strategy might be unnecessary.

Electrophysiological findings following pulmonary vein isolation using radiofrequency catheter guided by contact-force and second-generation cryoballoon: lessons from repeat ablation procedures.

AIMS: To assess the incidence of late pulmonary vein (PV) reconnection following index PV isolation (PVI) procedure initially achieved with radiofrequency contact-force catheter ablation (CFCA) and second-generation cryoballoon ablation (CB-AdvA). METHODS AND RESULTS: A total of 56 consecutive patients (41 male, 73.2%; mean age 60.8 ± 11.8 years) underwent a repeat ablation because of recurrent atrial tachyarrhythmias (ATas) after index PVI achieved with CFCA (30 patients) or CB-AdvA (26 patients). All repeat procedures were performed by the means of CFCA. In the CFCA group, among 119 PVs, 43 (36.1%) showed conduction gaps in 24 patients (1.8 per patient), whereas in the CB-AdvA group among 103 veins, 21 (20.4%) showed a PV reconnection in 18 patients (1.2 per patient) (P = 0.01). The left superior pulmonary vein was less frequently reconnected following CB-AdvA when compared with CFCA (2/25, 8% vs. 11/29, 37.9%; P = 0.01). In the CFCA group, the mean CF per-vein was lower in reconnecting veins when compared with those persistently isolated (10.9 ± 2.7 vs. 18.6 ± 3.1 g; P < 0.001). In the CB-AdvA group, late PV reconnection was associated with warmer nadir temperature (-48.9 ± 5.1 vs. -51.2 ± 4.7°C; P = 0.05) and longer time-to-isolation (71.1 ± 20.2 vs. 50.2 ± 32.9 s; P = 0.03). CONCLUSION: The rate of late PV reconnection is significantly lower following CB-AdvA when compared with CFCA as index procedure. Lower CF values and warmer nadir temperature with longer time to effect were more frequently associated with PV reconnections in the setting of CFCA and CB-AdvA.

Prevalence and Clinical Impact of Early Repolarization Pattern and QRS-Fragmentation in High-Risk Patients With Brugada Syndrome.

BACKGROUND: The phenotypic heterogeneity of Brugada syndrome (BrS) can lead some patients to show an additional inferolateral early repolarization pattern (ERP), or fragmented QRS (f-QRS). The aim of the study was to investigate the prevalence and clinical impact of f-QRS, ERP or combined f-QRS/ERP in high-risk patients with BrS. METHODS AND RESULTS: Patients with spontaneous or drug-induced BrS and an indication to receive an implantable cardioverter-defibrillator (ICD) were considered eligible for this study. From 1992 to 2012, a total of 176 consecutive patients with BrS underwent ICD implantation. Among them, 48 subjects (27.3%) presented with additional depolarization and/or repolarization abnormalities. f-QRS was found in 29 (16.5%), ERP in 15 (8.5%), and combined f-QRS/ERP in 4 patients (2.3%). After a mean follow-up of 95.2±51.9 months, spontaneous sustained ventricular arrhythmias were documented in 8 patients (16.7%). No significant difference was found in the rate of appropriate shocks between patients presenting with f-QRS or ERP and those without abnormalities. Patients with both f-QRS and ERP had a significantly higher rate of appropriate shocks (HR: 4.1; 95% CI: 1.1-19.7; P=0.04). CONCLUSIONS: Fragmented QRS and ERP are common ECG findings in high-risk BrS patients, occurring in up to 27% of cases. When combined, f-QRS and ERP confer a higher risk of appropriate ICD interventions during a very long-term follow-up. (Circ J 2016; 80: 2109-2116).

Circumferential pulmonary vein isolation as index procedure for persistent atrial fibrillation: a comparison between radiofrequency catheter ablation and second-generation cryoballoon ablation.

AIMS: To assess the 1 year efficacy of pulmonary vein isolation (PVI) as index procedure for persistent atrial fibrillation (PersAF) comparing conventional radiofrequency irrigated-tip catheter ablation (RFCA) using contact-force technology and ablation using the second-generation cryoballoon (CB-AdvA). METHODS AND RESULTS: One hundred consecutive patients (74 male, 74%; mean age 62.4 ± 9.6 years) with drug-refractory PersAF undergoing PVI using RFCA and CB-AdvA were enrolled. Follow-up was based on outpatient clinic visits including Holter-electrocardiograms. Recurrence of atrial tachyarrhythmias (ATas) was defined as a symptomatic or documented episode >30 s. Among 100 patients, 50 underwent RFCA whereas 50 CB-AdvA. Mean procedure and fluoroscopy times were 90.5 ± 41.7 vs. 140.2 ± 46.9 min and 14.5 ± 6.6 vs. 19.8 ± 6.8 min in the CB-Adv and in the RFCA group, respectively (P < 0.01). At 1 year follow-up, after a 3 months blanking period (BP), freedom from ATas off-drugs after a single procedure was 60% (28/50 patients) in the CB-Adv and 56% (27/50 patients) in the RFCA group (P = 0.71). Multivariate analysis demonstrated that PersAF duration (P = 0.01) and relapses during BP (P = 0.02) were independent predictors of ATa recurrences following the index procedure. CONCLUSION: Freedom from ATas following PersAF ablation with RFCA and CB-Adv is comparable at 1 year follow-up after a single procedure. Ablation with the CB-Adv is associated with shorter procedure time and radiation exposure as compared with RFCA. Atrial tachyarrhythmias occurrence during BP and longer time of PersAF seem to be significant predictors of arrhythmia recurrences after the index procedure.

Persistence of Phrenic Nerve Palsy Following 28-mm Cryoballoon Ablation: A Four-Year Single Center Experience.

BACKGROUND: Phrenic nerve palsy (PNP) is the most frequently observed complication in the setting of cryoballoon (CB) ablation (Arctic Front, Medtronic Inc., Minneapolis, MN, USA). Although, usually transient, resolving before the end of the procedure, persistent PNP (not resolving before the end of procedure) can occur. Literature on persistent PNP after second generation CB ablation is relatively sparse. METHODS: A total of 316 consecutive patients having undergone large 28-mm CB ablation as index procedure in the Heart Rhythm Management Center, UZ Brussels, Belgium, from January 2009 to December 2013 were retrospectively reviewed for the study. Of these 117 patients were treated with the first generation CB (CB1) and 199 patients with the second generation CB (CB2). RESULTS: PNP occurred in 10% of the total population. Persistent PNP was only observed following CB2 ablation which occurred in 4.5% of the group. At a mean follow-up of 11 months, diaphragmatic contraction in persistent PNP patients resumed in 78% (7/9) of the patients. In a final follow-up at 5 and 20 months, PNP persisted in two patients, respectively. PNP during ablation in the right inferior pulmonary vein was only observed in the CB2 group. No predictors of persistency of PNP were observed. CONCLUSION: Persistence of PNP only occurred in the CB2 group in 4.5% of patients. The majority of patients with persistent PNP were asymptomatic. In most of the patients having persistent PNP after ablation, complete phrenic nerve function resumed during follow-up (78%).

Clinical characteristics, management, and prognosis of elderly patients with Brugada syndrome.

BACKGROUND: The clinical course and prognosis of Brugada syndrome (BS) in the elderly is unknown. The purpose of this study was to investigate the clinical characteristics, management, and prognosis of BS in an elderly population. METHODS AND RESULTS: A total of 437 patients with BS were included in this study. Patients were categorized in 2 groups according to the age at the time of diagnosis: <60 years (N = 363) and ≥60 years (N = 74). Moreover, an elderly patients' subgroup analysis was performed between patients with an age between 60 and 70 years (N = 49) and subjects older than 70 years (N = 25). Among elderly patients (50% male, mean age: 67 ± 6 years), family history of sudden death (SD) and induction of sustained ventricular arrhythmias during programmed ventricular stimulation were less frequent as compared to younger patients. Two patients (3%) had a previous episode of aborted SD. Elderly patients with BS presented more frequently with ECG conduction disturbances or previous transient advanced atrioventricular block as compared to younger patients. Of the elderly patients, 42% underwent implantable cardioverter defibrillator implantation and 7% received a pacemaker. After a mean follow-up time of 54 ± 18 months, none of the elderly patients with BS older than 70 years experienced documented life-threating ventricular arrhythmias. Family screening was performed in 58 family members and a BS diagnosis was confirmed in 49%. CONCLUSION: The clinical features and the benign prognosis of BS patients older than 70 years likely identify a lower risk category of patients as compared to younger individuals. The device-guided management in this setting remains individualized and sometimes controversial. Moreover, BS diagnosis in the elderly should not be missed, mainly due to the clinical impact on the family of elderly patients.

One year incidence of iatrogenic atrial septal defect after cryoballoon ablation for atrial fibrillation.

INTRODUCTION: Pulmonary vein (PV) isolation by means of cryoballoon (CB) technology is an effective treatment for symptomatic paroxysmal atrial fibrillation (AF) refractory to antiarrhythmic drug therapy. The CB requires a 15F transseptal sheath that may lead to the creation of a iatrogenic atrial septal defect (IASD). METHODS AND RESULTS: Individuals having undergone PV isolation by the means of CB ablation and a subsequent transesophageal echocardiography (TEE) examination during postablation follow-up were consecutively included. Thirty-nine patients formed the study group (31 male, 76.9%; mean age 57.4 ± 13.7 years). IASD was present in 8 (20%) of them after a mean follow-up time of 11.7 months. Mean diameter of the defect was 0.57 cm × 0.48 cm; only left to right shunt was observed. No adverse events were recorded in these patients during the follow-up. CONCLUSION: IASD after CB ablation of AF is present in up to 20% of patients after 1 year. Although no adverse clinical events were recorded in patients with persistence of IASD, this complication should not be underestimated and systematic echocardiographic examinations might be advised at regular intervals in the follow-up period after CB. Further studies with larger population and follow-up might be required to confirm our findings.

Spontaneous and adenosine-induced pulmonary vein reconnection after cryoballoon ablation with the second-generation device.

INTRODUCTION: Longer observational time and adenosine challenge have proven to be able to detect pulmonary vein (PV) reconnections. The aim of this study was to assess incidence of spontaneous and adenosine-induced PV reconnection after ablation with second-generation cryoballoon (CB-Adv). METHODS AND RESULTS: Fifty consecutive patients (76% male, mean age 60.5 ± 11.9 years) having undergone PV isolation (PVI) using the CB-Adv were enrolled. After isolation, reconnections were evaluated using the Achieve catheter over 30 minutes observation and adenosine administration during isoproterenol infusion (adenosine challenge). Among 200 PVs, isolation was achieved in 190 (95%) during the first application. Lower nadir temperature and longer rewarming time were associated with successful PVI (P = 0.02 and 0.04). Spontaneous (4 veins) and adenosine-induced (4 veins) PV reconnections occurred in the 4% of initially isolated veins (8 veins) in 6 patients (12%). At receiver-operator curve analysis, nadir temperature <-51 °C and rewarming time >28 seconds identified absence of reconnections (sensitivity 100% and 87%, area under the curve 0.75 and 0.72). Patients with right-sided early branching frequently experienced reconnections (P < 0.01). After a mean follow-up of 7.0 ± 1.7 months, 86% of patients were free from atrial fibrillation. None of those with PV reconnections experienced recurrences. CONCLUSIONS: The incidence of spontaneous and adenosine-induced PV reconnection following ablation with the novel CB-Adv is very low occurring in 4% of initially isolated veins. Nadir temperature <-51 °C and rewarming time >28 seconds identified absence of acute reconnections, thus avoiding prolonged waiting time and adenosine challenge in such cases.

One-year follow-up after single procedure Cryoballoon ablation: a comparison between the first and second generation balloon.

BACKGROUND: With respect to the first generation Cryoballoon (CB), the second generation (Cryoballoon Advance [CB-A], Medtronic, Minneapolis, MN, USA) was designed with technical modifications resulting in a larger and more uniform zone of freezing on the balloon's surface aiming at procedural outcome improvement in the setting of atrial fibrillation (AF) ablation. However, a comparison between both technologies on a midterm follow-up is missing in today's literature. METHODS: A total of 100 patients (the last 50 patients with the first generation CB and the first 50 patients with the second generation CB-A upon its inception in our center) having undergone a single CB ablation for paroxysmal AF (PAF) and having completed a 12-month follow-up, were consecutively included in our study. Freedom from AF off-antiarrhythmic drugs (AADs) after a single procedure was 78% (39/50) in CB-A and 58% (29/50) in the CB group (P = 0.03) during the whole follow-up duration. Considering a blanking period of 3 months, freedom from AF off-AAD was achieved in 84% (42/50) in CB-A, while 66% (33/50) were free from recurrence in the CB group (P = 0.038). Right phrenic nerve palsy (PNP) occurred in 8 patients (16%) in CB-A group and in 4 patients (8%) in the CB group. CONCLUSION: Freedom from AF on 12 months follow-up was significantly higher in the CB-A group with respect to the first generation device. The most frequent complication observed was PNP.

Pulmonary vein isolation in patients with Brugada syndrome and atrial fibrillation: a 2-year follow-up.

AIMS: Pharmacological treatment of atrial fibrillation (AF) in the setting of Brugada syndrome (BS) might be challenging as many antiarrhythmic drugs (AADs) with sodium channel blocking properties might expose the patients to the development of ventricular arrhythmias. Moreover, patients with BS and implantable cardioverter-defibrillator (ICD) might experience inappropriate shocks because of AF with rapid ventricular response. The role of pulmonary vein isolation (PVI) in patients with BS and recurrent episodes of AF has not been established yet. In this study, we analysed the outcome of PVI using radiofrequency energy or cryoballoon (CB) ablation at 2 years follow-up. METHODS AND RESULTS: Consecutive patients with BS having undergone PVI for drug-resistant paroxysmal AF were eligible for this study. Nine patients (three males; mean age: 52 ± 26 years) were included. Six patients (67%) had an ICD implanted of whom three had inappropriate shocks because of rapid AF. At a mean 22.1 ± 6.4 months follow-up, six patients (67%) were free of AF without AADs. None of the three patients who had experienced inappropriate ICD interventions for AF had further ICD shocks after ablation. CONCLUSION: In our study PVI can be an effective and safe procedure to treat patients with BS and recurrent episodes of paroxysmal AF.

Comparison of the patient-activated event recording system vs. traditional 24 h Holter electrocardiography in individuals with paroxysmal palpitations or dizziness.

AIMS: Electrocardiographic documentation of symptomatic episodes of palpitations by means of traditional methods such as 24 h Holter monitoring (HM) or loop recorders is challenging. Patient-activated electrocardiography (ECG) recorders have been proved to be a useful tool in the diagnosis of arrhythmias in these patients. However, no comparison studies between the two techniques have been conducted. The aim of this study was to compare the diagnostic value of Holter ECG and a patient-activated event recorder (OMRON portable HeartScan ECG Monitor(®)) (HeartScan) in the detection of arrhythmias in patients with paroxysmal palpitations or dizziness suggestive of cardiac arrhythmias. METHODS AND RESULTS: Patients with paroxysmal palpitations or dizziness were eligible for this study. All patients underwent an HM for 24 h and a 15-day HeartScan after the HM. Six hundred and twenty-five patients (48% male, mean age: 37 ± 11 years) were included in the study. All patients present with normal heart structure, normal baseline 12-lead ECG, and normal echocardiogram. Indications for ECG monitoring were palpitations in 577 patients (92.3%) and dizziness in 48 (7.7%). Holter monitoring offered a clinical diagnosis in 11 patients (1.8%). Conversely, HeartScan diagnosed the clinical arrhythmia in 558 individuals (89%). Detection of symptoms-related arrhythmias by means of HeartScan was significantly higher when compared with HM (P < 0.01). CONCLUSION: The studied system proved to be an efficient event recorder providing the diagnosis of the clinical arrhythmia in 89% of patients with paroxysmal palpitations or dizziness. Further studies are needed to confirm our results.

Second-generation cryoballoon ablation for paroxysmal atrial fibrillation: 1-year follow-up.

BACKGROUND: The novel cryoballoon Advance (CB-A) has proven to achieve significantly lower temperatures and faster pulmonary vein isolation (PVI) times in comparison with the first-generation device. Although acutely very effective, to the best of our knowledge, data on mid-term clinical follow-up is lacking. AIMS: The aim of the study was to analyse the freedom from recurrence of atrial fibrillation (AF) on a 1-year follow-up period, in a series of consecutive patients having undergone PVI with the CB-A for paroxysmal AF (PAF). METHODS AND RESULTS: Forty-two patients [30 male (71%); mean age: 57.9 ± 21.1 years] were included. All patients underwent a procedure with the large 28 mm CB-A. A total 168 PVs were depicted on the pre-procedural computed tomography scan. All PVs (100%) could be isolated with the CB only. The freedom from AF off-antiarrhythmic drug treatment after a single procedure was 78% of patients at a mean 11.6 ± 2.0 months follow-up. If considering a blanking period (BP) of 3 months, success rate was 83%. Phrenic nerve palsy (PNP) was the most frequent complication occurring in 19% of individuals. CONCLUSION: The CB-A is very effective in producing PVI and affords freedom from AF at 12 months follow-up in 83% of patients affected by drug-resistant PAF following a 3-month BP. The most frequent complication observed was PNP which occurred in 19% of patients. All PNP reverted during follow-up.

Prevalence and electrocardiographic characteristics of early repolarization pattern in young teen athletes.

INTRODUCTION: Early repolarization (ERP) is a common electrocardiographic finding. Its potential to cause cardiac arrhythmias has been hypothesized from experimental studies, but it is not known whether there is a clinical association with sudden cardiac arrest. METHODS: 122 subjects (100% males; mean age: 13.5 +/- 2.7 years) were included from a local youth soccer team in Belgium. All subjects underwent physical examination and a 12-lead ECG was taken. The main objective of the study was to evaluate early repolarization patterns and to determine its prevalence. RESULTS: Of the 122 included subjects, 1 subject with Coumel tachycardia was excluded.The overall prevalence of ERP in our study population was 36%, with 9.1% in the inferior leads, 8.2% in the lateral leads and 18.2% both leads. A family history of sudden cardiac death (SCD) was not higher in the group of ERP (N=3; 6.8%) compared to the non-ERP group (N = 4; 5.2%) (P = 0.713). Interestingly, incomplete right bundle-branch block (IRBBB) was significantly lower among all subjects with ERP (N = 15; 34.1%), compared to those without ERP (N = 49; 63%) (P < 0.002). CONCLUSION: ERP is a common finding in young teen athletes. In this population global ERP (both inferior and lateral) is more common than isolated inferior or lateral ERP. Young age might be a contributing factor in causing a more diffuse repolarization abnormality.

Repeat procedure using radiofrequency energy for recurrence of atrial fibrillation after initial cryoballoon ablation: a 2-year follow-up.

AIMS: The ideal energy source needed to perform 're-isolation' of the pulmonary veins (PVs) during a repeat procedure for recurrence of paroxysmal atrial fibrillation (AF) has not been established yet. In this study we analysed the outcome of repeat procedure using radiofrequency (RF) energy after initial cryoballoon (CB) ablation at 2-year follow-up. METHODS AND RESULTS: Consecutive patients having undergone PVs isolation as repeat procedure for recurrent AF after an initial CB ablation were eligible for this study. Twenty-nine patients (22 male 76%, mean age: 55 ± 17 years) were included. Mean time to repeat ablation was 12 ± 7 months. Recovered PV conduction could be documented in a mean 2.45 ± 0.7 veins in each patient. At mean 20.2 ± 10.7 months follow-up, a total of 16 patients (55%) were free of AF at without antiarrhythmic drugs (AADs). An adjunctive 31% was AF free with previously ineffective AADs. A major complication with no permanent clinical sequelae occurred only in one patient. CONCLUSION: Repeat RF ablation following CB in case of AF recurrence is effective and safe.

Determinants of pulmonary hypertension in patients with Beta-thalassemia major and normal ventricular function.

BACKGROUND/AIMS: We sought to define the incidence and predictive factors of pulmonary hypertension in ß-thalassemia major. METHODS: We studied 27 consecutive patients (19 male, 38 ± 9 years of age) with ß-thalassemia major. All the patients had normal (left and right) ventricular (systolic and diastolic) function and underwent echocardiographic assessment of pulmonary artery systolic pressure. Univariate regression and discriminant function analyses were used to identify predictive factors of pulmonary hypertension. RESULTS: Pulmonary hypertension was observed in 18.5% of the patients, but clinically significant disease was detected in only 3.7%. A total of 14 (51.8%) patients had been receiving a combined administration of deferoxamine and deferiprone for 7.0 ± 1.3 years. Amidst a large number of variables examined, ferritin levels and delayed onset of chelation therapy were the only predictors of pulmonary hypertension. CONCLUSION: Pulmonary hypertension in ß-thalassemia major is relatively infrequent and generally mild due to improved chelation therapy. The role of hemochromatosis in pulmonary hypertension development merits further study.

Chronic skeletal muscle ischemia preserves coronary flow in the ischemic rat heart.

Chronic skeletal muscle ischemia confers cytoprotection to the ventricular myocardium during infarction, but the underlying mechanisms remain unclear. Although neovascularization in the left ventricular myocardium has been proposed as a possible mechanism, the functional capacity of such vessels has not been studied. We examined the effects of chronic limb ischemia on infarct size, coronary blood flow, and left ventricular function after ischemia-reperfusion. Hindlimb ischemia was induced in 65 Wistar rats by excision of the left femoral artery, whereas 65 rats were sham operated. After 4 wk, myocardial infarction was generated by permanent coronary artery ligation. Infarct size was measured 24 h postligation. Left ventricular function was evaluated in isolated hearts after ischemia-reperfusion, 4 wk after limb ischemia. Neovascularization was assessed by immunohistochemistry, and coronary flow was measured under maximum vasodilatation at different perfusion pressures before and after coronary ligation. Infarct size was smaller after limb ischemia compared with controls (24.4 ± 8.1% vs. 46.2 ± 9.5% of the ventricle and 47.6 ± 8.7% vs. 80.1 ± 9.3% of the ischemic area, respectively). Indexes of left ventricular function at the end of reperfusion (divided by baseline values) were improved after limb ischemia (developed pressure: 0.68 ± 0.06 vs. 0.59 ± 0.05, P = 0.008; maximum +dP/dt: 0.70 ± 0.08 vs. 0.59 ± 0.04, P = 0.004; and maximum -dP/dt: 0.86 ± 0.14 vs. 0.72 ± 0.10, P = 0.041). Coronary vessel density was markedly higher (P = 0.00021) in limb ischemic rats. In contrast to controls (F = 5.65, P = 0.00182), where coronary flow decreased, it remained unchanged (F = 1.36, P = 0.28) after ligation in limb ischemic rats. In conclusion, chronic hindlimb ischemia decreases infarct size and attenuates left ventricular dysfunction by increasing coronary collateral vessel density and blood flow.

Endothelin-B receptors and ventricular arrhythmogenesis in the rat model of acute myocardial infarction.

The arrhythmogenic effects of endothelin-1 (ET-1) are mediated via ETA-receptors, but the role of ETB-receptors is unclear. We examined the pathophysiologic role of ETB-receptors on ventricular tachyarrhythmias (VT/VF) during myocardial infarction (MI). MI was induced by coronary ligation in two animal groups, namely in wild-type (n = 63) and in ETB-receptor-deficient (n = 61) rats. Using a telemetry recorder, VT/VF episodes were evaluated during phase I (the 1st hour) and phase II (2-24 h) post-MI, with and without prior beta-blockade. Action potential duration at 90% repolarization (APD90) was measured from monophasic epicardial recordings and indices of sympathetic activation were assessed using fast-Fourier analysis of heart rate variability. Serum epinephrine and norepinephrine were measured with radioimmunoassay. MI size was similar in the two groups. There was a marked temporal variation in VT/VF duration; during phase I, it was higher (p = 0.0087) in ETB-deficient (1,519 +/- 421 s) than in wild-type (190 +/- 34 s) rats, but tended (p = 0.086) to be lower in ETB-deficient (4.2 +/- 2.0 s) than in wild-type (27.7 +/- 8.0 s) rats during phase II. Overall, the severity of VT/VF was greater in ETB-deficient rats, evidenced by higher (p = 0.0058) mortality (72.0% vs. 32.1%). There was a temporal variation in heart rate and in the ratio of low- to high-frequency spectra, being higher (<0.001) during phase I, but lower (p < 0.05) during phase II in ETB-deficient rats. Likewise, 1 h post-MI, serum epinephrine (p = 0.025) and norepinephrine (p < 0.0001) were higher in ETB-deficient (4.20 +/- 0.54, 14.24 +/- 1.39 ng/ml) than in wild-type (2.30 +/- 0.59, 5.26 +/- 0.67 ng/ml) rats, respectively. After beta-blockade, VT/VF episodes and mortality were similar in the two groups. The ETB-receptor decreases sympathetic activation and arrhythmogenesis during the early phase of MI, but these effects diminish during evolving MI.