Malignant Purkinje ectopy induced by sodium channel blockers.

BACKGROUND: Sodium channel blocker (SCB) infusion is used to unmask the electrocardiographic pattern of Brugada syndrome. The test may also induce premature ventricular complexes (PVCs) in individuals without Brugada pattern, the clinical relevance of which is little known. OBJECTIVE: The purpose of this study was to describe the prevalence of short-coupled (Sc) PVCs induced by ajmaline or flecainide in patients with suspected or documented severe ventricular arrhythmias. METHODS: We reviewed the SCB tests performed in 335 patients with suspected ventricular arrhythmias and structurally normal hearts in 9 centers. ScPVCs were defined as frequent and repetitive PVCs with an R-on-T pattern on SCB tests. Repeated SCB tests were performed in 7 patients and electrophysiological mapping of ScPVCs in 9. RESULTS: Sixteen patients (8 men; mean age 36 ± 11 years) showed ScPVCs and were included. ScPVCs appeared 229 ± 118 seconds after the initiation of infusion and displayed coupling intervals of 288 ± 28 ms. ScPVC patterns were monomorphic in 12 patients, originating from the Purkinje system in mapped patients. Repetitive PVCs were induced in 15 patients (94%) including polymorphic ventricular tachycardias in 9 (56%). SCB infusion was repeated 45 (interquartile range 0.6-46) months later and induced identical ScPVC in all. SCB test was the only mean to reveal the malignant arrhythmia in 6 patients. Catheter ablation was performed in 9 patients, resulting in arrhythmia elimination in 8 with a follow-up of 6 (interquartile range 2-9) years. CONCLUSION: SCB can induce ScPVC, mostly from Purkinje tissue, in a small subset of patients with idiopathic ventricular arrhythmias. Its high reproducibility suggests a distinct individual mechanism.

Linear lesions for treating the recurrence of persistent atrial tachyarrhythmia after cryoballoon ablation of atrial fibrillation.

BACKGROUND: There is no consensus on the most effective radiofrequency ablation strategy for the initial or repeated treatment of persistent atrial tachyarrhythmia (ATa). OBJECTIVE: To describe success and complication rates after the creation of left atrial (LA) linear lesions for recurrent persistent ATa following an index cryoballoon pulmonary vein isolation (PVI), and to identify predictors of ATa recurrence. METHODS: During March 2013 to March 2020, we prospectively included all consecutive patients undergoing repeat procedures for the treatment of persistent ATa. Radiofrequency ablation consisting of the creation of linear lesions: a roofline, a mitral isthmus and/or septal line, and a cavotricuspid isthmus line. All patients were prospectively followed up for ATa recurrence. RESULTS: Overall, 133 patients underwent 170 procedures after initial cryoballoon PVI (n=715). At least one pulmonary vein reconnection was observed in 60 patients (45.1%), all of whom underwent successful re-disconnection. After all the procedures, >90% of patients had a lesion pattern consisting of a roofline, a mitral isthmus and/or septal line, and a cavotricuspid isthmus line. ATa was terminated in 41 patients (35%). There were three cases of tamponade (3/170 procedures, 1.8%). Ninety-two patients (69.2%) were in sinus rhythm after a median (interquartile range) of 36 (21-53) months since the index cryoballoon PVI. Diagnosis-to-ablation time and LA area were predictors of recurrence in multivariable analysis. CONCLUSION: The creation of linear lesions is a safe and effective treatment strategy for the recurrence of persistent ATa after cryoballoon PVI. Longer diagnosis-to-ablation time and larger LA area were predictive of ATa recurrence.

The prevalence of left and right bundle branch block morphology ventricular tachycardia amongst patients with arrhythmogenic cardiomyopathy and sustained ventricular tachycardia: insights from the European Survey on Arrhythmogenic Cardiomyopathy.

AIMS: In arrhythmogenic cardiomyopathy (ACM), sustained ventricular tachycardia (VT) typically displays a left bundle branch block (LBBB) morphology while a right bundle branch block (RBBB) morphology is rare. The present study assesses the VT morphology in ACM patients with sustained VT and their clinical and genetic characteristics. METHODS AND RESULTS: Twenty-six centres from 11 European countries provided information on 954 ACM patients who had ≥1 episode of sustained VT spontaneously documented during patients' clinical course. Arrhythmogenic cardiomyopathy was defined according to the 2010 Task Force Criteria, and VT morphology according to the QRS pattern in V1. Overall, 882 (92.5%) patients displayed LBBB-VT alone and 72 (7.5%) RBBB-VT [alone in 42 (4.4%) or in combination with LBBB-VT in 30 (3.1%)]. Male sex prevalence was 79.3%, 88.1%, and 56.7% in the LBBB-VT, RBBB-VT, and LBBB + RBBB-VT groups, respectively (P = 0.007). First RBBB-VT occurred 5 years after the first LBBB-VT (46.5 ± 14.4 vs 41.1 ± 15.8 years, P = 0.011). An implanted cardioverter-defibrillator was more frequently implanted in the RBBB-VT (92.9%) and the LBBB + RBBB-VT groups (90%) than in the LBBB-VT group (68.1%) (P < 0.001). Mutations in PKP2 predominated in the LBBB-VT (65.2%) and the LBBB + RBBB-VT (41.7%) groups while DSP mutations predominated in the RBBB-VT group (45.5%). By multivariable analysis, female sex was associated with LBBB + RBBB-VT (P = 0.011) while DSP mutations were associated with RBBB-VT (P < 0.001). After a median follow-up of 103 (51-185) months, death occurred in 106 (11.1%) patients with no intergroup difference (P = 0.176). CONCLUSION: RBBB-VT accounts for a significant proportion of sustained VTs in ACM. Sex and type of pathogenic mutations were associated with VT type, female sex with LBBB + RBBB-VT, and DSP mutation with RBBB-VT.

Initial rhythm control with cryoballoon ablation vs drug therapy: Impact on quality of life and symptoms.

BACKGROUND: Cryoballoon ablation (CBA) as a first-line rhythm control strategy is superior to antiarrhythmic drugs (AADs) for preventing atrial fibrillation (AF) recurrence; the impact of first-line CBA on quality of life (QoL) and symptoms has not been well characterized. METHODS: Patients aged 18 to 75 with symptomatic paroxysmal AF naïve to rhythm control therapy were randomized (1:1) to CBA (Arctic Front Advance, Medtronic) or AAD (Class I or III). Symptoms and QoL were assessed at baseline, 1, 3, 6, 9, and 12 months using the EHRA classification and Atrial Fibrillation Effect on QualiTy-of-Life (AFEQT) and SF-36v2 questionnaires. Symptomatic palpitations were evaluated via patient diary. RESULTS: Overall, 107 patients were randomized to CBA and 111 to AAD; crossovers occurred in 9%. Larger improvements in the AFEQT summary, subscale and treatment satisfaction scores were observed at 12 months with CBA vs AAD (all P <0.05). At 12 months, the mean adjusted difference in the AFEQT summary score was 9.9 points higher in the CBA group (95% CI: 5.5 -14.2, P <0.001). Clinically important improvements in the SF-36 physical and mental component scores were observed at 12 months in both groups, with no significant between group differences at this timepoint. In the CBA vs AAD group, larger improvements in EHRA class were observed at 6, 9 and 12 months (P <0.05) and the incidence rate of symptomatic palpitations was lower (4.6 vs 15.2 days/year post-blanking; IRR: 0.30, P <0.001). CONCLUSIONS: In patients with symptomatic AF, first-line CBA was superior to AAD for improving AF-specific QoL and symptoms. TRIAL REGISTRATION: ClinicalTrials.gov number: NCT01803438.

Results and Predictive Factors After One Cryoablation for Persistent Atrial Fibrillation.

Cryoballoon pulmonary vein isolation (PVI) for persistent atrial fibrillation (AF) ablation is an increasingly used strategy. We aimed to determine the results and predictors of arrhythmia recurrence after a single procedure of cryoballoon PVI for patients with persistent and long-standing persistent AF. We included all consecutive patients who underwent cryoballoon PVI for the treatment of persistent symptomatic drug-refractory AF since 2012. All patients were prospectively followed to detect the recurrence of atrial tachyarrhythmia (ATa). Predictors of recurrence were assessed. Cryoballoon PVI was performed on 399 patients with persistent AF, among whom 52 (13%) had long-standing persistent AF. Patients with long-standing persistent AF had a significantly larger left atrium than those with persistent AF. A 28-mm cryoballoon was used for 322 patients (93%). In total, 359 patients (90%) completed the 12-month follow-up visit and the median follow-up was 24 months (interquartile range 43 to 13). The 2-year probability of freedom from ATa recurrence was 51% for persistent AF and 27% for long-standing persistent AF. Long-standing persistent AF and left atrial area/volume were independent predictors of ATa recurrence. Ten patients (2.5%) experienced phrenic nerve palsy, 1 tamponade (0.25%), 2 stroke (0.5%), 2 pericardial effusions (0.5%), and 5 vascular complications (1.25%). In conclusion, 2-year ATa-free survival rates were 51 and 27% for persistent and long-standing persistent AF patients, respectively. Complications were rare. Long-standing persistent AF and left-atrial area/volume were predictors of recurrence.

Cryoballoon ablation vs. antiarrhythmic drugs: first-line therapy for patients with paroxysmal atrial fibrillation.

AIMS: Treatment guidelines for patients with atrial fibrillation (AF) suggest that patients should be managed with an antiarrhythmic drug (AAD) before undergoing catheter ablation (CA). This study evaluated whether pulmonary vein isolation employing cryoballoon CA is superior to AAD therapy for the prevention of atrial arrhythmia (AA) recurrence in rhythm control naive patients with paroxysmal AF (PAF). METHODS AND RESULTS: A total of 218 treatment naive patients with symptomatic PAF were randomized (1 : 1) to cryoballoon CA (Arctic Front Advance, Medtronic) or AAD (Class I or III) and followed for 12 months. The primary endpoint was ≥1 episode of recurrent AA (AF, atrial flutter, or atrial tachycardia) >30 s after a prespecified 90-day blanking period. Secondary endpoints included the rate of serious adverse events (SAEs) and recurrence of symptomatic palpitations (evaluated via patient diaries). Freedom from AA was achieved in 82.2% of subjects in the cryoballoon arm and 67.6% of subjects in the AAD arm (HR = 0.48, P = 0.01). There were no group differences in the time-to-first (HR = 0.76, P = 0.28) or overall incidence [incidence rate ratio (IRR)=0.79, P = 0.28] of SAEs. The incidence rate of symptomatic palpitations was lower in the cryoballoon (7.61 days/year) compared with the AAD arm (18.96 days/year; IRR = 0.40, P < 0.001). CONCLUSIONS: Cryoballoon CA was superior to AAD therapy, significantly reducing AA recurrence in treatment naive patients with PAF. Additionally, cryoballoon CA was associated with lower symptom recurrence and a similar rate of SAEs compared with AAD therapy.

Cryoballoon catheter ablation versus antiarrhythmic drugs as a first-line therapy for patients with paroxysmal atrial fibrillation: Rationale and design of the international Cryo-FIRST study.

BACKGROUND: Radiofrequency current (RFC) catheter ablation for patients with paroxysmal atrial fibrillation (AF) has been shown to be safe and effective in first-line therapy. Recent data demonstrates that RFC ablation provides better clinical outcomes compared to antiarrhythmic drug (AAD) in the treatment of early AF disease. Furthermore, studies comparing RFC and cryoballoon have established comparable efficacy and safety of pulmonary vein isolation (PVI) for patients with symptomatic paroxysmal AF. OBJECTIVES: The Cryo-FIRST trial was designed to compare AAD treatment against cryoballoon PVI as a first-line therapy in treatment naïve patients with AF. Efficacy and safety will be compared between the two cohorts and amongst subgroups. METHODS: The primary hypothesis is that cryoablation is superior to AAD therapy. To test this hypothesis, patients will be randomized in a 1:1 design. Using a 90-day blanking period, primary efficacy endpoint failure is defined as (at least) one episode of atrial arrhythmia with a duration >30 sec (documented by 7-day Holter or 12-lead ECG). Secondary endpoints (Quality-of-Life, rehospitalization, arrhythmia recurrence rate, healthcare utilization, and left atrial function) and adverse events will also be evaluated. Study enrollment will include 218 patients in up to 16 centers. CONCLUSIONS: This study will be a multi-national randomized controlled trial comparing cryoablation against AAD as a first-line treatment in patients with paroxysmal AF. The results may help guide the selection of patients for early AF disease therapy via cryoballoon ablation.

Catheter ablation reduces ventricular tachycardia burden in patients with arrhythmogenic right ventricular cardiomyopathy: insights from a north-western French multicentre registry.

Aims: Studies assessing radiofrequency ablation (RFA) of ventricular tachycardia (VT) in arrhythmogenic right ventricular cardiomyopathy (ARVC) report VT recurrences, but have not evaluated the impact of RFA on relevant clinical events during follow-up. We aimed to investigate relevant RFA outcomes in a multicentric registry. Methods and results: This study included 49 patients with ARVC (46 with definite diagnosis, 3 with borderline diagnosis according to revised Task Force Criteria) who underwent 92 RFA procedures (83 endocardial, 9 combined endo-epicardial) between 1999-2015. Ventricular tachycardia recurrences and VT burden were assessed after each procedure or after the last RFA. Over a mean follow-up of 64 ± 51 months, VT-free survival was 37% at 1 year, 19% at 5 years, and 14% at 10 years. Ventricular tachycardia burden was significantly reduced after one procedure (23 vs. 11 VT episodes/year, P < 0.01) and after the last RFA (14 vs. 2 VT episodes/year, P < 0.01). Over a mean follow-up of 49 ± 52 months, clinical response after the last RFA (freedom from sudden cardiac death, VT requiring hospitalization, or heart transplantation) was 86% at 1 year, 69% at 5 years, and 60% at 10 years. Clinical response was associated with right ventricular dysfunction (RVD) and low numbers of mappable VT before the first RFA. Conclusion: RFA was predominantly targeted at the endocardial surface. Ventricular tachycardia recurrences were common, but few ARVC patients experienced major clinical events during follow-up. Further studies should investigate the benefit of extensive substrate ablation combined with endo-epicardial strategies.

Prevalence and predictive factors of left atrial tachycardia occurring after second-generation cryoballoon ablation of atrial fibrillation.

INTRODUCTION: Assess the prevalence and predictors of left atrial tachycardia (LAT) after cryoballoon ablation of pulmonary veins. METHODS AND RESULTS: Patients who underwent catheter ablation of pulmonary veins with a second-generation cryoballoon for symptomatic paroxysmal (151 of 270, 56%) or persistent (119 of 270, 44%) atrial fibrillation were entered in a single-center prospective registry. Patients who experienced postcryoballoon LAT (pcryo-LAT) were selected on the basis of 12-lead ECG characteristics. Left atrial origin was confirmed during conventional EP study and electroanatomical activation mapping, and patients were treated by RF catheter ablation. Pcryo-LAT was observed in 15 (5.6%) of 270 patients and was attributed to a reentrant mechanism in 11 patients (73%). The other four cases of pcryo-LAT were due to focal atrial tachycardia associated with reconnection of one pulmonary vein. In comparison with patients who remained in sinus rhythm, LA area (HR = 1.09; CI 1.01, 1.2; P = 0.02), LVEF (HR = 0.94; CI 0.90, 0.97; P < 0.001), and LVEF <50% (HR = 8.5; CI 3.1, 23.6; P < 0.001) were predictors of pcryo-LAT. After multivariate Cox analysis, only left ventricular ejection fraction < 50% remained predictive of pcryo-LAT, (HR = 7.8, CI 2.3 26.7, P = 0.002). With a mean survival of 23 months, 73% of patients who experienced pcryo-LAT were in sinus rhythm versus 78% of patients without pcryo-LAT (log rank P = 0.85). CONCLUSION: The prevalence of pcryo-LAT in patients with atrial fibrillation is low. Left ventricular ejection fraction < 50% is associated with an increased risk of pcryo-LAT. When treated by RF catheter ablation, the presence of pcryo-LAT is not a predictive factor of subsequent recurrence of atrial fibrillation during follow-up.

Utility of Frailty Assessment for Elderly Patients Undergoing Cardiac Resynchronization Therapy.

OBJECTIVES: The aim of this study was to evaluate the impact of frailty in the elderly on response to cardiac resynchronization therapy (CRT). BACKGROUND: CRT has been shown to improve symptoms and outcome of patients with congestive heart failure (HF) and impaired left ventricular ejection fraction (LVEF). The impact of frailty on the results of CRT is unknown. METHODS: Frailty defined as <14 of 17 points using the ONCODAGE (Outil de dépistage gériatrique en oncologie) G8 score was assessed before device implantation in candidates for CRT who were >70 years of age. The primary endpoint was the response to CRT, defined as an improvement of >5% of the LVEF and the absence of hospitalization for HF or cardiovascular death at 9 months. RESULTS: Ninety-two of 151 included patients (61%) were frail, and 89 (59%) were responders. Frailty was more frequent in nonresponders: 45 of 62 (73%) versus 47 of 89 (53%) (p = 0.014) and was identified as an independent predictor of nonresponse to CRT (R = 0.30; 95% confidence interval: 0.02 to 0.59; p = 0.039). Frailty was associated with a higher cumulative probability of hospitalization for HF (log-rank p = 0.032) and of all-cause death (log-rank p = 0.033). A G8 score <10.25 correlated with hospitalization for HF or death at 9 months (area under the curve: 0.75; 95% confidence interval: 0.63 to 0.87; cutoff <10.25; 77% sensitivity, 63% specificity). CONCLUSIONS: Frailty is as an independent predictor of nonresponse to CRT. Frail patients implanted with CRT devices have a higher risk of hospitalization for HF and mortality. Routine comprehensive geriatric assessment at the time of screening for device therapy should be recommended to optimize management. (Frailty Score Assessment for Elderly Patients Undergoing Cardiac Resynchronization Therapy [FRAILTY]; NCT02369419).

The anatomic impact of sequential, additional, ostial radiofrequency ablation following pulmonary vein cryo-isolation.

BACKGROUND: Although pulmonary vein (PV) stenosis is a serious complication of radiofrequency PV isolation, the anatomical impact of a combination of two energy sources on PV diameter has not been evaluated. The aim of this study was to evaluate the impact of supplementary point-by-point radiofrequency applications (following PV cryoablation) on the PV orifice diameter. METHODS: Forty-nine patients having undergone PV isolation for drug-refractory atrial fibrillation were included. All had undergone cardiac computed tomography before ablation and again at least 3 months afterwards. When isolation with the cryoballoon was not complete, a conventional irrigated-tip radiofrequency catheter was used for point-by-point applications. RESULTS: Of the 189 target PVs, 117 were isolated with cryotherapy alone (cryo PVs) and 72 required additional radiofrequency (hybrid PVs). The second scan (performed an average of 11.4 ± 5.4 months after) showed a decrease in diameter for all the hybrid PVs (17.2 ± 2.6 to 16.3 ± 3.4 mm; P = 0.037) but no change for the cryo PVs. This change was associated with a decrease in left superior pulmonary vein (LSPV) diameter (19.2 ± 3.0 to 17.8 ± 4.9 mm, P = 0.014). There were no changes in other veins. A subgroup analysis for the LSPV revealed a decrease for the hybrid PVs (18.8 ± 3.6 to 15.9 ± 7.1 mm, P = 0.046) but not for the cryo PVs. Significant PV stenosis was observed in three hybrid PVs (two severe stenosis of the LSPV and one moderate stenosis of the right inferior pulmonary vein) but not in cryo PVs (4.1% vs 0%, respectively; P = 0.023). CONCLUSIONS: Cryoballoon ablation of the PV with adjunct, focal, irrigated ostial RF applications may be associated with a higher risk of PV stenosis.

Dual balloon size strategy for cryoisolation of the pulmonary veins in patients with atrial fibrillation: comparison of 23 and 28mm diameter cryoballoons.

BACKGROUND: Systematic use of a 28mm balloon has been proposed for pulmonary vein cryoisolation in patients with atrial fibrillation. OBJECTIVE: To assess the results of a dual balloon size strategy using a 23 or 28mm cryoballoon catheter for pulmonary vein isolation. METHODS: A total of 118 patients (mean age 56 ± 10 years) with paroxysmal (n=85) or persistent atrial fibrillation (n=33) were enrolled. Patients with four pulmonary veins<20mm in diameter were isolated with a 23mm cryoballoon (n=29); patients with one pulmonary vein diameter ≥20mm were isolated with a 28mm cryoballoon (n=89). RESULTS: No significant difference in procedural variables was observed between the two groups. AF-free survival, after a mean follow-up of 19.9 ± 5 months, was similar in the two groups (69% vs 62%; p=0.57 and between patients with paroxysmal atrial fibrillation (68% vs 68%; p=0.91) or persistent AF (75% vs 48%; p=0.60). AF duration before the ablation procedure (p=0.005) was an independent predictor of AF recurrence. Phrenic nerve palsy rate was not statistically different in the two groups (4 [14%] vs 9 [10%]; p=0.73). The temperature in the right superior pulmonary vein (p=0.008) was an independent predictor of phrenic nerve palsy. Five patients developed left atrial flutter with the 28mm diameter balloon versus none with the 23mm balloon. CONCLUSIONS: A dual balloon size strategy was not associated with a lower AF-free survival or a higher procedure-related complication rate in patients in whom the 23mm balloon was used. Pulmonary vein isolation with a 23mm cryoballoon catheter appears to be an appropriate option in selected patients with small pulmonary vein diameters.

Normal pulmonary veins anatomy is associated with better AF-free survival after cryoablation as compared to atypical anatomy with common left pulmonary vein.

BACKGROUND: Pulmonary vein cryoablation (PVC) is a new approach in the treatment of recurrent atrial fibrillation (AF). Computed tomography (CT) can be used to evaluate the left atrium anatomy and PVs dimensions to facilitate the procedure. In radiofrequency procedures, some anatomic variants such as common left (CLPV) or right (CRPV) PV were reported as factors associated with technical procedure difficulties and potential long-term complications. We hypothesized that the absence of CLPV as determined by CT would predict better AF-free survival after PVC. METHODS AND RESULTS: We included 118 consecutive patients (mean age 56 ± 10 years; 77% males) with drug refractory paroxysmal (72%)/persistent (28%) AF, with more than 6 months follow-up, who underwent PVC. On CT scanning images performed within 1 month prior to ablation, we evaluated PV anatomic patterns: presence of CLPV or CRPV. Each patient was evaluated by 24-hour Holter monitoring within 1 and 3 months and all patients were periodically evaluated at 1, 3, and 6 months, and every 6 months thereafter. Patients were asked to record their 12-lead electrocardiogram whenever they experienced symptoms suggestive of AF. Recurrence was defined as AF that lasted at least 30 seconds. CLPV was present in 30 (25%) patients and no patients with CRPV were identified. At the end of the 13 months follow-up, patients with normal PVs had significantly better AF-free survival compared to patients with CLPV (67% vs 50%, P = 0.02). The difference was present in patients with paroxysmal AF (P = 0.008) but not in patients with persistent AF (P = 0.92). CONCLUSION: In patients undergoing cryoballoon PV isolation for AF, the presence of normal PVs pattern is associated with better AF-free survival as compared to atypical PV anatomy with CLPV, particularly in patients with paroxysmal AF.

Drug-induced pericarditis mimicking Brugada syndrome.

Brugada syndrome (BS) is associated with sudden cardiac death in patients with a structurally normal heart. The ECG pattern of BS has also been described in patients with myocardial abnormalities. Cardiac hypersensitivity and myopericarditis have been reported during long-term treatment with mesalazine. We report the case of a man, treated with mesalazine for Crohn's disease who developed drug-induced pericarditis. The ECG showed a coved ST-segment elevation in the right precordial leads V1-V3, a pattern mimicking BS. The ECG normalized in a few days after mesalazine withdrawal and the follow-up was uneventful. The ECG remained normal. Two ajmaline tests were both negative and ruled out the diagnosis of BS. This observation illustrates that a coved ST-segment elevation in the right precordial leads should not be, systematically, regarded as a marker of a specific syndrome, but may also reflect a common electrical manifestation of abnormalities in the right ventricle or pericardium.

Radioiodine ablation of the thyroid to prevent recurrence of amiodarone-induced thyrotoxicosis in patients with resistant tachyarrhythmias.

UNLABELLED: Amiodarone-induced thyrotoxicosis (AIT) is a common complication of amiodarone therapy. Although permanent withdrawal of amiodarone is recommended due notably to the risk of worsening of tachyarrhythmias, some patients may require the reintroduction of amiodarone several months after normalizing their thyroid function. We, retrospectively, assessed the effects of (131)I therapy to prevent recurrence of AIT in euthyroid patients requiring reintroduction of amiodarone. SUBJECTS AND METHODS: Amiodarone was required in 10 cases of recurrent symptomatic paroxysmal atrial fibrillation (AF) and in 5 cases of ventricular tachycardia (VT) (M = 12, F = 3, mean age: 63 +/- 14). The underlying heart disease was dilated cardiomyopathy (n = 4), ischaemic heart disease (n = 4), hypertensive heart disease (n = 2), arrhythmogenic right ventricular dysplasia (n = 27) and valvulopathy (n = 1). Two patients had idiopathic paroxysmal AF. RESULTS: A mean (131)I dose of 579 +/- 183 MBq was administered 34 +/- 37 after the episode of AIT. Amiodarone was reintroduced in 14 of 15 patients after a mean interval of 103 +/- 261 d. Fourteen patients developed definite hypothyroidism necessitating l-thyroxine but we observed no late recurrence of AIT. After a mean follow-up of 22 +/- 16 months, tachyarrhythmias were controlled in 12 of 14 patients. CONCLUSION: (131)I therapy appears to be an effective and safe approach to prevent the recurrence of AIT in a patient requiring the reintroduction of amiodarone for tachyarrhythmias.

Decreased nocturnal standard deviation of averaged NN intervals. An independent marker to identify patients at risk in the Brugada Syndrome.

AIMS: Risk-stratification of asymptomatic Brugada Syndrome (BS) patients remains a key-issue. A typical spontaneous BS-ECG pattern and ventricular tachycardia (VT)/ventricular fibrillation (VF) inducibility are two recognized risk markers. The aim of the study was to identify additional risk markers in asymptomatic BS. METHODS AND RESULTS: We have compared Holter recordings in symptomatic and in asymptomatic patients with BS. Heart rate variability (HRV), QT-interval rate-dependence and ST-segment elevation (ST-SE) were analysed. The study population included 47 BS patients (M=36, mean age=45+/-13 years) with a malignant ventricular arrhythmia in 11 cases, an unexplained syncope in 10 cases and no symptoms in the remaining 26 cases. A typical spontaneous BS-ECG was present in 21 cases and a drug-induced BS-ECG in 26 cases. A downward trend of the time domain variables of HRV was observed. During the nocturnal period, standard deviation (SD) of the 5min averaged NN intervals (SDANN) (46+/-13 vs 57+/-18ms, P=0.02) and ultra low frequency component (3287+/-2312 vs 5030+/-3270 ms(2), P=0.04) were significantly lower in symptomatic versus asymptomatic patients. In contrast, no difference was found in QT-interval rate dependence and in ST-SE. At multivariate logistic regression, VT/VF inducibility, typical spontaneous BS-ECG and a decreased nocturnal SDANN were associated with arrhythmic events (P=0.003). CONCLUSIONS: A decreased nocturnal SDANN was an independent marker of arrhythmic events in these BS patients.