Effect of early cryoballoon ablation on atrial fibrillation recurrence-A Danish nationwide register study.

INTRODUCTION: Cryoballoon ablation is a safe and efficient rhythm control strategy in atrial fibrillation (AF) patients. The impact of time from diagnosis to ablation is unclear. The aim of this study was to examine the impact of timing of first-time cryoballoon ablation on AF recurrence in a nationwide cohort of AF patients. METHODS AND RESULTS: From nationwide registers, all AF patients ≥18 years of age who underwent first-time AF cryoballoon ablation in Denmark from 2012 to 2018 were included. The AF patients were stratified by ablation timing: Early group (≤1 year after AF diagnosis), intermediate group (1-3 years after AF diagnosis), and late group (≥3 years after AF diagnosis). By adjusted Cox regression models, the effect of timing on AF recurrence was examined. This study included 1064 AF patients with a median age of 63 years. Most patients were male (66%) and had paroxysmal AF (67%). The 1-year risk of AF recurrence increased from 31% in the early group to 41% and 44% in the intermediate and late group. The hazard ratios (95% confidence intervals) were 1.28 (0.95, 1.74) in the intermediate group and 1.42 (1.09, 1.86) in the late group when compared to the early group. Continuous diagnosis-to-ablation time seemed to have the greatest impact on AF recurrence within the first 2 years. CONCLUSION: In AF patients undergoing cryoballoon ablation, late timing of ablation was associated with a significantly higher AF recurrence rate when compared to early timing of ablation. These findings support early cryoballoon ablation to improve the outcomes after ablation.

Differential gap location after radiofrequency versus cryoballoon pulmonary vein isolation: Insights from a randomized trial with protocol-mandated repeat procedure.

INTRODUCTION: Reconnections to pulmonary vein (PV) triggers of atrial fibrillation (AF) are the primary cause of AF recurrence after PV isolation (PVI) with radiofrequency (RF) or cryoballoon catheter ablation (CRYO), but method-specific contributions to PV reconduction pattern and conductive gap location are incompletely understood. METHODS: The objective of this radiofrequency versus cryoballoon catheter ablation for paroxysmal atrial fibrillation substudy was to determine procedure-specific patterns of PV reconduction in a randomized population with protocol-mandated repeat procedures, irrespective of AF recurrence. Each PV was assessed in turn and PV reconnection sites were identified by high-density electroanatomical mapping and locating the earliest activation site. Gap locations were verified by PV re-isolation. RESULTS: In 98 patients, 81% versus 76% previously isolated PVs remained isolated after CRYO versus RF (risk ratio [RR]: 1.06; 95% confidence interval [CI]: 0.96-1.18; p = .28). There were no significant differences for any PV: left superior PV: 90% versus 80%; left inferior PV: 80% versus 78%; right superior PV: 81% versus 80%, and right inferior PV: 76% versus 73%. For each reconnected PV, 34% of ipsilateral PVs were also reconnected after CRYO compared with 64% after RF (RR: 0.54; 95% CI: 0.32-0.90; p = .01). After RF, gaps were clustered by the carina and adjacent segments, whereas they were more heterogeneously distributed after CRYO. CONCLUSION: Although RF and CRYO produce similar proportions of durably isolated PVs, gap locations appear to develop in procedure-specific patterns. After RF, ipsilateral PV reconduction is more frequent and gap sites cluster by the carina, suggesting that this region should be selectively ablated for more durable PVI.

Early recurrence of atrial tachyarrhythmia indicates pulmonary vein reconduction independent of blanking period duration in the RACE-AF trial.

INTRODUCTION: Atrial tachyarrhythmia recurrence during the blanking period (early ATA) after pulmonary vein isolation (PVI) is associated with an increased risk of later recurrence, but its relationship with pulmonary vein reconduction (PVR) is poorly understood. The objective of the present study was to evaluate the relationship between early ATA and PVR. Second, to provide data on the optimal blanking period by (a) evaluating how the predictive values of ATA for PVR are affected by blanking period duration, and (b) assessing the temporal development in atrial fibrillation (AF) burden. METHODS: In this RACE-AF substudy, 91 patients with paroxysmal AF undergoing PVI randomized to radiofrequency or cryoballoon ablation were included. All patients received an implantable cardiac monitor and underwent a protocol-mandated repeat procedure after 4-6 months for assessment of PVR. ATA ≥ 30 s. ≤ 90 days after PVI constituted early ATA. RESULTS: PVR was found in 37/54 (69%) patients with early ATA and in 11/37 (30%) patients without (p < .001). The positive predictive value of ATA for PVR was independent of blanking period duration (range 0-90 days). In both patients with and without PVR, AF burden was higher in the first month after PVI, but AF burden from the second month was similar to AF burden after the conventional blanking period. CONCLUSION: Early ATA indicates PVR, and the positive predictive value is independent of the blanking period duration. Altogether, the results of this study support substantially shortening the blanking period after PVI for paroxysmal AF.

Short- and long-term risk of atrial fibrillation recurrence after first time ablation according to body mass index: a nationwide Danish cohort study.

AIMS: Overweight is associated with increased risk of atrial fibrillation (AF), but the impact of overweight and AF recurrence after ablation is less clear. Despite this, an increasing number of AF ablations are carried out in overweight patients. We investigated the impact of body mass index (BMI) on AF recurrence rates after ablation. METHODS AND RESULTS: Through Danish nationwide registers, all patients undergoing first-time AF ablation between 2010 and 2018 were identified. Exposure of interest was BMI. The primary outcome was recurrent AF, defined from either any usage of antiarrhythmic medication, AF hospitalization, cardioversion, or re-ablation. A total of 9188 patients were included. Median age and interquartile range was 64 (60-75) in the normal-weight group and 60 (53-66) in the morbidly obese. There was an increase in comorbidity burden with increasing BMI, including a higher prevalence of heart failure, chronic obstructive pulmonary disease, diabetes, and hypertension. At 1- and 5-year follow ups, recurrence rates of AF increased incrementally by BMI categories. The hazard ratios and 95% confidence intervals of recurrent AF after ablation were 1.15 (1.07-1.23), 1.18 (1.09-1.28), and 1.26 (1.13-1.41) in overweight, obese, and morbidly obese, respectively, compared with normal-weight patients. Procedure duration and X-ray dose exposure also increased with increasing BMI. CONCLUSION: Following AF ablation, recurrence rates of AF increased incrementally with increasing BMI. Therefore, aggressive weight management pre ablation in overweight patients could potentially provide substantial benefits and improve short- and long-term outcomes after ablation.

Posterior wall isolation in persistent atrial fibrillation feasibility, safety, durability, and efficacy.

INTRODUCTION: Posterior wall isolation (PWI) added to pulmonary vein isolation (PVI) is increasingly used despite limited evidence of clinical benefit. We investigated the feasibility, durability, and efficacy of index-procedure PVI + PWI radio frequency ablation (RFA) in patients with persistent atrial fibrillation (PeAF). METHODS AND RESULTS: Twenty-four patients with PeAF participated in the prospective PeAF-Box study and underwent RFA with wide area circumferential ablation, roof- and inferior lines to achieve PVI + PWI at index procedure. Follow-up included monitoring by an implantable cardiac monitor, esophagoscopy and mandated invasive lesion-reassessment at 6 months. PWI was achieved at minor procedural cost in all patients following PVI. In 33% of patients a median of three ablations in the narrow zone between the center of the posterior wall (PW) and the posterior right carina was pivotal for swift achievement of PWI. At the 6-month reassessment procedure 85% (95% confidence interval [CI]: 77%-92%) of pulmonary veins (PVs) and 46% (95% CI: 26%-67%) of PWs remained durably isolated. AF recurred in 25% and was associated with PV-reconnection (p = .02) but not PW-reconnection (p = .27). AF-burden was 0% (interquartile range [IQR]: 0%-0%) overall and after recurrence 1% (IQR: 0%-7%). CONCLUSION: Index procedure PVI + PWI for PeAF was feasible when recognizing that limited ablation in a PW center-to-right-carina zone was required in a subset of patients. Despite limited chronic PWI durability this strategy was followed by low AF-burden. A PVI + PWI strategy appears promising in ablation for PeAF.

Catheter ablation for atrial fibrillation is associated with lower incidence of heart failure and death.

AIMS: Catheter ablation for atrial fibrillation (CAF) improves symptoms, but whether CAF improves outcome is less clear. The purpose of this study was to investigate whether CAF is associated with improved outcome in atrial fibrillation (AF) patients with previous direct current (DC) cardioversion. METHODS AND RESULTS: We performed a nationwide cohort study including all patients who underwent their 1st direct current cardioversion for AF in the period 2003-15 (N = 25 439). End points were all-cause death, cardiovascular death, stroke/thromboembolism, and incident heart failure (HF). Catheter ablation for AF was treated as a time-varying covariate and the association with outcome was assessed using Cox regression. We also constructed a propensity-matched cohort and assessed the association between CAF and outcome. Median follow-up was 5.3 years (inter-quartile range 3.0-8.7 years). A total of 3509 patients (13.8%) underwent CAF during the study period. Following adjustment for age, gender, comorbidities, medications, educational level, household income, and CHA2DS2VASc score, CAF was associated with reduced risks of all-cause death, cardiovascular death, and incident HF [all-cause death: hazard ratio (HR) 0.69, P < 0.001; cardiovascular death: HR 0.68, P = 0.003; incident HF: HR 0.76, P = 0.011]. Catheter ablation for AF was not associated with a reduced risk of stroke/thromboembolism. These results were replicated in a propensity-matched cohort. CONCLUSION: In AF patients with a prior DC cardioversion, CAF was associated with a reduced risk of all-cause and cardiovascular death. This may be due to a reduced risk of HF.

Focal pulsed field ablation and ultrahigh-density mapping - versatile tools for all atrial arrhythmias? Initial procedural experiences.

BACKGROUND: Focal pulsed field ablation (FPFA) is a novel and promising method of cardiac ablation. The aim of this study was to report the feasibility, short-term safety, and procedural findings for a broad spectrum of ablated atrial arrhythmias. METHODS: Patients (n = 51) scheduled for ablation of atrial arrhythmias were prospectively included and underwent FPFA using the Galvanize CENTAURI generator with energy delivery through commercially available ablation catheters with ultrahigh-density (UHDx) 3D electroanatomic voltage/local activation time map evaluations. Workflow, procedural data, and peri-procedural technical errors and complications are described. RESULTS: Planned ablation strategy was achieved with FPFA-only in 48/51 (94%) of the cases. Ablation strategy was first-time pulmonary vein isolation (PVI) in 17/51 (36%), repeat ablation in 18/51 (38%), PVI + in 13/51 (28%), and cavotricuspid isthmus block (CTI)-only in 3/51 (6%). The mean procedure time was 104 ± 31 min (first-time PVI), 114 ± 26 min (repeat procedure), 152 ± 36 min (PVI +), and 62 ± 17 min (CTI). Mean UHDx mapping time to assess lesion formation and block after ablation was 7 ± 4 min with 5485 ± 4809 points. First pass acute (linear) isolation with bidirectional block for anatomical lesion sets was 120/124 (97%) for all PVs, 17/17 (100%) for (any) isthmus, and 14/17 (82%) for left atrium posterior wall (LAPW). We observed several time-consuming integration errors with the used ablation system (mean 3.4 ± 3.7 errors/procedure), one transient inferior ST elevation when ablating CTI resolved by intravenous nitroglycerine and one transient AV block requiring temporary pacing for > 24 h. CONCLUSIONS: FPFA was a highly versatile method to treat atrial arrhythmias with high first-pass efficiency. UHDx revealed acute homogenous low-voltage lesions in ablated areas. More data is needed to establish lesion durability and limitations of FPFA.

Characterization of durability and reconnection patterns at time of repeat ablation after single-shot pulsed field pulmonary vein isolation.

BACKGROUND: Pulsed field ablation (PFA) is a novel method of cardiac ablation where there is insufficient knowledge on the durability and reconnection patterns after pulmonary vein isolation (PVI). The aim of this study was to characterize the electrophysiological findings at time of repeat procedure in real-world atrial fibrillation (AF) patients. METHODS: Patients who underwent a repeat procedure (n=26) for symptomatic recurrent arrhythmias after index first-time treatment with single-shot PFA PVI (n=266) from July 2021 to June 2023 were investigated with 3D high-density mapping and ad-hoc re-ablation by radiofrequency or focal PFA. RESULTS: Index indication for PVI was persistent AF in 17 (65%) patients. The mean time to repeat procedure was 292 ± 119 days. Of the 26 patients (104 veins), complete durable PVI was observed in 11/26 (42%) with a durable vein isolation rate of 72/104 (69%). Two patients (8%) had all four veins reconnected. The posterior wall was durably isolated in 4/5 (80%) of the cases. The predominant arrhythmia mechanism was AF in 17/26 (65%) patients and regular atrial tachycardia (AT) in 9/26 (35%). Reconnection was observed 9/26 (35%) in right superior, 11/26 (42%) in right inferior, 7/26 (27%) in left superior, 5/26 (19%) in left inferior, p=0.31 between veins. The gaps were significantly clustered in the right-sided anterior carina compared to other regions (P=0.009). CONCLUSIONS: Durable PVI was observed in less than half of the patients at time of repeat procedure. No significant difference in PV reconnection pattern was observed, but the gap location was preferentially located at the anterior aspects of the right-sided PVs. Predominant recurrence was AF. More data is needed to establish lesion formation and durability and AT circuits after PFA.

Two decades of SVT ablation in Denmark: a trend towards higher age, more comorbidity, and less prior use of antiarrhythmic and rate-limiting pharmacotherapy-a nationwide registry-based Danish study.

BACKGROUND AND AIMS: Trends in patient selection and use of pharmacotherapy prior to catheter ablation (CA) for supraventricular tachycardia (SVT) are not well described. This study examined temporal trends in patients undergoing first-time CA for regular SVT, including atrioventricular nodal re-entry tachycardia (AVNRT), accessory pathways (APs), and ectopic atrial tachycardia (EAT) on a nationwide scale in Denmark in the period 2001-2018. METHODS AND RESULTS: Using Danish Nationwide registers, 9959 patients treated with first-time CA for SVT between 2001 and 2018 were identified, of which 6023 (61%) received CA for AVNRT, 2829 (28%) for AP, and 1107 (11%) for EAT. Median age was 55, 42, and 55 in the AVNRT, APs, and EAT group, respectively. The number of patients receiving CA increased from 1195 between 2001 and 2003 to 1914 between 2016 and 2018. The percentage of patients with a CHA2DS2-VASc score ≥ 2 increased in all patient groups. The number of patients who underwent CA with no prior use of antiarrhythmic- or rate limiting medicine increased significantly, though prior use of beta-blockers increased for AVNRT patients. Use of verapamil decreased in all three SVT groups (P < 0.05). Use of amiodarone and class 1C antiarrhythmics remained low, with the highest usage among EAT patients. CONCLUSION: Between 2001 and 2018, CA was increasingly performed in patients with SVT, primarily AVNRT- and EAT patients. The burden of comorbidities increased. Patients undergoing CA without prior antiarrhythmic- or rate-limiting drug therapy increased significantly. Use of beta-blockers increased and remained the most widely used drug.

Lower Recurrence Rates of Atrial Fibrillation and MACE Events After Early Compared to Late Ablation: A Danish Nationwide Register Study.

BACKGROUND: Guidelines recommend prioritizing treatment with antiarrhythmic drugs before referral of patients with atrial fibrillation to ablation, delaying a potential subsequent ablation. However, delaying ablation may affect ablation outcomes. We sought to investigate the impact of duration from diagnosis to ablation on the risk of atrial fibrillation recurrence and adverse events. METHODS AND RESULTS: Using Danish nationwide registries, all patients with first-time ablation for atrial fibrillation were identified and included from 2010 to 2018. Patients were divided into 4 groups by diagnosis-to-ablation time: <1.0 year (early ablation), 1.0 to 1.9 years, 2.0 to 2.9 years, and >2.9 years (late ablation). The primary end point was atrial fibrillation recurrence after the 90-day blanking period, defined by admission for atrial fibrillation, cardioversions, use of antiarrhythmic drugs, or repeat atrial fibrillation ablations. The secondary end point was a composite end point of heart failure, ischemic stroke, or death, and each event individually. The study cohort consisted of 7705 patients. The 5-year cumulative incidence of atrial fibrillation recurrence in the 4 groups was 42.9%, 54.8%, 55.9%, and 58.4%, respectively. Hazard ratios were 1.20 (95% CI, 1.07-1.35), 1.29 (95% CI, 1.13-1.47), and 1.40 (95% CI, 1.28-1.53), respectively, with the early ablation group as reference. The hazard ratio for the combined secondary end point was 1.22 (95% CI, 1.04-1.44) in the late ablation group compared with the early ablation group. CONCLUSIONS: In patients undergoing ablation for atrial fibrillation, early ablation was associated with a significantly lower risk of atrial fibrillation recurrence. Furthermore, the associated risk of heart failure, ischemic stroke, or death was significantly lower in early-compared with late-ablation patients.

Pulsed field ablation in real-world atrial fibrillation patients: clinical recurrence, operator learning curve and re-do procedural findings.

BACKGROUND: Pulsed field ablation (PFA) is a novel method of cardiac ablation demonstrated in early pre-clinical and clinical settings. The aim of this study was to report the safety and clinical efficacy of pulmonary vein isolation (PVI) with PFA for real-world atrial fibrillation (AF) patients. METHODS: All-comer AF patients (n = 121, 59% paroxysmal) were prospectively included and underwent PFA with 100% high-density voltage maps performed after PVI. Clinical outcomes were gathered by chart review. RESULTS: PVI was achieved with PFA-only in 119 (98%) of the cases. During the implementation phase the mean procedure and fluoroscopy time was reduced from 85 ± 34 to 72 ± 18 min (p = 0.044) and 22 ± 9 to 16 ± 4 (p = 0.034). We observed one phrenic nerve palsy with only partial remission at follow-up. Other adverse events were numerically comparable to standard PVI procedures. Over a mean follow-up of 308 ± 87 days, a total of 22/121 (18.2%) cases experienced clinically significant recurrence or initiation of anti-arrhythmic drugs with Kaplan-Meier event-free estimate at 365 days of 80% (88% for paroxysmal versus 69% for persistent). In five of eight re-do procedures, gaps were primarily located at the right pulmonary veins. CONCLUSIONS: PFA was a highly efficient method to achieve PVI with reductions in procedure time and fluoroscopy over the implementation period. The procedural data and clinical recurrence rates from initial trials were confirmed in real-life non-selected AF patients. More data is needed to establish lesion durability and limitations of PFA.

Posterior wall isolation in persistent atrial fibrillation. Long-term outcomes of a repeat procedure strategy.

BACKGROUND: Posterior wall isolation (PWI) added to pulmonary vein isolation (PVI) is increasingly used in ablation for persistent atrial fibrillation (PeAF) despite limited evidence of clinical benefit. We investigated the 5-year outcomes of a PVI + PWI ablation strategy with mandatory repeat procedures in PeAF. METHODS: Twenty-four patients with PeAF participated in this single-arm prospective study and underwent radiofrequency ablation (RFA) with wide area circumferential ablation (WACA), roof, and inferior lines for PVI + PWI which was reinforced if required during mandated repeat procedures after 6 months. Then, patients were followed for 60 months using continuous heart rhythm monitoring by implanted cardiac monitors (ICM) and atrial fibrillation effect on quality-of-life scoring (AFEQT; range: 20-100 points) for the initial 30 months. RESULTS: ICM-verified cumulated AF recurrence was 54% after 30 months but the ensuing AF burden was only median 0‰ [0 to 4.8‰] overall and 1‰ [0 to 8 ‰] among patients with any recurrence. AFEQT scores increased from baseline 60 points [48 to 72] to 93 points [84 to 96] at repeat procedures P < 0.0001 and further to 96 points [93 to 99] P = 0.03 after 30 months. After 60 months, at least one episode of AF had been documented in 63% and two patients (8%) were in permanent AF. CONCLUSION: Reinforced PVI + PWI was associated with low long-term AF burden and corresponding improvements in quality-of-life. Reinforced (or durable) PVI + PWI appears to be a promising strategy to treat PeAF. TRIAL REGISTRATION: ClinicalTrials.gov. Identifier: NCT05045131.

Association Between Pulmonary Vascular Volume and Cardiac Structure and Function in Patients With Atrial Fibrillation.

Pulmonary vascular abnormalities, quantified from computed tomography scans, have frequently been observed in patients with pulmonary diseases. However, little is known about pulmonary vascular changes in patients with cardiac disease. Thus, we aimed to examine the cardiopulmonary relation in patients with atrial fibrillation (AF) by comparing pulmonary vascular volume (PVV) to echocardiographic measures and AF severity. A total of 742 patients (median age 63 years, 70% men) who underwent ablation for AF were included. Preprocedural cardiac computed tomography was used to measure the total and small-vessel PVV, along with the pulmonary artery to aorta ratio and the degree of emphysema. The association between PVV and echocardiographic parameters was evaluated using a multivariable linear regression analysis. Lower total and small-vessel PVV were associated with more impaired measures of cardiac structure and function, including but not limited to left ventricular ejection fraction and peak atrial longitudinal strain. Patients with reduced total and small-vessel PVV had higher odds of having persistent AF than paroxysmal AF in the unadjusted logistic regression analyses. However, after clinical and echocardiographic adjustments, only reduced small-vessel PVV remained independently associated with persistent AF (odds ratio 1.90, 95% confidence interval 1.26 to 2.87, p = 0.002). In conclusion, pulmonary vascular remodeling is associated with persistent AF and with more impaired measures of cardiac structure and function, providing further insights into heart-lung interactions in this patient group.

Left atrial contractile strain predicts recurrence of atrial tachyarrhythmia after catheter ablation.

BACKGROUND: Despite improvement in treatment strategies of atrial fibrillation (AF), a considerable number of patients still experience recurrence of atrial tachyarrhythmia (ATA) following catheter ablation (CA). This study aimed to investigate the prognostic value of left atrial (LA) deformation analysis in a large group of patients undergoing CA for AF. METHODS: This study included 678 patients with AF. Echocardiography including two-dimensional speckle tracking echocardiography (2DSTE) was performed in all patients prior to CA. Logistic regression analysis was used to assess the association between ATA recurrence and LA strain during reservoir phase (LASr), LA strain during contraction phase (LASct), and LA strain during conduit phase (LAScd). RESULTS: During one-year follow-up, 274 (40%) experienced ATA recurrence. Median age of the included study population was 63.2 years (IQR: 55.5, 69.5) and 485 (72%) were male. Patients with recurrence had lower LASr (22.6% vs. 25.1%, p = 0.001) and LASct (10.7% vs. 12.4%, p < 0.001). No difference in LAScd was observed. After adjusting for potential clinical and echocardiographic confounders LASr (OR = 1.04, CI95% [1.01; 1.07], p = 0.015, per 1% decrease) and LASct (OR = 1.06, CI95% [1.02; 1.11], p = 0.007, per 1% decrease) remained independent predictors of recurrence. However, in patients with a normal-sized LA (LA volume index<34 mL/m2), only LASct remained an independent predictor of recurrence (OR = 1.07, CI95% [1.01; 1.12], p = 0.012, per 1% decrease). CONCLUSION: In patients undergoing CA for AF, LA deformation analysis by 2DSTE could be of use in risk stratification in clinical practice regarding ATA recurrence, even in patients with a normal-sized LA.

Radiofrequency Versus Cryoballoon Catheter Ablation for Paroxysmal Atrial Fibrillation: Durability of Pulmonary Vein Isolation and Effect on Atrial Fibrillation Burden: The RACE-AF Randomized Controlled Trial.

[Figure: see text].

Electrophysiological study and 'slow' ventricular tachycardia predict appropriate therapy: results from a single-centre implantable cardiac defibrillator follow-up.

AIMS: To account for appropriate and inappropriate therapies and cardiac death (CD) in a cohort of consecutive implantable cardiac defibrillator (ICD) eligible patients and to identify baseline predictors of these outcomes. METHODS AND RESULTS: During follow-up of 288 consecutive ICD-treated patients, clinical, biochemical, echocardiographic, arteriographic, and electrophysiological (EP) data at baseline were individually matched with survival data and electrograms retrieved during device interrogation. Predictors of therapy and CD were identified by multivariate analyses. Eighty-eight per cent of cases were secondary prevention and 12% were primary prevention. About 770 patient-years of ICD follow-up were analysed. Median follow-up was 22.7 months. Forty-eight per cent of patients had appropriate therapy for at least one ventricular tachyarrhythmia. Seventy per cent of tachycardias were successfully treated with anti-tachy pacing alone. Overall risk of therapy was higher for patients with ischaemic heart disease (IHD) than with non-IHD (51 vs. 37%; P = 0.049). Low left ventricular ejection fraction (LVEF), positive EP study, and 'slow' ventricular tachycardia predicted appropriate therapy. Cardiac death was predicted by nephropathy, low LVEF, amiodarone use, and supraventricular tachycardia (SVT). Inappropriate therapy affected 12.2% of patients and was predicted by known SVT and IHD. CONCLUSION: Electrophysiological study and slow VT predicted appropriate therapy. Amiodarone use predicted CD. Inappropriate therapy remains an important issue largely predictable by SVT.