Recurrent immunosuppressive-responsive myocarditis in a patient with desmoplakin cardiomyopathy: a case report.

Background: Desmoplakin (DSP) cardiomyopathy is a rare genetic condition characterized by repeated inflammatory myocardial injury and is associated with ventricular arrhythmia and sudden cardiac death. Diagnosis is challenging and requires a combination of genetic testing and advanced imaging techniques. Case summary: We present the case of a 38-year-old woman with recurrent episodes of subclinical myocarditis. Investigation using cardiac magnetic resonance imaging (cMRI) and genetic testing revealed a diagnosis of DSP cardiomyopathy. Her disease was initially responsive to corticosteroid therapy but quickly relapsed when treatment was tapered. Management of her condition required significant immunosuppression and the subsequent insertion of an implantable cardiac defibrillator due to her risk of sudden cardiac death. Discussion: Cardiac MRI and genetic testing are key diagnostic techniques in the assessment of patients with recurrent myocarditis and cardiomyopathy. The management of cardiomyopathies with an inflammatory component is not completely understood; however, there is likely a key role for immune suppression therapies. Furthermore, there are several cardiomyopathy genetic variants including DSP which require careful risk stratification due to an increased risk of sudden cardiac death.

Longitudinal assessment of structural phenotype in Brugada syndrome using cardiac magnetic resonance imaging.

Background: Despite historically being considered a channelopathy, subtle structural changes have been reported in Brugada syndrome (BrS) on histopathology and cardiac magnetic resonance (CMR) imaging. It is not known if these structural changes progress over time. Objective: The study sought to assess if structural changes in BrS evolve over time with serial CMR assessment and to investigate the utility of parametric mapping techniques to identify diffuse fibrosis in BrS. Methods: Patients with a diagnosis of BrS based on international guidelines and normal CMR at least 3 years prior to the study period were invited to undergo repeat CMR. CMR images were analyzed de novo and compared at baseline and follow-up. Results: Eighteen patients with BrS (72% men; mean age at follow-up 47.4 ± 8.9 years) underwent serial CMR with an average of 5.0 ± 1.7 years between scans. No patients had late gadolinium enhancement (LGE) on baseline CMR, but 4 (22%) developed LGE on follow-up, typically localized to the right ventricular (RV) side of the basal septum. RV end-systolic volume increased over time (P = .04) and was associated with a trend toward reduction in RV ejection fraction (P = .07). Four patients showed a reduction in RV ejection fraction >10%. There was no evidence of diffuse myocardial fibrosis observed on parametric mapping. Conclusions: Structural changes may evolve over time with development of focal fibrosis, evidenced by LGE on CMR in a significant proportion of patients with BrS. These findings have implications for our understanding of the pathological substrate in BrS and the longitudinal evaluation of patients with BrS.

The role of genetic testing in diagnosis and care of inherited cardiac conditions in a specialised multidisciplinary clinic.

BACKGROUND: The diagnostic yield of genetic testing for inherited cardiac diseases is up to 40% and is primarily indicated for screening of at-risk relatives. Here, we evaluate the role of genomics in diagnosis and management among consecutive individuals attending a specialised clinic and identify those with the highest likelihood of having a monogenic disease. METHODS: A retrospective audit of 1697 consecutive, unrelated probands referred to a specialised, multidisciplinary clinic between 2002 and 2020 was performed. A concordant clinical and genetic diagnosis was considered solved. Cases were classified as likely monogenic based on a score comprising a positive family history, young age at onset, and severe phenotype, whereas low-scoring cases were considered to have a likely complex aetiology. The impact of a genetic diagnosis was evaluated. RESULTS: A total of 888 probands fulfilled the inclusion criteria, and genetic testing identified likely pathogenic or pathogenic (LP/P) variants in 330 individuals (37%) and suspicious variants of uncertain significance (VUS) in 73 (8%). Research-focused efforts identified 46 (5%) variants, missed by conventional genetic testing. Where a variant was identified, this changed or clarified the final diagnosis in a clinically useful way for 51 (13%). The yield of suspicious VUS across ancestry groups ranged from 15 to 20%, compared to only 10% among Europeans. Even when the clinical diagnosis was uncertain, those with the most monogenic disease features had the greatest diagnostic yield from genetic testing. CONCLUSIONS: Research-focused efforts can increase the diagnostic yield by up to 5%. Where a variant is identified, this will have clinical utility beyond family screening in 13%. We demonstrate the value of genomics in reaching an overall diagnosis and highlight inequities based on ancestry. Acknowledging our incomplete understanding of disease phenotypes, we propose a framework for prioritising likely monogenic cases to solve their underlying cause of disease.

Cardiac Society of Australia and New Zealand (CSANZ) Position Statement on the Follow-Up of Cardiovascular Implantable Electronic Devices 2022.

Recognising the need for a national approach for the recommended best practice for the follow-up of implanted cardiac rhythm devices to ensure patient safety, this document has been produced by the Cardiac Society of Australia and New Zealand (CSANZ). It draws on accepted practice standards and guidelines of international electrophysiology bodies. It lays out methodology, frequency, and content of follow-up, including remote monitoring; personnel, including physician, allied health, nursing and industry; paediatric and adult congenital heart patients; and special considerations including magnetic resonance imaging scanning, perioperative management, and hazard alerts.

Atrial fibrillation management during septal myectomy for hypertrophic cardiomyopathy: A systematic review.

INTRODUCTION: Atrial fibrillation is common in patients with hypertrophic cardiomyopathy, and significantly impacts mortality and morbidity. In patients with atrial fibrillation undergoing septal myectomy, concomitant surgery for atrial fibrillation may improve outcomes. METHODS: A systematic review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. All studies reporting the outcomes of combined septal myectomy and atrial fibrillation surgery were included. RESULTS: A total of 10 observational studies were identified, including 644 patients. Most patients had paroxysmal atrial fibrillation. The proportion with prior unsuccessful ablation ranged from 0 to 19%, and preoperative left atrial diameter ranged from 44 ± 17 to 52 ± 8 mm. Cox-Maze IV (n = 311) was the most common technique used, followed by pulmonary vein isolation (n = 222) and Cox-Maze III (n = 98). Patients with persistent or longstanding atrial fibrillation more frequently received Cox-Maze III/IV. Ranges of early postoperative outcomes included: mortality 0 to 7%, recurrence of atrial tachyarrhythmias 4.4 to 48%, cerebrovascular events 0 to 1.5%, and pacemaker insertion 3 to 21%. Long-term data was limited. Freedom from atrial tachyarrhythmias at 1 year ranged from 74% to 96%, and at 5 years from 52% to 100%. Preoperative predictors of late atrial tachyarrhythmia recurrence included left atrial diameter >45 mm, persistent or longstanding preoperative atrial fibrillation and longer atrial fibrillation duration. CONCLUSION: In patients with atrial fibrillation undergoing septal myectomy, the addition of ablation surgery adds low overall risk to the procedure, and likely reduces the risk of recurrent atrial fibrillation in the long term. Future randomised studies comparing septal myectomy with or without concomitant AF ablation are needed.

Pacing-associated cardiomyopathy in adult congenital heart disease.

OBJECTIVES: Long-term single-site ventricular pacing may adversely affect ventricular function, due to dyssynchronous systemic ventricular contraction. We sought to determine the incidence, predictors and outcomes of pacing-associated cardiomyopathy (PACM) in an adult congenital heart disease (ACHD) cohort. METHODS: We retrospectively identified all patients in our database with a permanent pacemaker from 2000 to 2019. Patients were followed for the primary endpoint of unexplained decline in systemic ventricular function (PACM) and the secondary endpoint of heart failure admission. RESULTS: Of 2073 patients in our database, 106 had undergone pacemaker implantation. Over a median follow-up of 9.4 years, 25 patients (24%) developed PACM, but only in those with ventricular pacing percentage (VP%) ≥70%; PACM occurred in 0% of those with VP <70% and 47% of those with VP ≥70% (p<0.001). High-burden ventricular pacing (≥70%) remained predictive of PACM in transposition of the great arteries, tetralogy of Fallot and complex biventricular repair subgroups, but not in Fontan patients. Those with PACM were more likely to be admitted with heart failure (44% vs 15%, p=0.002). Cardiac resynchronisation therapy (CRT) upgrade was performed in 11 patients, with 9 responders (82%). CONCLUSIONS: In a cohort of patients with ACHD followed long-term post-pacing, 24% developed cardiomyopathy that was significantly associated with a higher burden of ventricular pacing (VP ≥70%). Given promising response rates to CRT, patients with ACHD expected to pace in the ventricle should be closely monitored for systemic ventricular decline.

Epidemiology and clinical characteristics of atrial fibrillation in patients with inherited heart diseases.

BACKGROUND: The prevalence and clinical course of atrial fibrillation (AF) in hypertrophic cardiomyopathy (HCM) is well described, though less so for other inherited cardiomyopathies (familial dilated cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, left ventricular noncompaction); and inherited arrhythmia syndromes (long QT syndrome, Brugada syndrome or catecholaminergic polymorphic ventricular tachycardia [CPVT]). We examined the frequency, clinical characteristics and AF-related management and outcomes amongst this patient population. METHODS: We retrospectively studied consecutive probands with inherited cardiomyopathy (n = 962) and inherited arrhythmia syndromes (n = 195) evaluated between 2002 and 2018. RESULTS: AF was observed in 5% to 31% of patients, with the highest frequency in HCM. Age of AF onset was 45.8 ± 21.9 years in the inherited arrhythmia syndromes compared with 53.3 ± 15.3 years in the inherited cardiomyopathies, with four CPVT patients developing AF at a median age of 20 years. Overall, 11% of patients with AF had a transient ischemic attack or stroke of which a total of 80% were anticoagulated; with 48% of events occurring at a CHA2 DS2 -VASc < 2. Amongst sarcomere-positive HCM, AF was independently associated with age (odds ratio [OR], 1.05; 95% confidence interval [CI], 1.02-1.08; P = .0014), left atrial area (OR, 1.11; 95% CI, 1.05-1.17; P = .0005) and MYH7 variants (OR, 2.55; 95% CI, 1.16-5.61; P = .020). CONCLUSION: Up to one-third of inherited heart disease patients will develop AF. While common general population risk factors are key in patients with HCM, the genotype is independently associated with AF. Amongst inherited arrhythmia syndromes, AF is less common, though often occurs below the age of 50 years.

Twelve-lead ambulatory electrocardiographic monitoring in Brugada syndrome: Potential diagnostic and prognostic implications.

BACKGROUND: Patients with Brugada syndrome (BrS) are diagnosed and risk stratified on the basis of a spontaneous or drug-induced type 1 electrocardiographic (ECG) pattern, often at single time points not accounting for variation throughout the day. OBJECTIVES: The purpose of this study was to prospectively assess the overall burden of type 1 Brugada ECG changes using 12-lead 24-hour Holter monitoring and evaluate association with cardiac events. METHODS: From July 1, 2013 to December 31, 2015, patients with BrS were recruited from 3 Australian centers and the Australian Genetic Heart Disease Registry. All patients underwent clinical review, baseline ECG, and 12-lead 24-hour Holter assessment with precordial leads placed in the left and right second, third, and fourth intercostal spaces. The frequency, temporal, and spatial burden of type 1 BrS ECG pattern were analyzed and assessed for association with cardiac events. RESULTS: A total of 54 patients with BrS were recruited (n=44, 81% men; mean age 44 ± 13 years); the mean follow-up was 2.3 ± 2.5 years. Eleven of 32 patients (34%) initially classified as "drug-induced BrS" demonstrated a spontaneous type 1 pattern at least once over 24 hours. Patients with cardiac events had a significantly higher temporal burden of type 1 ST-segment elevation in the 24-hour monitoring period (total area under the curve 21% vs 15%; P = .008), being most pronounced between the hours of 1600 and 2400 (P = .027). CONCLUSION: Patients with BrS traditionally classified as drug-induced can exhibit spontaneous ECG changes with longer-term monitoring, particularly in the evening. Temporal burden on 12-lead Holter monitor was associated with cardiac events. Ambulatory 12-lead ECG monitoring may have potential utility in the diagnosis and risk stratification of patients with BrS.

Cardiovascular Effects of Energy Drinks in Familial Long QT Syndrome: A Randomized Cross-Over Study.

BACKGROUND: Caffeinated energy drinks may trigger serious cardiac effects. The aim of this study was to determine the cardiovascular effects of caffeinated energy drink consumption in patients with familial long QT syndrome (LQTS). METHODS AND RESULTS: From 2014-2016, 24 LQTS patients aged 16-50 years were recruited to a randomized, double-blind, cross-over study of energy drink (ED) versus control (CD) with participants acting as their own controls (one week washout). The primary study outcome was an increase in corrected QT interval (QTc) by >20ms. Secondary outcomes were changes in systolic and diastolic blood pressure. In 24 patients with LQTS (no dropout), mean age was 29±9 years, 13/24 (54%) were female, and 8/24 (33%) were probands. Intention to treat analysis revealed no significant change in QTc with ED compared with CD (12±28ms vs 16±27ms, 3% vs 4%, p=0.71). The systolic and diastolic blood pressure significantly increased with ED compared to CD (peak change 7±16mmHg vs 1±16mmHg, 6% vs 0.8%, p=0.046 and 8±10 vs 2±9mmHg, 11% vs 3% p=0.01 respectively). These changes correlated with significant increases in serum caffeine (14.6±11.3 vs 0.5±0.1µmol/L, p<0.001) and serum taurine (737±199 vs -59±22µmol/L, p<0.001). There were three patients with dangerous QTc prolongation of ≥50ms following energy drink consumption. CONCLUSION: Caffeinated energy drinks have significant haemodynamic effects in patients with LQTS, especifically an acute increase in blood pressure. Since dangerous QTc prolongation was seen in some LQTS patients, we recommend caution in young patients with LQTS consuming energy drinks.

Thoracoscopic surgical ablation versus catheter ablation for atrial fibrillation.

For patients with atrial fibrillation (AF) who are refractory to anti-arrhythmic drugs (AADs), minimally invasive video-assisted thoracoscopic surgical ablation (SA) and catheter ablation (CA) are potential alternative treatment options. The recent FAST randomized study suggested that thoracoscopic SA was superior to CA in achieving freedom of AF in patients who have failed at least one prior AAD. To assess the relative merits and risks of SA versus CA, a systematic review and meta-analysis was conducted. Electronic searches were performed using six databases from their inception to December 2014. Relevant studies comparing thoracoscopic SA and CA were identified; data were extracted and analysed according to predefined clinical endpoints. Relative risk (RR) and weighted mean difference were used as summary statistics. Freedom from AF/arrhythmias was significantly higher in SA versus CA at 12-month off-AAD (78.4 vs 53%; RR, 1.54; P < 0.0001) and on-AAD (82.6 vs 45.7%; RR, 1.85; P < 0.00001). This difference was maintained in paroxysmal and persistent AF subgroups. The SA cohort had a significantly lower requirement for repeat ablations compared with the CA cohort (4.7 vs 24.4%; RR, 0.21; P = 0.0001). However, major complications were significantly higher in the SA group (28.2 vs 7.8%; RR, 3.30; P = 0.0003), driven by pleural effusion and pneumothorax. SA may be more efficacious than CA treatment in a selected patient population with refractory AF and prior failed catheter intervention. Improved freedom from arrhythmias at up to 12-month follow-up is counterbalanced by higher procedural complication rates.

New-onset atrial fibrillation following coronary bypass surgery predicts long-term mortality: a systematic review and meta-analysis.

Atrial fibrillation (AF) is one of the most common postoperative complications following cardiac surgery. Recent evidence suggests that postoperative atrial fibrillation (POAF) may be more 'malignant' than previously thought, associated with follow-up mortality and morbidity. To evaluate the long-term survival of POAF versus No-POAF cohorts following coronary bypass surgery, the current meta-analysis with reconstructed individual patient data was performed. Electronic searches were performed using six databases from their inception to August 2014. Relevant studies with long-term survival data presented for POAF versus No-POAF were identified. Data were extracted by two independent reviewers and analysed according to predefined clinical endpoints. The pooled hazard ratio (HR) significantly favoured higher survival in No-POAF over POAF (HR 1.28; 95% CI, 1.19-1.37; I(2) = 96%; P < 0.00001). Individual patient data of 69 518 patients were available for inverted Kaplan-Meier survival curve analysis. Analysis of aggregate data using Kaplan-Meier curve methods for POAF versus No-POAF groups determined survival rates at the 1-year (95.7 vs 98%), 2-year (92.3 vs 95.4%), 3-year (88.7 vs 93.9%), 5-year (82.6 vs 89.4%) and 10-year (65.5 vs 75.3%) follow-up. Other complications including 30-day mortality, strokes, respiratory failure, pneumonia and hospitalization were significantly higher in the POAF group. New-onset AF following coronary bypass surgery is associated with significantly higher risk of mortality in short- and long-term follow-up. Current evidence suggests the need for stricter surveillance and monitoring of POAF following coronary bypass surgery.

Surgery for hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is a genetically determined cardiac disease characterised by otherwise unexplained myocardial hypertrophy of the left ventricle, and may result in left ventricular outflow tract obstruction. It is the most common cause of sudden cardiac death in young adults due to arrhythmias. Septal myectomy is a surgical treatment for HCM with moderate to severe outflow tract obstruction, and is indicated for patients with severe symptoms refractory to medical therapy. The surgical approach involves obtaining access to the interventricular septum via transaortic, transapical or transmitral approaches, and excising a portion of the hypertrophied myocardium to relieve the outflow tract obstruction. Large, contemporary series from centres experienced in septal myectomy patients have demonstrated a low early mortality of <2 %, excellent long-term survival that matches the general population, and durable relief of symptoms.

Comparing energy sources for surgical ablation of atrial fibrillation: a Bayesian network meta-analysis of randomized, controlled trials.

Simplified maze procedures involving radiofrequency, cryoenergy and microwave energy sources have been increasingly utilized for surgical treatment of atrial fibrillation as an alternative to the traditional cut-and-sew approach. In the absence of direct comparisons, a Bayesian network meta-analysis is another alternative to assess the relative effect of different treatments, using indirect evidence. A Bayesian meta-analysis of indirect evidence was performed using 16 published randomized trials identified from 6 databases. Rank probability analysis was used to rank each intervention in terms of their probability of having the best outcome. Sinus rhythm prevalence beyond the 12-month follow-up was similar between the cut-and-sew, microwave and radiofrequency approaches, which were all ranked better than cryoablation (respectively, 39, 36, and 25 vs 1%). The cut-and-sew maze was ranked worst in terms of mortality outcomes compared with microwave, radiofrequency and cryoenergy (2 vs 19, 34, and 24%, respectively). The cut-and-sew maze procedure was associated with significantly lower stroke rates compared with microwave ablation [odds ratio <0.01; 95% confidence interval 0.00, 0.82], and ranked the best in terms of pacemaker requirements compared with microwave, radiofrequency and cryoenergy (81 vs 14, and 1, <0.01% respectively). Bayesian rank probability analysis shows that the cut-and-sew approach is associated with the best outcomes in terms of sinus rhythm prevalence and stroke outcomes, and remains the gold standard approach for AF treatment. Given the limitations of indirect comparison analysis, these results should be viewed with caution and not over-interpreted.

Diffuse ventricular fibrosis is a late outcome of tachycardia-mediated cardiomyopathy after successful ablation.

BACKGROUND: Successful arrhythmia ablation normalizes ejection fraction (EF) in tachycardia-mediated cardiomyopathy, but recurrent heart failure and late sudden death have been reported. The aim of this study was to characterize the left ventricle (LV) of tachycardia-mediated cardiomyopathy patients long after definitive arrhythmia cure. METHODS AND RESULTS: Thirty-three patients with a history of successfully ablated incessant focal atrial tachycardia 64±36 months prior, and 20 healthy controls were recruited. At ablation, 18 patients had EF<50% (AT-low EF) that recovered within 3 months from 37±12 to 56±4% (P<0.001), whereas 15 patients had EF>55% (AT-normal EF). No subjects had EF of 50% to 55%. Subjects underwent echocardiography with speckle tracking and contrast-enhanced cardiac MRI with ventricular T1 mapping as an index of diffuse fibrosis. Contrast-enhanced cardiac MRI was performed using a clinical 1.5-T scanner and 0.2 mmol/kg gadolinium-diethylene triamine penta-acetic acid for contrast. Subject characteristics were similar across the 3 groups. Compared with AT-normal EF patients and controls, AT-low EF patients had lower EF (60±6 versus 64±4 and 65±4%; P<0.05), greater indexed LV end-diastolic volume (102±34 versus 84±14 and 85±16 mL/m(2); P<0.05), and greater indexed LV end-systolic volume (41±11 versus 31±7 and 30±8 mL/m(2); P<0.01) on contrast-enhanced cardiac MRI. Compared with controls, AT-low EF patients had reduced global LV corrected T1 time (442±53 versus 529±61; P<0.05) consistent with diffuse fibrosis. CONCLUSIONS: Tachycardia-mediated cardiomyopathy patients exhibit differences in LV structure and function including diffuse fibrosis long after arrhythmia cure, indicating that recovery is incomplete.

Sinus rhythm restores ventricular function in patients with cardiomyopathy and no late gadolinium enhancement on cardiac magnetic resonance imaging who undergo catheter ablation for atrial fibrillation.

BACKGROUND: Atrial fibrillation (AF) and systolic heart failure (HF) frequently coexist. Restoration of sinus rhythm by catheter ablation may result in a variable improvement in left ventricular (LV) function. Late-gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) imaging identifies irreversible structural change and may predict incomplete recovery of LV function. OBJECTIVE: To prospectively select patients with AF and symptomatic HF but without LV LGE and report the impact of AF ablation on LV function. METHODS: Patients with AF and symptomatic HF (LV ejection fraction <50%) resistant to at least 1 antiarrhythmic drug and prior electrical cardioversion underwent contrast-enhanced CMR. LGE-negative patients underwent pulmonary vein isolation and left atrial roof line with continued antiarrhythmic medications until follow-up CMR 6 months postablation. Sixteen patients (aged 52 ± 11 years; mean AF duration 37 ± 39 months; left atrial size 44 ± 13 mL/m(2)) underwent AF ablation. RESULTS: At 6 months, 15 of the 16 patients maintained sinus rhythm and underwent CMR. LV ejection fraction increased from 40% ± 10% at baseline to 60% ± 6% (P < .001) and LV end-systolic volume index decreased from 52 ± 12 to 36 ± 9 mL/m(2) (P < .001). Left atrial size decreased from 44 ± 13 to 36 ± 11 mL/m(2) (P < .01). CONCLUSIONS: In patients with AF and LV dysfunction in the absence of LGE on CMR, ventricular function normalizes following the restoration of sinus rhythm. CMR may assist in the selection of patients with combined AF and systolic HF most likely to benefit from catheter ablation.

Subtle post-procedural cognitive dysfunction after atrial fibrillation ablation.

OBJECTIVES: This study sought to determine whether post-operative neurocognitive dysfunction (POCD) occurs after ablation for atrial fibrillation (AF). BACKGROUND: Ablation for AF is a highly effective strategy; however, the risk of transient ischemic attack and stroke is approximately 0.5% to 1%. In addition, magnetic resonance imaging studies report a 7% to 14% prevalence of silent cerebral infarction. Whether cerebral ischemia results in POCD after ablation for AF is not well established. METHODS: The study included 150 patients; 60 patients undergoing ablation for paroxysmal atrial fibrillation (PAF), 30 patients undergoing ablation for persistent atrial fibrillation (PeAF), and 30 patients undergoing ablation for supraventricular tachycardia (SVT) were compared with a matched nonoperative control group of patients with AF awaiting radiofrequency ablation (n = 30). Eight neuropsychological tests were administered at baseline and at 2 days and 90 days post-operatively. The tests were administered at the same time points to the nonoperative control group. The reliable change index was used to calculate POCD. RESULTS: The prevalences of POCD at day 2 post-procedure were 28% in patients with PAF, 27% in patients with PeAF, 13% in patients with SVT, and 0% in control patients with AF (p = 0.007). At day 90, the prevalences of POCD were 13% in patients with PAF, 20% in patients with PeAF, 3% in patients with SVT, and 0% in control patients with AF (p = 0.03). When analyzing the 3 procedural groups together, 29 of 120 patients (24%) manifested POCD at day 2 and 15 of 120 patients (13%) at day 90 post-procedure (p = 0.029). On univariate analysis, increasing left atrial access time was associated with POCD at day 2 (p = 0.04) and day 90 (p = 0.03). CONCLUSIONS: Ablation for AF is associated with a 13% to 20% prevalence of POCD in patients with AF at long-term follow-up. These results were seen in a patient population with predominant CHADS2 (Congestive heart failure, Hypertension, Age ≥75 years, Diabetes mellitus, previous Stroke/transient ischemic attack) scores of 0 to 1, representing the majority of patients undergoing ablation for AF. The long-term implications of these subtle changes require further study.

Prolongation of the QTc interval predicts appropriate implantable cardioverter-defibrillator therapies in hypertrophic cardiomyopathy.

OBJECTIVES: This study sought to determine factors predicting appropriate implantable cardioverter defibrillator (ICD) therapy in a large cohort of patients with hypertrophic cardiomyopathy (HCM). BACKGROUND: HCM is the leading cause of sudden cardiac death in those age ≤35 years. ICD therapy is offered to select patients at increased risk for sudden cardiac death. Currently, there are no clinical predictors of appropriate ICD therapy in HCM. METHODS: Patients attending the HCM clinic in Sydney, Australia, and who had undergone ICD insertion were included. Baseline data on clinical and ICD characteristics were collected. The primary endpoint was the proportion of patients who experienced at least 1 appropriate therapy from the ICD. RESULTS: Of 164 HCM patients included (62% male; mean follow-up, 6 ± 4 years [range, 0 to 19 years]), 21 patients (13%) had at least 1 appropriate therapy. Corrected QT (QTc) interval was the strongest clinical predictor of appropriate ICD therapy (458 ± 30 ms vs. 430 ± 35 ms; p = 0.001). Multivariate logistic regression analysis demonstrated a 1.2-fold increased likelihood of appropriate therapy per 10-ms increase in QTc, independent of left ventricular wall thickness (LVWT) (odds ratio: 1.2; 95% confidence interval [CI]: 1.03 to 1.39; p = 0.02) and sex (odds ratio: 1.2; 95% CI: 1.07 to 1.42; p = 0.003). On analysis of cumulative event-free survival from appropriate ICD therapy, the risk for an appropriate ICD therapy in the subgroup with prolonged QT was >3-fold that in the subgroup without prolonged QT, after adjustment for LVWT (hazard ratio: 3.2; 95% CI: 1.02 to 9.88; p = 0.047) and sex (hazard ratio, 3.7; 95% CI, 1.22 to 11.41; p = 0.02). CONCLUSIONS: The findings from this study suggest that QTc interval prolongation is a novel clinical predictor of appropriate ICD therapy in HCM.

Left septal atrial tachycardias: electrocardiographic and electrophysiologic characterization of a paraseptal focus.

OBJECTIVE: The objective was to characterize the electrocardiographic and electrophysiological features of focal atrial tachycardia (FAT) originating from the left septum (LS). BACKGROUND: FAT is recognized to occur at predefined anatomic locations rather than randomly throughout the atria. We describe the ECG and EP features of ATs originating from the LS as an important site for apparent perinodal tachycardias. METHODS: Nine patients presenting with LS FAT from a consecutive series of 384 underwent EP/RFA for symptomatic FAT. RESULTS: The mean age was 56 ± 12 years; 7 female with symptoms for 36 ± 28 months. P wave morphology (PWM) was negative/positive in lead V1 and across the precordial leads and negative or negative/positive in inferior leads in all patients. Tachycardia was incessant in 6 out of 9 patients with a mean tachycardia cycle length 421 ± 56 milliseconds. His A was ahead of P wave in all patients (mean -15 ± 5 milliseconds) and earlier than CS proximal (mean 4 ± 9 milliseconds). Successful acute focal ablation achieved at a mean of 31 ± 12 milliseconds ahead of P wave with no recurrences at a mean follow-up of 30 ± 28 months. CONCLUSION: Although the left septum is an uncommon site for focal AT an awareness of this location for harboring foci is particularly important when mapping apparently right-sided septal tachycardias.