Absence of Functional Nav1.8 Channels in Non-diseased Atrial and Ventricular Cardiomyocytes

PURPOSE

Several studies have indicated a potential role for SCN10A/NaV1.8 in modulating cardiac electrophysiology and arrhythmia susceptibility. However, by which mechanism SCN10A/NaV1.8 impacts on cardiac electrical function is still a matter of debate. To address this, we here investigated the functional relevance of NaV1.8 in atrial and ventricular cardiomyocytes (CMs), focusing on the contribution of NaV1.8 to the peak and late sodium current (INa) under normal conditions in different species.

METHODS

The effects of the NaV1.8 blocker A-803467 were investigated through patch-clamp analysis in freshly isolated rabbit left ventricular CMs, human left atrial CMs and human-induced pluripotent stem cell-derived CMs (hiPSC-CMs).

RESULTS

A-803467 treatment caused a slight shortening of the action potential duration (APD) in rabbit CMs and hiPSC-CMs, while it had no effect on APD in human atrial cells. Resting membrane potential, action potential (AP) amplitude, and AP upstroke velocity were unaffected by A-803467 application. Similarly, INa density was unchanged after exposure to A-803467 and NaV1.8-based late INa was undetectable in all cell types analysed. Finally, low to absent expression levels of SCN10A were observed in human atrial tissue, rabbit ventricular tissue and hiPSC-CMs.

CONCLUSION

We here demonstrate the absence of functional NaV1.8 channels in non-diseased atrial and ventricular CMs. Hence, the association of SCN10A variants with cardiac electrophysiology observed in, e.g. genome wide association studies, is likely the result of indirect effects on SCN5A expression and/or NaV1.8 activity in cell types other than CMs.

Cardiac diagnostic work-up of ischaemic stroke

Cardioembolic sources account for 20-30% of ischaemic strokes and are important to identify considering their prognostic and therapeutic implications. During the past years, new developments have been made in the cardiac diagnostic evaluation and management of patients with ischaemic stroke, especially regarding strokes of unknown aetiology. These recent advances have had a major impact on our understanding of embolic strokes, their diagnostic work-up, and clinical management. Herein, we propose a cardiac diagnostic work-up scheme for patients with ischaemic stroke from definite cardioembolic sources and embolic strokes of undetermined source.

Prolonged Tpeak -Tend interval is a risk factor for sudden cardiac death in adults with congenital heart disease

Objective

Adult congenital heart disease (ACHD) patients are at risk of sudden cardiac death (SCD). However, methods for risk stratification are not yet well‐defined. The T_peak‐T_end (TpTe) interval, a measure of dispersion of ventricular repolarization, is a risk factor for SCD in non‐ACHD patients. We aim to evaluate whether TpTe can be used in risk stratification for SCD in ACHD patients.

Design

From an international multicenter cohort of 25 790 ACHD patients, we identified all SCD cases. Cases were matched to controls by age, gender, congenital defect, and (surgical) intervention.

Outcome Measures

TpTe was measured on a standard 12‐lead ECG. The maximum TpTe of all ECG leads (TpTe‐max), mean (TpTe‐mean), and TpTe dispersion (maximum minus minimum) were obtained. Odds ratios (OR) for SCD cases vs controls were calculated using conditional logistic regression analysis.

Results

ECGs were available for 147 cases (median age at death 33.5 years (quartiles 26.2, 48.7), 66% male) and 267 controls. The mean TpTe‐max was 97 ± 24 ms in cases vs 84 ± 17 ms in controls (P < .001); TpTe‐mean was 70 ± 16 vs 63 ± 10 ms (P < .001); and dispersion was 51 ± 22 ms vs 41 ± 16 ms (P = .02), respectively. Assessing each ECG lead separately, TpTe in lead aVR predicted SCD most accurately. TpTe in lead aVR was 71 ± 23 ms in cases vs 61 ± 13 ms in controls (P < .001). After adjusting for impaired ventricular function, heart failure symptoms, and prolonged QRS duration, the OR of SCD of TpTe in lead aVR at an optimal cutoff of 80 ms was 5.8 (95% CI 2.7‐12.4, P < .001).

Conclusions

The TpTe interval is associated with SCD in ACHD patients. Particularly, TpTe in lead aVR can be used as an independent risk factor for SCD in ACHD patients and may, therefore, add precision to current risk prediction models.

Acetylcholine Delays Atrial Activation to Facilitate Atrial Fibrillation

Background

Acetylcholine (ACh) shortens action potential duration (APD) in human atria. APD shortening facilitates atrial fibrillation (AF) by reducing the wavelength for reentry. However, the influence of ACh on electrical conduction in human atria and its contribution to AF are unclear, particularly when combined with impaired conduction from interstitial fibrosis.

Objective

To investigate the effect of ACh on human atrial conduction and its role in AF with computational, experimental, and clinical approaches.

Methods

S1S2 pacing (S1 = 600 ms and S2 = variable cycle lengths) was applied to the following human AF computer models: a left atrial appendage (LAA) myocyte to quantify the effects of ACh on APD, maximum upstroke velocity (V _max ), and resting membrane potential (RMP); a monolayer of LAA myocytes to quantify the effects of ACh on conduction; and 3) an intact left atrium (LA) to determine the effects of ACh on arrhythmogenicity. Heterogeneous ACh and interstitial fibrosis were applied to the monolayer and LA models. To corroborate the simulations, APD and RMP from isolated human atrial myocytes were recorded before and after 0.1 μM ACh. At the tissue level, LAAs from AF patients were optically mapped ex vivo using Di-4-ANEPPS. The difference in total activation time (AT) was determined between AT initially recorded with S1 pacing, and AT recorded during subsequent S1 pacing without (n = 6) or with (n = 7) 100 μM ACh.

Results

In LAA myocyte simulations, S1 pacing with 0.1 μM ACh shortened APD by 41 ms, hyperpolarized RMP by 7 mV, and increased V _max by 27 mV/ms. In human atrial myocytes, 0.1 μM ACh shortened APD by 48 ms, hyperpolarized RMP by 3 mV, and increased V _max by 6 mV/ms. In LAA monolayer simulations, S1 pacing with ACh hyperpolarized RMP to delay total AT by 32 ms without and 35 ms with fibrosis. This led to unidirectional conduction block and sustained reentry in fibrotic LA with heterogeneous ACh during S2 pacing. In AF patient LAAs, S1 pacing with ACh increased total AT from 39.3 ± 26 ms to 71.4 ± 31.2 ms (p = 0.036) compared to no change without ACh (56.7 ± 29.3 ms to 50.0 ± 21.9 ms, p = 0.140).

Conclusion

In fibrotic atria with heterogeneous parasympathetic activation, ACh facilitates AF by shortening APD and slowing conduction to promote unidirectional conduction block and reentry.

Diagnostic Accuracy of a Smartphone-Operated, Single-Lead Electrocardiography Device for Detection of Rhythm and Conduction Abnormalities in Primary Care

PURPOSE

To validate a smartphone-operated, single-lead electrocardiography (1L-ECG) device (AliveCor KardiaMobile) with an integrated algorithm for atrial fibrillation (AF) against 12-lead ECG (12L-ECG) in a primary care population.

METHODS

We recruited consecutive patients who underwent 12L-ECG for any nonacute indication. Patients held a smartphone with connected 1L-ECG while local personnel simultaneously performed 12L-ECG. All 1L-ECG recordings were assessed by blinded cardiologists as well as by the smartphone-integrated algorithm. The study cardiologists also assessed all 12L-recordings in random order as the reference standard. We determined the diagnostic accuracy of the 1L-ECG in detecting AF or atrial flutter (AFL) as well as any rhythm abnormality and any conduction abnormality with the simultaneously performed 12L-ECG as the reference standard.

RESULTS

We included 214 patients from 10 Dutch general practices. Mean ± SD age was 64.1 ± 14.7 years, and 53.7% of the patients were male. The 12L-ECG diagnosed AF/AFL, any rhythm abnormality, and any conduction abnormality in 23, 44, and 28 patients, respectively. The 1L-ECG as assessed by cardiologists had a sensitivity and specificity for AF/AFL of 100% (95% CI, 85.2%-100%) and 100% (95% CI, 98.1%-100%). The AF detection algorithm had a sensitivity and specificity of 87.0% (95% CI, 66.4%-97.2%) and 97.9% (95% CI, 94.7%-99.4%). The 1L-ECG as assessed by cardiologists had a sensitivity and specificity for any rhythm abnormality of 90.9% (95% CI, 78.3%-97.5%) and 93.5% (95% CI, 88.7%-96.7%) and for any conduction abnormality of 46.4% (95% CI, 27.5%-66.1%) and 100% (95% CI, 98.0%-100%).

CONCLUSIONS

In a primary care population, a smartphone-operated, 1L-ECG device showed excellent diagnostic accuracy for AF/AFL and good diagnostic accuracy for other rhythm abnormalities. The 1L-ECG device was less sensitive for conduction abnormalities.

Characteristics of patients initiated on edoxaban in Europe: baseline data from edoxaban treatment in routine clinical practice for patients with atrial fibrillation (AF) in Europe (ETNA-AF-Europe)

Background

Non-vitamin K antagonist (VKA) oral anticoagulants (NOACs) have substantially improved anticoagulation therapy for prevention of stroke and systemic embolism in patients with atrial fibrillation (AF). The available routine care data have demonstrated the safety of different NOACs; however, such data for edoxaban are scarce. Here, we report baseline characteristics of 13,638 edoxaban-treated patients with AF enrolled between November 2016 and February 2018.

Methods

ETNA-AF-Europe is a multinational, multi-centre, post-authorisation, observational study conducted in 825 sites in 10 European countries. Patients will be followed up for four years.

Results

Overall, 13,980 patients were enrolled of which 342 patients were excluded from the analysis. Mean patient age was 73.6 years with an average creatinine clearance of 69.4 mL/min. 56.6% were male. The calculated CHA₂DS₂-VASc and HAS-BLED mean scores were 3.1 and 2.6, respectively. Overall, 3.3, 14.6 and 82.0% of patients had low (CHA₂DS₂-VASc = 0), intermediate (CHA₂DS₂-VASc = 1) and high (CHA₂DS₂-VASc≥2) risks of stroke, respectively. High-risk patients (those with prior stroke, prior major bleeding, prior intracranial bleed or CHA₂DS₂-VASc ≥4) comprised 38.4% of the overall population. For 75.1% of patients edoxaban was their first anticoagulant prescription, whilst 16.9% switched from a VKA and 8.0% from another NOAC. A total of 23.4% of patients in ETNA-AF-Europe received the reduced dose of edoxaban 30 mg. Overall, 83.8% of patients received an edoxaban dose in line with the criteria outlined in the label.

Conclusion

Edoxaban was predominantly initiated in older, often anticoagulation-naïve, unselected European patients with AF, with a good overall adherence to the approved label.

Trial registration

NCT02944019; Date of registration: October 24, 2016.

Design and rationale of the Edoxaban Treatment in routiNe clinical prActice for patients with Atrial Fibrillation in Europe (ETNA-AF-Europe) study

AIM

Edoxaban, a nonvitamin K antagonist oral anticoagulant, is an oral factor Xa inhibitor approved for the prevention of stroke and systemic embolism in adult patients with atrial fibrillation and for the treatment and secondary prevention in adult patients with venous thromboembolism (VTE). This study details the design of the Edoxaban Treatment in routiNe clinical prActice for patients with Atrial Fibrillation in Europe (ETNA-AF-Europe) study - a postauthorization observational study, which is part of the postapproval plan for edoxaban agreed with the European Medicines Agency.

METHODS

The ETNA-AF-Europe study (Clinicaltrials.gov: NCT02944019) is a multicenter, prospective, observational study that enrolled 13 980 patients with atrial fibrillation treated with edoxaban from 852 sites across 10 European countries (Austria, Belgium, Germany, Ireland, Italy, the Netherlands, Portugal, Spain, Switzerland, and the United Kingdom). Patients treated with edoxaban were prospectively enrolled and will be followed up for 4 years with yearly follow-up visits.

ASSESSMENTS

The primary objective of the ETNA-AF-Europe study is to assess the real-world safety of edoxaban by evaluating bleeding events, including intracranial hemorrhage; drug-related adverse events, such as hepatic events; and cardiovascular and all-cause mortality. In addition, efficacy will be assessed by recording major adverse cardiovascular events including stroke, systemic embolic events, transient ischemic attacks, and also VTE episodes, acute coronary syndromes, and hospitalizations related to cardiovascular condition. Event rates will be compared with event rates reported in the PREvention oF thromboembolic events-European Registry in Atrial Fibrillation in atrial fibrillation (PREFER in AF) and PREFER in AF Prolongation registries, and in the Effective Anticoagulation with Factor Xa Next Generation in Atrial Fibrillation - Thrombolysis in Myocardial Infarction 48 study datasets.

Impact of Body Mass Index on Outcomes in the Edoxaban Versus Warfarin Therapy Groups in Patients Underwent Cardioversion of Atrial Fibrillation (from ENSURE-AF)

In the EdoxabaN versus warfarin in subjectS UndeRgoing cardiovErsion of Atrial Fibrillation study (NCT 02072434), edoxaban showed similar efficacy and safety versus enoxaparin-warfarin in patients underwent electrical cardioversion of nonvalvular atrial fibrillation. In this ancillary analysis, we compared the primary efficacy (composite of stroke, systemic embolic event, myocardial infarction, cardiovascular death, and overall study period) and safety (composite of major and clinically relevant nonmajor bleeding, on-treatment) end points in relation to body mass index (BMI; <30 vs ≥30 kg/m²). We also compared cardioversion outcomes in relation to BMI. Of 2,199 patients enrolled, 1,095 were randomized to edoxaban and 1,104 to enoxaparin-warfarin. Mean age was 64 ± 10 and 64 ± 11 years and mean BMI 30.6 and 30.7 kg/m², respectively. Cardiovascular and metabolic diseases were more prevalent in obese (n = 1067) than nonobese patients. Overall ischemic event rates were low; rates in the BMI <30 kg/m² subgroup were numerically lower than the ≥30 kg/m² subgroup, but not significantly different (odds ratio [OR], 0.74 [95% confidence interval 0.23, 2.24]). Composite major + clinically relevant nonmajor bleeding rates were low and numerically lower, but not significantly different (OR 0.88 [0.38, 2.04]), between the edoxaban and enoxaparin-warfarin arms and across weight categories. Successful cardioversion rate was higher in the BMI <30 versus ≥30 kg/m² subgroup (73.9% vs 69.9%; OR 1.22 [1.01 to 1.48]). In EdoxabaN versus warfarin in subjectS UndeRgoing cardiovErsion of Atrial Fibrillation, BMI did not significantly impact the relative efficacy and safety of edoxaban versus enoxaparin-warfarin. Nevertheless, the nonobese group had a higher rate of cardioversion success than the obese group.

Cardiac resynchronization therapy in adults with congenital heart disease

Aims

In adults with congenital heart disease (CHD) heart failure is one of the leading causes of morbidity and mortality but experience with and reported outcome of cardiac resynchronization therapy (CRT) is limited. We investigated the efficacy of CRT in adults with CHD.

Methods and results

This was a retrospective study including 48 adults with CHD who received CRT since 2003 in four tertiary referral centres. Responders were defined as patients who showed improvement in NYHA functional class and/or systemic ventricular ejection fraction by at least one category. Ventricular function was assessed by echocardiography and graded on a four point ordinal scale. Median age at CRT was 47 years (range 18-74 years) and 77% was male. Cardiac diagnosis included tetralogy of Fallot in 29%, (congenitally corrected) transposition of great arteries in 23%, septal defects in 25%, left sided lesions in 21%, and Marfan syndrome in 2% of the patients. The median follow-up duration after CRT was 2.6 years (range 0.1-8.8). Overall, 37 out of 48 patients (77%) responded to CRT either by improvement of NYHA functional class and/or systemic ventricular function. There were 11 non-responders to CRT. Of these, three patients died and four underwent heart transplantation.

Conclusion

In this cohort of older CHD patients, CRT was accomplished with a success rate comparable to those with acquired heart disease despite the complex anatomy and technical challenges frequently encountered in this population. Further studies are needed to establish appropriate guidelines for patient selection and long term outcome.

Health-related quality of life impact of a transcatheter pacing system

BACKGROUND

Transcatheter pacing systems (TPS) provide a novel, minimally invasive approach in which a miniaturized, leadless pacemaker (PM) is transfemorally implanted in the right ventricle. We evaluated the health-related quality of life (HRQoL) impact, patient satisfaction, and activity restrictions following TPS in a large prospective multicenter clinical trial.

METHODS AND RESULTS

Patients who underwent a Micra TPS implantation between December 2013 and May 2015 were included. HRQoL impact was evaluated using the Short-Form-36 (SF-36) questionnaire at baseline, 3, and 12 months. Patient satisfaction was assessed using a three-item questionnaire determining recovery, activity level, and esthetic appearance at 3 months. Implanting physicians compared the patient activity restrictions for TPS to traditional PM therapy. A total of 720 patients were implanted with a TPS (76 ± 11 years; 59% male). Of these patients, 702 (98%), 681 (95%), and 635 (88%) completed the SF-36 at baseline, 3 and 12 months, respectively. Improvements were observed at 3 and 12 months in all SF-36 domains and all attained statistical significance. Of 693 patients who completed the patient satisfaction questionnaire, 96%, 91%, 74% were (very) satisfied with their esthetic appearance, recovery, and level of activity, respectively. TPS discharge instructions were rated less restrictive in 49%, equally restrictive in 47%, and more restrictive in 4% of cases compared with traditional PM systems.

CONCLUSIONS

TPS resulted in postimplant HRQoL improvements at 3 and 12 months, and high levels of patient satisfaction at 3 months. Further, TPS was associated with less activity restrictions compared with traditional PM systems.

Comparison of non-triggered magnetic resonance imaging and echocardiography for the assessment of left atrial volume and morphology

BACKGROUND

Advanced atrial fibrillation (AF) patients have persistent AF, failed previous catheter ablation and/or an enlarged left atrium (LA), which is associated with a reduced success of AF ablation. Transthoracic echocardiography (TTE) and contrast enhanced magnetic resonance angiography (CE-MRA) are available to assess LA volume. However, it is unknown how these modalities relate in patients with advanced AF. We therefore compared the reproducibility of TTE and non-triggered CE-MRA in advanced AF patients and their ability to select patients with successful thoracoscopic AF ablation.

METHODS

Two independent observers measured LA volumes on 65 TTE and CE-MRA exams of advanced AF patients prior to AF ablation. Patients were followed after AF ablation with rhythm monitoring every 3 months for 1 year to determine AF recurrence. Inter-modality, inter- and intra-observer variability were determined using intraclass correlation coefficients (ICC). Receiver-operating characteristic (ROC) analysis was performed to determine sensitivity and specificity of TTE and CE-MRA volume and CE-MRA dimensions to identify patients with AF recurrence during follow-up.

RESULTS

LA enlargement ≥ 34 ml/m2 was present in 60% of the patients. CE-MRA and TTE demonstrated a good correlation for LA volume assessment (intraclass correlation, ICC = 0.86; p < 0.001) with larger volumes consistently measured by CE-MRA. Major discrepancies were mostly attributed to TTE acquisition. Craniocaudal enlargement discriminated patients with AF recurrence (AUC 0.67 [95% CI 0.55-0.85], p = 0.01).

CONCLUSIONS

Non-triggered CE-MRA is a viable and reproducible 3D alternative for 2D TTE to assess LA volume in advanced AF patients. Craniocaudal enlargement was the only discriminator of AF recurrence after AF ablation.

Pacemaker-Mediated Programmable Hypertension Control Therapy

Background

Many patients requiring a pacemaker have persistent hypertension with systolic blood pressures above recommended levels. We evaluated a pacemaker‐based Programmable Hypertension Control (PHC) therapy that uses a sequence of variably timed shorter and longer atrioventricular intervals.

Methods and Results

Patients indicated for dual‐chamber pacing with office systolic blood pressure (oSBP) >150 mm Hg despite stable medical therapy were implanted with a Moderato™ pulse generator that delivers PHC therapy. Patients were followed for 1 month (Run‐In period) with conventional pacing; those with persistent oSBP >140 mm Hg were included in the study and had PHC therapy activated. The co‐primary efficacy end points were changes in 24‐hour ambulatory systolic blood pressure and oSBP between baseline and 3 months. Safety was assessed by tracking adverse events. Thirty‐five patients met the initial inclusion criteria and underwent Moderato implantation. At 1 month, oSBP was <140 mm Hg in 7 patients who were excluded. PHC was activated in the remaining 27 patients with baseline office blood pressure 166±11/80±10 mm Hg despite an average of 3.2 antihypertensive medications. During the Run‐In period, oSBP and 24‐hour ambulatory systolic blood pressure decreased by 8±13 and 5±12 mm Hg (P<0.002), respectively. Compared with pre‐PHC activation measurements, oSBP decreased by another 16±15 mm Hg and 24‐hour ambulatory systolic blood pressure decreased by an additional 10±13 mm Hg (both P<0.01) at 3 months. No device‐related serious adverse effects were noted.

Conclusions

In pacemaker patients with persistent hypertension despite medical therapy, oSBP and 24‐hour ambulatory systolic blood pressure are decreased by PHC therapy. Initial indications are that this therapy is a safe and promising therapy for such patients.

Clinical Trial Registration

URL: http://www.clinicaltrials.gov. Unique identifier: NCT02282033.

Sudden cardiac death in adult congenital heart disease: can the unpredictable be foreseen?

Aims

Sudden cardiac death (SCD) is a major cause of mortality in adults with congenital heart disease (CHD). Several risk factors for SCD including conduction disturbances and ventricular dysfunction have been described previously. However, electrocardiogram (ECG) and echocardiographic parameters may change over time, and the predictive value of such temporal changes, rather than their point estimates, for SCD remains unknown.

Methods and results

This was a retrospective case-control study in adults with CHD and proven or presumed SCD and matched controls. Data were obtained from three databases including 25 000 adults with CHD. Sequential measurements were performed on electrocardiograms and echocardiograms. Ventricular function was assessed by echocardiography and graded on a four-point ordinal scale: 1, normal [ejection fraction (EF) ≥50%]; 2, mildly impaired (EF 40-49%); 3, moderately impaired (EF 30-39%); and 4, severely impaired (EF < 30%). Overall, 131 SCDs (mean age 36 ± 14 years, 67% male) and 260 controls (mean age 37 ± 13 years, 63% male) were included. At baseline, median QRS duration was 108 ms (range 58-168 ms) in SCDs and 97 ms (range 50-168 ms) in controls and increased over time at a rate of 1.6 ± 0.5 vs. 0.5 ± 0.2 ms/year in SCDs and controls, respectively (P = 0.011). QT dispersion at baseline was 61 ms (range 31-168 ms) in SCDs and 50 ms (range 21-129 ms) in controls. QT dispersion increased at a rate of 1.1 ± 0.4 ms/year in SCD victims and decreased at a rate of 0.2 ± 0.2 ms/year in controls (P = 0.004). Increase of QRS duration ≥5 ms/year was associated with an increased risk of SCD [OR 1.9, 95% confidence interval (CI) 1.1-3.3, P = 0.013]. Change from any baseline systemic ventricular function (normal, mild, or moderately impaired) to severe ventricular dysfunction over time was associated with the highest risk of SCD (OR 16.9, 95% CI 1.8-120.1, P = 0.008).

Conclusion

In adults with CHD, QRS duration and ventricular dysfunction progress over time. Progression of QRS duration and the rate of impairment of ventricular function served to identify those at increased risk of SCD.

Cardiac 123I-mIBG scintigraphy is associated with freedom of appropriate ICD therapy in stable chronic heart failure patients

AIM

Chronic heart failure (CHF) is a life-threatening clinical syndrome, partly due to sudden cardiac death (SCD). Implantable cardioverter defibrillators (ICD) for primary prevention of SCD have improved overall survival of CHF patients. However, a high percentage of patients never receives appropriate ICD therapy. This prospective multicentre study evaluated whether cardiac sympathetic activity assessed by ¹²³I-mIBG scintigraphy could be helpful in selecting patients for ICD implantation.

MATERIALS AND METHODS

135 stable CHF subjects (age 64.5±9.3years, 79% male, LVEF 25±6%) referred for prophylactic ICD implantation were enrolled in 13 institutions. All subjects underwent planar and SPECT ¹²³I-mIBG scintigraphy. Early and late heart-to-mediastinum (H/M) ratio, ¹²³I-mIBG washout (WO) and late summed scores were calculated. The primary endpoint was appropriate ICD therapy. The secondary endpoint was defined as the combined endpoint of all first cardiac events: appropriate ICD therapy, progression of heart failure (HF) and cardiac death.

RESULTS

During a median follow-up of 30months (6-68months), 24 subjects (17.8%) experienced a first cardiac event (appropriate ICD therapy [12], HF progression [6], cardiac death [6]). Late H/M ratio and defect size of ¹²³I-mIBG SPECT were not associated with appropriate ICD therapy. However, late H/M ratio was independently associated with the combined endpoint (HR 0.135 [0.035-0.517], p=0.001). Post-hoc analysis showed that the combination of late H/M ratio (HR 0.461 [0.281-0.757]) and LVEF (HR 1.052 [1.021-1.084]) was significantly associated with freedom of appropriate ICD therapy (p<0.001).

CONCLUSION

¹²³I-mIBG scintigraphy seems to be helpful in selecting CHF subjects who might not benefit from ICD implantation.

Prevention of Sudden Cardiac Death in Adults With Congenital Heart Disease: Do the Guidelines Fall Short?

BACKGROUND

Sudden cardiac death (SCD) is a major cause of mortality in adult congenital heart disease (ACHD) patients. SCD may be prevented by implantable cardioverter-defibrillator (ICD) implantation, but patient stratification remains troublesome. The 2014 Consensus Statement on Arrhythmias in ACHD patients and the 2015 European Society of Cardiology Guidelines specified recommendations for ICD implantation in ACHD patients for the first time. We assess the discriminative ability of these ICD recommendations for SCD in ACHD patients.

METHODS AND RESULTS

Of 25 790 ACHD patients in an international multicenter registry, we identified all SCD cases, matched to living controls by age, sex, congenital defect, and surgical repair. We assessed all primary prevention ICD recommendations listed in both documents. We used conditional logistic regression models to calculate odds ratios and receiver operating characteristic curves with area under the curve. Consensus Statement: One hundred twenty-four cases (median age at death, 33 years [26-44]; 67% men) and 230 controls were studied. In total, 41% of SCD cases and 17% of controls had an ICD recommendation (odds ratio, 5.9; P<0.001). European Society of Cardiology Guidelines: Of one hundred fifty-seven cases (median age at death, 33 years [26-48]; 64% men) and 292 controls, 35% and 14% had an ICD recommendation, respectively (odds ratio, 4.8; P<0.001).

CONCLUSIONS

A minority of SCD cases had an ICD recommendation according to these guidelines, whereas the majority of SCD victims remained unrecognized. With an area under the curve of 0.6 to 0.7, the discriminative ability of both guidelines was mediocre. Critical clinical reasoning when deciding on ICD implantation in ACHD patients, therefore, remains vital.

Ganglion Plexus Ablation in Advanced Atrial Fibrillation: The AFACT Study

BACKGROUND

Patients with long duration of atrial fibrillation (AF), enlarged atria, or failed catheter ablation have advanced AF and may require more extensive treatment than pulmonary vein isolation.

OBJECTIVES

The aim of this study was to investigate the efficacy and safety of additional ganglion plexus (GP) ablation in patients undergoing thoracoscopic AF surgery.

METHODS

Patients with paroxysmal AF underwent pulmonary vein isolation. Patients with persistent AF also received additional lines (Dallas lesion set). Patients were randomized 1:1 to additional epicardial ablation of the 4 major GPs and Marshall's ligament (GP group) or no extra ablation (control) and followed every 3 months for 1 year. After a 3-month blanking period, all antiarrhythmic drugs were discontinued.

RESULTS

Two hundred forty patients with a mean AF duration of 5.7 ± 5.1 years (59% persistent) were included. Mean procedure times were 185 ± 54 min and 168 ± 54 min (p = 0.015) in the GP (n = 117) and control groups (n = 123), respectively. GP ablation abated 100% of evoked vagal responses; these responses remained in 87% of control subjects. Major bleeding occurred in 9 patients (all in the GP group; p < 0.001); 8 patients were managed thoracoscopically, and 1 underwent sternotomy. Sinus node dysfunction occurred in 12 patients in the GP group and 4 control subjects (p = 0.038), and 6 pacemakers were implanted (all in the GP group; p = 0.013). After 1 year, 4 patients had died (all in the GP group, not procedure related; p = 0.055), and 9 were lost to follow-up. Freedom from AF recurrence in the GP and control groups was not statistically different whether patients had paroxysmal or persistent AF. At 1 year, 82% of patients were not taking antiarrhythmic drugs.

CONCLUSIONS

GP ablation during thoracoscopic surgery for advanced AF has no detectable effect on AF recurrence but causes more major adverse events, major bleeding, sinus node dysfunction, and pacemaker implantation. (Atrial Fibrillation Ablation and Autonomic Modulation via Thoracoscopic Surgery [AFACT]; NCT01091389).