Bidirectional Association Between Atrial Fibrillation and Myocardial Infarction, and Relation to Mortality in the Framingham Heart Study.

BACKGROUND: Individuals with both atrial fibrillation (AF) and myocardial infarction (MI) have higher mortality compared with individuals with only 1 condition. Whether mortality differs according to the temporal order of AF and MI is unclear. METHODS AND RESULTS: We included participants from the FHS (Framingham Heart Study) from 1960 and onwards. We assessed the hazard ratio (HR) of new-onset AF and MI, and mortality according to MI and AF status (prevalent and interim) using multivariable-adjusted Cox proportional hazards models. Interim diseases were modeled as time-varying variables. For the analysis of new-onset AF, 10 923 participants (55% women; mean±SD age, 54±8 years) were included. For new-onset MI, 10 804 participants (55% women; mean±SD age, 54±8 years) were included. Compared with no MI, the hazard of new-onset AF was higher in participants with prevalent (HR, 1.60 [95% CI, 1.32-1.94]) and interim MI (HR, 3.96 [95% CI, 3.18-4.91]). Both ST-segment-elevation MI and non-ST-segment-elevation MI were associated with new-onset AF. Interim AF, not prevalent AF, was associated with higher hazard rate of new-onset MI (HR, 2.21 [95% CI, 1.67-2.92]). Interim AF was associated with both ST-segment-elevation MI and non-ST-segment-elevation MI. Mortality was significantly greater among participants with AF and MI compared with participants with 1 of the 2, regardless of temporal order. CONCLUSIONS: We report a bidirectional association between AF and MI, which was observed for both non-ST-segment-elevation MI and ST-segment-elevation MI. Participants with both AF and MI had considerably higher mortality compared with participants with only 1 of the 2 conditions, regardless of order.

Five-year changes in weight and risk of atrial fibrillation in the Danish Diet, Cancer, and Health Cohort.

AIMS: Obesity is a major risk factor for atrial fibrillation (AF). Compared with stable weight, gaining weight was associated with a higher risk of incident AF in observational studies. The results, however, are conflicting regarding weight loss and risk of AF. This study aimed to assess the association between 5-year weight changes and risk of incident AF. METHODS AND RESULTS: The study was based on participants from the Danish Diet, Cancer, and Health Cohort. Body mass index (BMI) was assessed at a baseline examination and at a second examination 5 years later. Diagnoses of AF and co-morbidities were retrieved from the Danish National Patient Registry. In total, 43 758 participants without prior AF were included. The median age was 61 years and 54% were female. During a median follow-up of 15.7 years, 5312 individuals had incident AF (incidence rate 8.6/1000 person-years). Compared with stable weight, weight gain between 2.5 and 5 BMI units (kg/m2) was associated with a higher risk of AF [hazard ratio (HR) 1.24, 95% confidence interval (CI) 1.09-1.41]. Weight gain of 5 or more BMI units (kg/m2) was associated with a HR of 1.95 (95% CI 1.48-2.56) of incident AF. However, there was no statistically significant association between weight loss and risk of AF. CONCLUSION: Five-year weight gain was associated with greater risk of AF compared with stable weight in the Danish Diet, Cancer, and Health Cohort. There was no statistically significant association between weight loss and risk of AF.

We sought to understand the association between 5-year changes in weight and the future risk of atrial fibrillation, a common heart rhythm disturbance. Overweight, obesity, and underweight were associated with a higher risk of atrial fibrillation compared with normal weight.Gaining weight over a period of 5 years was associated with a higher risk of atrial fibrillation compared with maintaining a stable weight.

Interaction of genetic risk and lifestyle on the incidence of atrial fibrillation.

BACKGROUND: The relationship between combined genetic predisposition and lifestyle and the risk of incident atrial fibrillation (AF) is unclear. Therefore, we aimed to assess a possible interaction between lifestyle and genetics on AF risk. METHODS: We included AF cases and a randomly drawn subcohort of 4040 participants from the Danish Diet, Cancer and Health cohort. Lifestyle risk factors were assessed, a score was calculated, and participants were categorised as having a poor, intermediate, or ideal lifestyle. We calculated a genetic risk score comprising 142 variants, and categorised participants into low (quintile 1), intermediate (quintiles 2-4) or high (quintile 5) genetic risk of AF. RESULTS: 3094 AF cases occurred during a median follow-up of 12.9 years. Regardless of genetic risk, incidence rates per 1000 person-years were gradually higher with worse lifestyle. For participants with high genetic risk, the incidence rates of AF per 1000 person-years were 5.0 (95% CI 3.4 to 7.3) among individuals with ideal lifestyle, 6.6 (95% CI 5.4 to 8.1) among those with intermediate lifestyle and 10.4 (95% CI 9.2 to 11.8) among participants with poor lifestyle. On an additive scale, there was a positive statistically significant interaction between genetic risk and lifestyle (relative excess risk due to interaction=0.86, 95% CI 0.68 to 1.03, p<0.001). CONCLUSIONS: The rates of AF increased gradually with worse lifestyle within each category of genetic risk. We found a positive interaction on an additive scale between genetic risk and lifestyle, suggesting that risk factor modification is especially important in individuals with a high genetic risk of AF.

Clinical presentation of calmodulin mutations: the International Calmodulinopathy Registry.

AIMS: Calmodulinopathy due to mutations in any of the three CALM genes (CALM1-3) causes life-threatening arrhythmia syndromes, especially in young individuals. The International Calmodulinopathy Registry (ICalmR) aims to define and link the increasing complexity of the clinical presentation to the underlying molecular mechanisms. METHODS AND RESULTS: The ICalmR is an international, collaborative, observational study, assembling and analysing clinical and genetic data on CALM-positive patients. The ICalmR has enrolled 140 subjects (median age 10.8 years [interquartile range 5-19]), 97 index cases and 43 family members. CALM-LQTS and CALM-CPVT are the prevalent phenotypes. Primary neurological manifestations, unrelated to post-anoxic sequelae, manifested in 20 patients. Calmodulinopathy remains associated with a high arrhythmic event rate (symptomatic patients, n = 103, 74%). However, compared with the original 2019 cohort, there was a reduced frequency and severity of all cardiac events (61% vs. 85%; P = .001) and sudden death (9% vs. 27%; P = .008). Data on therapy do not allow definitive recommendations. Cardiac structural abnormalities, either cardiomyopathy or congenital heart defects, are present in 30% of patients, mainly CALM-LQTS, and lethal cases of heart failure have occurred. The number of familial cases and of families with strikingly different phenotypes is increasing. CONCLUSION: Calmodulinopathy has pleiotropic presentations, from channelopathy to syndromic forms. Clinical severity ranges from the early onset of life-threatening arrhythmias to the absence of symptoms, and the percentage of milder and familial forms is increasing. There are no hard data to guide therapy, and current management includes pharmacological and surgical antiadrenergic interventions with sodium channel blockers often accompanied by an implantable cardioverter-defibrillator.

Multifocal ectopic purkinje-related premature contractions and related cardiomyopathy.

In the past 20 years, genetic variants in SCN5A encoding the cardiac voltage-gated sodium channel Nav1.5 have been linked to a range of inherited cardiac arrhythmias: variants resulting in loss-of-function of Nav1.5 have been linked to sick sinus syndrome, atrial stand still, atrial fibrillation (AF) impaired pulse generation, progressive and non-progressive conduction defects, the Brugada Syndrome (BrS), and sudden cardiac death. SCN5A variants causing increased sodium current during the plateau phase of the cardiac action potential is associated with Long QT Syndrome type 3 (LQTS3), Torsade de Pointes ventricular tachycardia and SCD. Recently, gain-of-function variants have been linked to complex electrical phenotypes, such as the Multifocal Ectopic Purkinje-related Premature Contractions (MEPPC) syndrome. MEPPC is a rare condition characterized by a high burden of premature atrial contractions (PACs) and/or premature ventricular contractions (PVCs) often accompanied by dilated cardiomyopathy (DCM). MEPPC is inherited in an autosomal dominant fashion with an almost complete penetrance. The onset is often in childhood. The link between SCN5A variants, MEPPC and DCM is currently not well understood, but amino acid substitutions resulting in gain-of-function of Nav1.5 or introduction of gating pore currents potentially play an important role. DCM patients with a MEPPC phenotype respond relatively poorly to standard heart failure medical therapy and catheter ablation as the PVCs originate from all parts of the fascicular Purkinje fiber network. Class 1c sodium channel inhibitors, notably flecainide, have a remarkable positive effect on the ectopic burden and the associated cardiomyopathy. This highlights the importance of genetic screening of DCM patients to identify patients with SCN5A variants associated with MEPPC. Here we review the MEPPC phenotype, MEPPC-SCN5A associated variants, and pathogenesis as well as treatment options.

Genetic analysis identifies the SLC4A3 anion exchanger as a major gene for short QT syndrome.

BACKGROUND: A variant in the SLC4A3 anion exchanger has been identified as a novel cause of short QT syndrome (SQTS), but the clinical importance of SLC4A3 as a cause of SQTS or sudden cardiac death remains unknown. OBJECTIVE: The purpose of this study was to investigate the prevalence of potential disease-causing variants in SQTS patients using gene panels including SLC4A3. METHODS: In this multicenter study, genetic testing was performed in 34 index patients with SQTS. The pathogenicity of novel SLC4A3variants was validated in a zebrafish embryo heart model. RESULTS: Potentially disease-causing variants were identified in 9 (26%) patients and were mainly (15%) located in SLC4A3: 4 patients heterozygous for novel nonsynonymous SLC4A3 variants-p.Arg600Cys, p.Arg621Trp, p.Glu852Asp, and p.Arg952His-and 1 patient with the known p.Arg370His variant. In other SQTS genes, potentially disease-causing variants were less frequent (2× in KCNQ1, 1× in KCNJ2, and CACNA1C each). SLC4A3 variant carriers (n = 5) had a similar heart rate but shorter QT and J point to T wave peak intervals than did noncarriers (n = 29). Knockdown of slc4a3 in zebrafish resulted in shortened heart rate-corrected QT intervals (calculated using the Bazett formula) that could be rescued by overexpression of the native human SLC4A3-encoded protein (AE3), but neither by the mutated AE3 variants p.Arg600Cys, p.Arg621Trp, p.Glu852Asp nor by p.Arg952His, suggesting pathogenicity of these variants. Dysfunction in slc4a3/AE3 was associated with alkaline cytosol and shortened action potential of cardiomyocytes. CONCLUSION: In about a quarter of patients with SQTS, a potentially disease-causing variant can be identified. Nonsynonymous variants in SLC4A3 represent the most common cause of SQTS, underscoring the importance of including SLC4A3 in the genetic screening of patients with SQTS or sudden cardiac death.

Polygenic risk scores in coronary artery disease.

PURPOSE OF REVIEW: Recent advances in genetics have facilitated the calculation of polygenic risk scores (PRSs) based on common genetic risk variants of coronary artery disease (CAD). Here, we provide an explanation of the genetic basis for PRSs and review recent literature investigating PRSs and the clinical utility for different aspects of CAD. RECENT FINDINGS: CAD-based PRSs are strongly associated with atherosclerosis burden in the coronary arteries and other vascular beds. In multiple studies, PRSs have proven to be a measure of CAD risk, more powerful than most established risk factors alone, that can be used from early life to stratify individuals into varying trajectories of lifetime risk. When implemented in risk stratification models for primary prevention of cardiovascular disease, PRSs provide modest improvements in discrimination (C-index generally increasing 0-4% points) and reclassification, but yield significant clinical benefit as a risk enhancer. Additionally, data suggest possible value of PRSs for aiding decisions in other aspects of diagnostics and treatment in CAD. SUMMARY: Once genotyped, the genetic information may be used to calculate an infinite number of PRSs and contribute to personalize medicine providing clinical value for risk stratification, diagnostics and treatment in CAD as well as in other diseases.

Five-year changes in alcohol intake and risk of atrial fibrillation: a Danish cohort study.

AIMS: Alcohol intake is a well-established risk factor for atrial fibrillation (AF). However, evidence on the effects of changes in alcohol intake to primary AF prevention is sparse. The aim of this study was to examine the association between 5-year changes in alcohol intake and the risk of incident AF. METHODS AND RESULTS: This study was based on the Danish cohort study Diet, Cancer and Health. Lifestyle factors were assessed using questionnaires at a recruitment research examination and a second examination 5 years later. Diagnoses of AF and comorbidities were retrieved from the Danish National Patient Registry. 43 758 participants without prior AF were included. The median age was 61 (25th-75th percentile 58-66) years and 54% were female. Over a median follow-up time of 15.7 years, 5312 participants had incident AF (incidence rate 8.6/1000 person-years). Compared with stable intake, increases in alcohol intake to ≥21 drinks/week from ≤6.9 drinks/week (HR: 1.38, 95% CI: 1.09-1.72) or 14-20.9 drinks/week (HR: 1.27, 95% CI: 1.01-1.59) at baseline were associated with a higher risk of AF. In contrast, we did not observe a statistically significant association between reductions in alcohol intake and the risk of AF. CONCLUSION: A 5-year increase in alcohol intake was associated with a greater risk of AF compared with a stable low/moderate intake.

Workforce attachment after a congenital long QT syndrome diagnosis: a Danish nationwide study.

OBJECTIVE: To examine workforce attachment among patients with congenital long QT syndrome (cLQTS) following diagnosis and identify factors associated with workforce attachment. METHODS AND RESULTS: In this nationwide cohort study, all patients diagnosed with cLQTS in Denmark between 1996 and 2016 aged 18-60 years at diagnosis were identified using nationwide registries. Patients attached to the workforce at diagnosis were included. Attachment to the workforce 1 year after cLQTS diagnosis was examined and compared with a background population matched 1:4 on age, sex and employment status. Multiple logistic regression was performed to identify factors associated with 1-year workforce detachment among patients with cLQTS. 298 patients fulfilled the inclusion criteria. Six months after cLQTS diagnosis, 90.9% of patients with cLQTS were attached to the workforce compared with 95.0% in the background population (p=0.006 for difference). One year after diagnosis, 93.3% of patients with cLQTS were attached to the workforce compared with 93.8% in the background population (p=0.26). Among patients with cLQTS, a severe cLQTS disease manifestation was associated with workforce detachment 1 year after diagnosis (compared with asymptomatic patients; aborted cardiac arrest OR 20.4 (95% CI, 1.7 to 249.9); ventricular tachycardia/syncope OR 10.9 (95% CI, 1.1 to 110.5)). No other associated factors were identified. CONCLUSIONS: More than 90% of patients with cLQTS remained attached to the workforce 1 year after diagnosis, which was similar to a matched background population. Patients with a severe cLQTS disease manifestation were less likely to be attached to the workforce 1 year after diagnosis.

Long-term cancer risk in heterozygous familial hypercholesterolemia relatives: a 25-year cohort study.

BACKGROUND: Heterozygous familial hypercholesterolemia (HeFH) due to low-density lipoprotein receptor (LDLR) mutations predisposes patients to highly elevated levels of cholesterol, and patients are at increased risk of adverse cardiovascular events and other morbidities. Whether the LDLR mutation and high cholesterol levels affect the risk of cancer remains unknown. The purpose of the present study was to assess the long-term cancer risk in HeFH relatives. METHODS: Study participants were identified by cascade screening during 1992-1994. A comparison cohort was matched 10:1 to the relatives from the Danish general population based on birth year, gender and address. All participants were followed until a cancer diagnosis, migration, death, or end of follow-up as of December 31, 2019. The primary endpoint was any incident cancer diagnosis. RESULTS: In total, we included 221 relatives with a median age of 37 years (interquartile range: 27-53 years). A total of 117 (53%) of the relatives carried a LDLR gene mutation. The crude hazard ratio of our primary endpoint did not reveal any differences in cancer incidence in mutation-carrying relatives compared with the general population cohort (1.18; 95% CI, 0.81-1.71). Nonmutation-carrying relatives however had a lower cancer incidence than the general population (0.45: 95% CI, 0.26-0.80). Thus, the risk among mutation-carrying HeFH relatives compared with nonmutation-carrying HeFH relatives was increased (HR: 2.39; 95% CI, 1.24-4.61). CONCLUSION: In Denmark, LDLR mutation-carrying HeFH relatives did not have a different cancer risk than the general population. In contrast, nonmutation-carrying relatives had a lower risk of cancer.

Outcome after out-of-hospital cardiac arrest in patients with ischaemic and non-ischaemic heart disease: A Danish tertiary-center cohort study.

Background: Mortality following out-of-hospital cardiac arrest (OHCA) is high, and studies on return to work show varying results. It remains uncertain whether mortality and return to work differs between patients with ischaemic heart disease (IHD) and non-ischaemic heart disease (non-IHD). Aim: To investigate all-cause mortality, cardiac death, and return to work among patients admitted after OHCA with IHD and non-IHD. Methods: We included 234 consecutive patients admitted to Aarhus University Hospital with OHCA, who were not declared dead in the prehospital setting or upon arrival. Patients were divided into an IHD and a non-IHD group based on history of myocardial infarction, percutaneous coronary intervention, coronary artery bypass graft surgery, or signs of obstructive IHD on the admission coronary angiography. Outcome in terms of all-cause mortality, cardiac death, and return to work was evaluated. Results: All-cause mortality after one month, one year, and five years was 41.9%, 49.1%, and 54.3%. There was no difference in all-cause mortality or cardiac death between IHD and non-IHD patients (all-cause mortality: adjusted HR 0.78, 95% CI, 0.53-1.14; P = 0.19) and cardiac death: adjusted HR 0.93, 95% CI, 0.60-1.43; P = 0.73). Among patients working prior to OHCA the cumulative incidence of patients returning to work was 62.3% after five years with no statistically significant difference between groups. Conclusion: A favourable outcome was observed in patients admitted after OHCA with a non-significant trend toward a higher mortality in non-IHD patients, possibly indicating that IHD is a favourable cause of cardiac arrest.

Cardiac Performance and Cardiopulmonary Fitness After Infection With SARS-CoV-2.

Aims: Persistent cardiac symptoms are an increasingly reported phenomenon following COVID-19. However, the underlying cause of cardiac symptoms is unknown. This study aimed to identify the underlying causes, if any, of these symptoms 1 year following acute COVID-19 infection. Methods and Results: 22 individuals with persistent cardiac symptoms were prospectively investigated using echocardiography, cardiovascular magnetic resonance (CMR), 6-min walking test, cardio-pulmonary exercise testing and electrocardiography. A median of 382 days (IQR 368, 442) passed between diagnosis of COVID-19 and investigation. As a cohort their echocardiography, CMR, 6-min walking test and exercise testing results were within the normal ranges. There were no differences in left ventricular ejection fraction (61.45 ± 6.59 %), global longitudinal strain (19.80 ± 3.12 %) or tricuspid annular plane systolic excursion (24.96 ± 5.55 mm) as measured by echocardiography compared to a healthy control group. VO2 max (2045.00 ± 658.40 ml/min), % expected VO2 max (114.80 ± 23.08 %) and 6-minute distance walked (608.90 ± 54.51 m) exceeded that expected for the patient cohort, whilst Troponin I (5.59 ± 6.59 ng/l) and Nt-proBNP (88.18 ± 54.27 ng/l) were normal. Conclusion: Among a cohort of 22 patients with self-reported persistent cardiac symptoms, we identified no underlying cardiac disease or reduced cardiopulmonary fitness 1 year following COVID-19.

Arrhythmic risk prediction in arrhythmogenic right ventricular cardiomyopathy: external validation of the arrhythmogenic right ventricular cardiomyopathy risk calculator.

AIMS: Arrhythmogenic right ventricular cardiomyopathy (ARVC) causes ventricular arrhythmias (VAs) and sudden cardiac death (SCD). In 2019, a risk prediction model that estimates the 5-year risk of incident VAs in ARVC was developed (ARVCrisk.com). This study aimed to externally validate this prediction model in a large international multicentre cohort and to compare its performance with the risk factor approach recommended for implantable cardioverter-defibrillator (ICD) use by published guidelines and expert consensus. METHODS AND RESULTS: In a retrospective cohort of 429 individuals from 29 centres in North America and Europe, 103 (24%) experienced sustained VA during a median follow-up of 5.02 (2.05-7.90) years following diagnosis of ARVC. External validation yielded good discrimination [C-index of 0.70 (95% confidence interval-CI 0.65-0.75)] and calibration slope of 1.01 (95% CI 0.99-1.03). Compared with the three published consensus-based decision algorithms for ICD use in ARVC (Heart Rhythm Society consensus on arrhythmogenic cardiomyopathy, International Task Force consensus statement on the treatment of ARVC, and American Heart Association guidelines for VA and SCD), the risk calculator performed better with a superior net clinical benefit below risk threshold of 35%. CONCLUSION: Using a large independent cohort of patients, this study shows that the ARVC risk model provides good prognostic information and outperforms other published decision algorithms for ICD use. These findings support the use of the model to facilitate shared decision making regarding ICD implantation in the primary prevention of SCD in ARVC.

Diagnostic Yield of Genetic Testing in Young Patients With Atrioventricular Block of Unknown Cause.

Background The cause of atrioventricular block (AVB) remains unknown in approximately half of young patients with the diagnosis. Although variants in several genes associated with cardiac conduction diseases have been identified, the contribution of genetic variants in younger patients with AVB is unknown. Methods and Results Using the Danish Pacemaker and Implantable Cardioverter Defibrillator (ICD) Registry, we identified all patients younger than 50 years receiving a pacemaker because of AVB in Denmark in the period from January 1, 1996 to December 31, 2015. From medical records, we identified patients with unknown cause of AVB at time of pacemaker implantation. These patients were invited to a genetic screening using a panel of 102 genes associated with inherited cardiac diseases. We identified 471 living patients with AVB of unknown cause, of whom 226 (48%) accepted participation. Median age at the time of pacemaker implantation was 39 years (interquartile range, 32-45 years), and 123 (54%) were men. We found pathogenic or likely pathogenic variants in genes associated with or possibly associated with AVB in 12 patients (5%). Most variants were found in the LMNA gene (n=5). LMNA variant carriers all had a family history of either AVB and/or sudden cardiac death. Conclusions In young patients with AVB of unknown cause, we found a possible genetic cause in 1 out of 20 participating patients. Variants in the LMNA gene were most common and associated with a family history of AVB and/or sudden cardiac death, suggesting that genetic testing should be a part of the diagnostic workup in these patients to stratify risk and screen family members.

Cardiac computed tomography-verified right ventricular lead position and outcomes in cardiac resynchronization therapy.

PURPOSE: To evaluate the association between different right ventricular (RV) lead positions as assessed by cardiac computed tomography (CT) and echocardiographic and clinical outcomes in patients receiving cardiac resynchronization therapy (CRT). METHODS: We reviewed patient records of all 278 patients included in two randomized controlled trials (ImagingCRT and ElectroCRT) for occurrence of heart failure (HF) hospitalization or all-cause death (primary endpoint) during long-term follow-up. Outcomes were compared between RV lead positions using adjusted Cox regression analysis. Six months after CRT implantation, we estimated left ventricular (LV) reverse remodeling by measuring LV end-systolic and end-diastolic volumes by echocardiography. Changes from baseline to 6 months follow-up were compared between RV lead positions. Device-related complications were recorded at 6-month follow-up. RESULTS: During median (interquartile range) follow-up of 4.7 (2.9-7.1) years, the risk of meeting the primary endpoint was similar for patients with non-apical vs. apical RV lead position (adjusted hazard ratio (HR) 0.78, 95% confidence interval (CI) 0.54-1.12, p = 0.17) and free wall vs. septal RV lead position (adjusted HR 1.03, 95% CI 0.72-1.47, p = 0.86). Changes in LV ejection fraction and dimensions were similar with the different RV lead positions. We observed no differences in device-related complications relative to the RV lead position. CONCLUSIONS: In patients receiving CRT, the risk of HF hospitalization or all-cause death during long-term follow-up, and LV remodeling and incidence of device-related complications after 6 months are not associated with different anatomical RV lead position as assessed by cardiac CT.

Electrocardiographic Findings, Arrhythmias, and Left Ventricular Involvement in Familial ST-Depression Syndrome.

BACKGROUND: Familial ST-depression syndrome is an inherited disease characterized by persistent, nonischemic ST-deviations, and risk of arrhythmias and heart failure. We aimed at further characterizing the ECG, arrhythmias, and structural characteristics associated with this novel syndrome. METHODS: Retrospective analysis of data from consecutive families with familial ST-depression Syndrome in Denmark. ECG features, prevalence and type of arrhythmias, occurrence of systolic dysfunction, and medium-term outcome were analyzed. RESULTS: Forty affected individuals (43% men; mean age at diagnosis 49.1 years) from 14 apparently unrelated families with ≥2 affected members were included. Autosomal dominant inheritance was observed in all families. The ECG phenotype seemed to develop in prepuberty and the ST-deviations were persistent and most pronounced in leads V4/V5/II, respectively. Serial ECG analyses showed stable to slow progression of the ECG phenotype. Exercise accentuated the ST-deviations with a maximum difference between rest/stress (mean) of -117 µV in lead V5. During a mean follow-up of 9.3±7.1 years 5 (13%) patients developed sustained ventricular arrhythmias or (aborted) sudden cardiac death, 10 (25%) developed atrial fibrillation, 2 (5%) other supraventricular arrhythmias, and 10 (25%) were diagnosed with left ventricular ejection fraction ≤50%. The ventricular arrhythmias were polymorphic with relatively short-coupled premature ventricular contractions at onset (300-360 ms); no QT prolongation was observed. Seven patients had at least one catheter ablation; 5 for supraventricular arrhythmias and 2 for ventricular arrhythmias. Males experienced more arrhythmic end points than females (P<0.01). CONCLUSIONS: The familial ST-depression ECG phenotype is stable to slowly progressive after medium-term follow-up. Clinically, both supra- and ventricular arrhythmias are common; as are some degree of left ventricular systolic dysfunction. Familial ST-depression represent a novel inherited cause of polymorphic ventricular tachycardia.

Familial risk of atrioventricular block in first-degree relatives.

OBJECTIVE: Rare cases of genetically inherited atrioventricular block (AVB) have been reported; however, the heredity of AVB remains unknown. We aimed to assess the heredity of AVB. DESIGN, SETTING AND PARTICIPANTS: Using data from the Danish Civil Registration Registry, we established a nationwide cohort of individuals with parental links. Data were merged with information from the Danish Pacemaker and Implantable Cardioverter Defibrillator Registry, containing information on all pacemaker implantations performed in Denmark during the study period, to identify patients who received a first-time pacemaker because of AVB. RESULTS: A total of 4 648 204 individuals had parental links and a total of 26 880 consecutive patients received a first-time pacemaker due to AVB. Overall, the adjusted rate ratio (RR) of pacemaker implantation due to AVB was 2.1 (95% CI 1.8 to 2.5) if a father, mother or sibling had AVB compared with the risk in the general population. The adjusted RR was 2.2 (1.7-2.9) for offspring of mothers with AVB, 1.9 (1.5-2.4) for offspring of fathers with AVB and 3.5 (2.3-5.4) for siblings to a patient with AVB. The risk increased inversely proportionally with the age of the index case at the time of pacemaker implantation. The corresponding adjusted RRs were 15.8 (4.8-52.3) and 10.0 (3.3-30.4) if a mother or father, respectively, had a pacemaker implantation before 50 years. CONCLUSION AND RELEVANCE: First-degree relatives to a patient with AVB carry an increased risk of AVB with the risk being strongly inversely associated with the age of the index case at pacemaker implantation. These findings indicate a genetic component in the development of AVB in families with an early-onset disease.

Recurrent atrial arrhythmia in a randomised controlled trial comparing contact force-guided and contact force-blinded ablation for typical atrial flutter.

BACKGROUND: Contact force (CF)-guided catheter ablation (CA) is a novel technology developed to improve efficacy and reduce complications. In a randomised controlled trial (RCT), we previously documented that after 3 months, rate of persistent conduction block was similar with and without using CF while performing CA for typical atrial flutter (AFL). Clinical effect of CF on recurrent arrhythmia is unknown. Our objective is to study recurrent atrial arrhythmia during 12-month follow-up in a RCT investigating whether CF-guided CA for typical AFL is superior to CF-blinded CA. METHODS: Patients were randomised 1:1 to CA guided by CF (intervention group) or blinded to CF (control group). After 12 months, patients attended clinical check-up preceded by a 5-day ambulatory Holter monitor recording. Primary outcome was any recurrent atrial arrhythmia ≥ 30 s within 12 months and documented in 12-lead ECG or Holter monitor recording. RESULTS: We included 156 patients, four patients withdrew consent and two died during follow-up. Thus, 150 patients were included in final analysis. Recurrent arrhythmia was detected in 36 of 77 (47%) patients in the intervention group, and 32 of 73 patients (44%) in the control group (p = 0.51). Atrial fibrillation was detected in 23 (30%) and 29 (40%) patients in the intervention and control groups respectively. AFL was detected in 11 (14%) and 5 (7%) patients in the intervention and control groups respectively. CONCLUSIONS: Contact force-guided ablation for typical atrial flutter does not reduce recurrent atrial arrhythmia after 12-month follow-up as compared with ablation blinded for contact force.