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- Casteigt, Benjamin, et al.
(författare)
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Atrial arrhythmias and patient-reported outcomes in adults with congenital heart disease : An international study
- 2021
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Ingår i: Heart Rhythm. - : Elsevier BV. - 1547-5271 .- 1556-3871. ; 18:5, s. 793-800
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Tidskriftsartikel (refereegranskat)abstract
- Background Atrial arrhythmias (ie, intra-atrial reentrant tachycardia and atrial fibrillation) are a leading cause of morbidity and hospitalization in adults with congenital heart disease (CHD). Little is known about their effect on quality of life and other patient-reported outcomes (PROs) in adults with CHD. Objective The purpose of this study was to assess the impact of atrial arrhythmias on PROs in adults with CHD and explore geographic variations. Methods Associations between atrial arrhythmias and PROs were assessed in a cross-sectional study of adults with CHD from 15 countries spanning 5 continents. A propensity-based matching weight analysis was performed to compare quality of life, perceived health status, psychological distress, sense of coherence, and illness perception in patients with and those without atrial arrhythmias. Results A total of 4028 adults with CHD were enrolled, 707 (17.6%) of whom had atrial arrhythmias. After applying matching weights, patients with and those without atrial arrhythmias were comparable with regard to age (mean 40.1 vs 40.2 years), demographic variables (52.5% vs 52.2% women), and complexity of CHD (15.9% simple, 44.8% moderate, and 39.2% complex in both groups). Patients with atrial arrhythmias had significantly worse PRO scores with respect to quality of life, perceived health status, psychological distress (ie, depression), and illness perception. A summary score that combines all PRO measures was significantly lower in patients with atrial arrhythmias (-3.3%; P = .0006). Differences in PROs were consistent across geographic regions. Conclusion Atrial arrhythmias in adults with CHD are associated with an adverse impact on a broad range of PROs consistently across various geographic regions.
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- Gold, Michael R, et al.
(författare)
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Impact of atrial prevention pacing on atrial fibrillation burden: primary results of the Study of Atrial Fibrillation Reduction (SAFARI) trial.
- 2009
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Ingår i: Heart rhythm : the official journal of the Heart Rhythm Society. - : Elsevier BV. - 1556-3871. ; 6:3, s. 295-301
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The role of atrial-based pacing algorithms in preventing atrial fibrillation (AF) remains controversial. The inconsistent results noted in previous trials may be due in part to differences in endpoints, pacing algorithms, and study design. SAFARI, a worldwide, prospective, randomized clinical trial, was designed to address these issues and to evaluate the safety and efficacy of a suite of prevention pacing therapies (PPTs) among patients with paroxysmal AF. METHODS AND RESULTS: Patients who met standard pacemaker indications and documented symptomatic AF were implanted with a pacemaker (Vitatron Selection 9000). At 4 months, only patients with documented AF despite dual-chamber pacing were randomized to PPTs ON or PPTs OFF and followed for 6 months. Incidence of permanent AF and change in AF burden were compared between the two groups. Among the 555 patients enrolled, 240 had AF burden at 4 months and were randomized. The risk of developing permanent AF was similar in both groups (0 in the PPTs ON group vs. 3 in the OFF group). However, there was a significant reduction in AF burden between baseline and 10-month follow-up in the ON group compared with the OFF group (median decrease of 0.08 hours/day vs no change, P = .03). CONCLUSION: Among patients with paroxysmal AF and standard bradycardia indications, PPTs are safe and associated with less AF burden compared with conventional pacing.
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- Hill, JA, et al.
(författare)
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Medical misinformation: Vet the message!
- 2019
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Ingår i: Heart rhythm. - : Elsevier BV. - 1556-3871 .- 1547-5271. ; 16:3, s. 332-333
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 21. |
- Kesek, Milos, et al.
(författare)
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Increased risk of late pacemaker implantation after ablation for atrioventricular nodal reentry tachycardia : A 10-year follow-up of a nationwide cohort
- 2019
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Ingår i: Heart Rhythm. - : Elsevier. - 1547-5271 .- 1556-3871. ; 16:8, s. 1182-1188
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Tidskriftsartikel (refereegranskat)abstract
- Background: Catheter ablation of the slow pathway is the standard treatment of atrioventricular nodal reentry tachycardia (AVNRT) with a well described low risk of periprocedural atrioventricular block. Less is known about the risk of pacemaker implantation late after ablation.Objective: We aimed to quantify the risk of late pacemaker implantation in a countrywide cohort undergoing first-time ablation for AVNRT.Methods: All patients undergoing first-time ablation for AVNRT in Sweden from 2004 to 2014 were identified from the Swedish catheter ablation registry and matched against the Swedish Pacemaker and ICD registry. The cohort was compared to patients ablated for an accessory pathway (AP) and to matched controls.Results: During follow-up of 2039 days, pacemaker was implanted later than 30 days after ablation in 96 of 6842 patients with AVNRT (1.4%), 29 of 4065 patients with AP (0.7%) (P = .001), and 124 of 33,270 controls (0.4%) (P < .00001). A periprocedural pacemaker (≤30 days postablation) was implanted in 32 of 6877 patients with AVNRT (0.5%) and 9 of 4079 patients with AP (0.2%) (P = .05). With cryoablation, 5 patients needed periprocedural pacemaker implantation. Pacemakers were implanted before ablation in 88 of 6977 patients with AVNRT (1.3%) and 11 of 4100 patients with AP (0.3%); the prevalence of pacemaker implants in controls was 124 of 33,270 (0.4%) (P < .00001 for both comparisons).Conclusion: The risk of late pacemaker implantation after AVNRT ablation was low but 3 times higher than that in the control population and 3 times higher than the risk of periprocedural pacemaker implantation. Similar results were observed with cryoablation and radiofrequency ablation. Ablation may not be the cause of increased late pacemaker implantation risk.
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- Lévesque, Valérie, et al.
(författare)
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Implantable Cardioverter-Defibrillators and Patient-Reported Outcomes in Adults with Congenital Heart Disease : an International Study
- 2020
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Ingår i: Heart Rhythm. - : Elsevier BV. - 1547-5271 .- 1556-3871. ; 17:5, s. 768-776
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Implantable cardioverter-defibrillators (ICDs) are increasingly used to prevent sudden deaths in the growing population of adults with congenital heart disease (CHD). Yet, little is known about their impact on patient-reported outcomes (PROs).OBJECTIVE: We assessed and compared PROs in adults with CHD with and without ICDs.METHODS: A propensity-based matching weight analysis was conducted to evaluate PROs in an international cross-sectional study of adults with CHD from 15 countries across 5 continents.RESULTS: A total of 3,188 patients were included: 107 with ICDs and 3,081 weight-matched controls without ICDs. ICD recipients averaged 40.1±12.4 years of age, with >95% having moderate or complex CHD. Defibrillators were implanted for primary and secondary prevention in 38.3% and 61.7%, respectively. Perceived health status, psychological distress, sense of coherence, and health behaviours did not differ significantly in patients with and without ICDs. However, ICD recipients had a more threatening view of their illness (relative % difference 8.56, P=0.011). Those with secondary compared to primary prevention indications had a significantly lower quality of life score (linear analogue scale 72.0±23.1 versus 79.2±13.0, P=0.047). Marked geographic variations were observed. Overall sense of well-being, assessed by a summary score that combines various PROs, was significantly lower in ICD recipients (versus controls) from Switzerland, Argentina, Taiwan, and USA.CONCLUSIONS: In an international cohort of adults with CHD, ICDs were associated with a more threatening illness perception, with a lower quality of life in those with secondary compared to primary prevention indications. However, marked geographic variability in PROs was observed.
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- Liuba, Ioan, et al.
(författare)
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Scar progression in patients with nonischemic cardiomyopathy and ventricular arrhythmias
- 2014
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Ingår i: Heart Rhythm. - : Elsevier. - 1547-5271 .- 1556-3871. ; 11:5, s. 755-762
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND Disease progression in patients with nonischemic cardiomyopathy (NICM) is poorly understood. OBJECTIVE To assess left ventricular(LV) scar progression and dilatation by using endocardial electroanatomic mapping. METHODS We studied 13 patients with NICM and recurrent ventricular tachycardia. Two detailed sinus rhythm endocardial voltage maps(265 +/- 122 points/map) were obtained after a mean of 32 months(range 9-77 months). The scar area, defined by low bipolar (BI; less than 1.5 mV) and unipolar(UNI; less than 8.3 mV) endocardial voltage, and the LV volume were measured and compared. A scar difference of greater than 6% of the LV surface and an increase in LV volume of greater than= 20 mL were considered beyond measurement error. RESULTS Six (46%) patients had an increase in scar area beyond boundaries of prior ablation. Five patients had an increase in UNI and 1 patient had an increase in both BI and UNI areas. The increase in BI area represented 16% and the increase in UNI area represented 6.5%-46.2% of the LV surface. A significant decrease in LV ejection fraction was found only in patients with scar progression (from 39% +/- 8%:p = .0003) (LV volume increase ranging between 9% and 23%) was noted in 3 patients, all of whom had scar progression. CONCLUSIONS Progressive scarring with an increase in the area of UNI and less commonly BI electrogram abnormality is seen in 46% of the patients with NICM and ventricular tachycardia and is associated with LV dilatation and decrease in LV ejection fraction. The prominent UNI abnormality suggests predominantly midmyo-cardial or epicardial scarring.
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- Mehta, Vishal S., et al.
(författare)
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Machine learning-derived major adverse event prediction of patients undergoing transvenous lead extraction : Using the ESC EHRA EORP European lead extraction ConTRolled ELECTRa registry
- 2022
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Ingår i: Heart Rhythm. - : Elsevier. - 1547-5271 .- 1556-3871. ; 19:6, s. 885-893
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND Transvenous lead extraction (TLE) remains a high-risk procedure. OBJECTIVE The purpose of this study was to develop a machine learning (ML)-based risk stratification system to predict the risk of major adverse events (MAEs) after TLE. A MAE was defined as procedure-related major complication and procedure-related death. METHODS We designed and evaluated an ML-based risk stratification system trained using the European Lead Extraction ConTRolled (ELECTRa) registry to predict the risk of MAEs in 3555 patients undergoing TLE and tested this on an independent registry of 1171 patients. ML models were developed, including a self-normalizing neural network (SNN), stepwise logistic regression model ("stepwise model"), support vector machines, and random forest model. These were compared with the ELECTRa Registry Outcome Score (EROS) for MAEs. RESULTS There were 53 MAEs (1.7%) in the training cohort and 24 (2.4%) in the test cohort. Thirty-two clinically important features were used to train the models. ML techniques were similar to EROS by balanced accuracy (stepwise model: 0.74 vs EROS: 0.70) and superior by area under the curve (support vector machines: 0.764 vs EROS: 0.677). The SNN provided a finite risk for MAE and accurately identified MAE in 14 of 169 "high (<80%) risk" patients (8.3%) and no MAEs in all 198 "low (,20%) risk" patients (100%). CONCLUSION ML models incrementally improved risk prediction for identifying those at risk of MAEs. The SNN has the additional advantage of providing a personalized finite risk assessment for patients. This may aid patient decision making and allow better preoperative risk assessment and resource allocation.
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| 30. |
- Odenstedt, Jacob, 1968, et al.
(författare)
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Spinal cord stimulation effects on myocardial ischemia, infarct size, ventricular arrhythmia, and noninvasive electrophysiology in a porcine ischemia-reperfusion model.
- 2011
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Ingår i: Heart Rhythm. - : Elsevier BV. - 1556-3871 .- 1547-5271. ; Jan:18
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Susceptibility to ventricular arrhythmias and sudden cardiac death can be reduced by modulation of autonomic tone. Spinal cord stimulation (SCS) presumably affects autonomic tone and reduces myocardial ischemia. OBJECTIVE: The purpose of this study was to investigate whether SCS could reduce myocardial ischemia, infarct size, and ventricular arrhythmias as well as repolarization alterations in a porcine ischemia-reperfusion model. METHODS: Anesthetized common Landrace pigs were randomized to SCS (n = 10) or sham treatment (n = 10) before, during, and after 45 minutes of coronary occlusion. Area at risk, infarct size, and spontaneous ventricular arrhythmias were analyzed. Continuous three-dimensional vectorcardiograms was recorded and analyzed with respect to ECG intervals, ST-segment, and T-vector and T-vector-loop morphology. RESULTS: SCS was associated with significantly (P <.04) fewer episodes of nonsustained ventricular tachycardia (NSVT) and sustained ventricular tachycardia (SVT), particularly during mid-left anterior descending artery (LAD) occlusion (SCS vs non-SCS; NSVT, mid- and proximal LAD: 0 vs 22 and 45 vs 72; SVT, mid- and proximal LAD: 3 vs 15 and 5 vs 5). No difference in ventricular fibrillation episodes was observed. The SCS group had significantly less ST elevation (P <.03) but similar area at risk, infarct size, and ratio of infarct size/area at risk. Ischemia induced increases of T(amplitude) and T(area) suggesting increased repolarization gradients, which were significantly reduced by SCS (P <.01 for both). CONCLUSION: SCS appears to have an antiarrhythmic effect on spontaneous NSVT and SVT during ischemia-reperfusion in association with a reduction of repolarization alterations. Vectorcardiography signs of myocardial ischemia were reduced by SCS, but this intervention was not accompanied by any effect on infarct size.
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- Sahlén, Anders, et al.
(författare)
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Cardiac fatigue in long-distance runners is associated with ventricular repolarization abnormalities.
- 2009
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Ingår i: Heart rhythm : the official journal of the Heart Rhythm Society. - : Elsevier BV. - 1556-3871 .- 1547-5271. ; 6:4, s. 512-9
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Prolonged exercise can induce cardiac fatigue, which is characterized by biomarker release and impaired myocardial function. The impact on ventricular electrophysiology is largely unknown. OBJECTIVE: The objective of this study was to examine changes in ventricular repolarization after a 30-km cross-country race in runners aged >or=55 years. METHODS: Fifteen healthy participants (62 +/- 5 years) were assessed using biomarkers (N-terminal pro-brain natriuretic peptide [NT-proBNP], troponin T [TnT]), tissue Doppler echocardiography, and vectorcardiography at baseline, within 1 hour postrace and on days 1 and 6 postrace. RESULTS: During the race, NT-proBNP increased from 42 ng/L (interquartile range 25-117) to 187 ng/L (113-464), and TnT increased from undetectable levels to 0.03 microg/L (0.015-0.05). Global strain (19.1% +/- 2.2%) decreased on day 1 (17.2% +/- 1.8%) and day 6 (17.9% +/- 1.5%; P <.01). QT(c) increased from 431 +/- 15 ms prerace to 445 +/- 22 ms postrace and 445 +/- 15 ms on day 1 (P <.05), mainly because of an increased T(peak-end) interval (prerace 108 +/- 13 ms, postrace 127 +/- 43 ms, day 1 127 +/- 43 ms; P <.05). Postrace, T(area) (baseline 75 +/- 26 microVs) peaked on day 1 (105 +/- 42 microVs) and remained high on day 6 (89 +/- 37 microVs; P <.05). Runners with higher baseline NT-proBNP developed greater impairment of myocardial velocities (rho = -0.68 to -0.54; P <.05) and a larger increase in T(area) (rho = 0.73; P <.01). CONCLUSION: Cardiac fatigue induced by prolonged exertion is associated with sustained abnormalities in ventricular repolarization. Runners with higher baseline NT-proBNP are especially liable to such alterations of cardiac function.
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| 33. |
- Schwieler, J H, et al.
(författare)
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Reentry in an accessory atrioventricular pathway as a trigger for atrial fibrillation initiation in manifest Wolff-Parkinson-White syndrome: A matter of reflection?
- 2008
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Ingår i: Heart rhythm : the official journal of the Heart Rhythm Society. - : Elsevier BV. - 1556-3871 .- 1547-5271. ; 5:9, s. 1238-47
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Patients with an accessory pathway (AP) have an increased propensity to develop atrial fibrillation (AF), but the mechanism is unknown. OBJECTIVE: The purpose of this study was to identify crucial risk factors and to test the hypothesis that reflection and/or microreentry of atrial impulses propagating into the AP triggers AF. METHODS: Five hundred thirty-four patients successfully treated with radiofrequency ablation of AP at two university hospitals were evaluated. Patients were separated into those with concealed vs those with manifest AP in terms of their propensity to develop AF. To investigate AF triggering mechanisms, linear and branched two-dimensional models of atrium-to-ventricle propagation across a heterogeneous 1 x 6 AP using human ionic kinetics were simulated. RESULTS: A history of AF was twice as common in patients with manifest AP vs concealed AP irrespective of AP location. AF was more likely to occur in older males and in patients with larger atria. There was no correlation between AF history and AP refractory measures. However, the electrophysiologic properties of APs seemed to fulfill the prerequisites for reflection and/or microreentry of atrially initiated impulses. In the linear AP model, repetitive atrial stimulation resulted in progressively larger delay of atrium-to-ventricle propagation across the passive segment. Eventually, sufficient time for repolarization of the atrial segment allowed for reflection of an impulse that activated the entire atrium and by wavefront-wavetail interaction with a new atrial stimulus AF reentry was initiated. Simulations using the branched model showed that microreentry at the ventricular insertion of the AP could also initiate AF via retrograde atrial activation as a result of unidirectional block at the AP-ventricle junction. CONCLUSION: Propensity for AF in patients with an AP is strongly related to preexcitation, larger atria, male gender, and older age. Reflection and microreentry at the AP may be important for AF initiation in patients with manifest (preexcited) Wolff-Parkinson-White syndrome. Similar mechanisms also may trigger AF in patients without an AP.
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| 34. |
- Siotis, Alexander, et al.
(författare)
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LONG-TERM ADHERENCE TO FLECAINIDE AS A RHYTHM CONTROL THERAPY IN RECURRENT ATRIAL FIBRILLATION - A RETROSPECTIVE COHORT STUDY
- 2022
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Ingår i: Heart Rhythm. - : Elsevier BV. - 1556-3871 .- 1547-5271. ; 19:5, s. 315-316
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Konferensbidrag (refereegranskat)abstract
- Background: The choice of rhythm control drugs for recurrent atrial fibrillation (AF) remains empirical and is based on the safety profile rather than predicted efficacy. Flecainide is recommended for prevention of AF recurrence in patients without structural heart disease however predictors of treatment success are insufficiently studied. Objective: To assess clinical characteristics associated with flecainide treatment success in patients with recurrent AF. Methods: Using hospital medical records, 135 consecutive adult AF patients who were referred for in-hospital initiation of flecainide were included (median age 62 (IQR 53-70) years, 35% females, 28% persistent AF, median CHA2DS2-VASc score 1, median follow up time 14.5 (IQR 3.3-32.7) months). Patient characteristics at admission, including left atrial enlargement (LAE) assessed as LA volume index >34 ml/m2, were retrieved from medical records. Kaplan Meier curve and Cox regression analysis were used to analyse the association between the clinical characteristics and the likelihood of the drug discontinuation due to failed rhythm control efficacy (primary endpoint) or discontinuation for any reason (secondary endpoint). Results: By the end of follow up 88 patients (65.0%) had continued flecainide therapy. Reasons for discontinuation were failed efficacy (16.0%), side effects (7.0%) or safety issues (16.0 %) such as proarrhythmia (6.7%), heart failure (2.2%), coronary heart disease (1.5%), QRS widening (1.5%), QTc ≥500 ms (0.7%) or AV block II (0.7%). Age ≥60 years, male gender, height and LAE were significant predictors of therapy discontinuation in the univariate analysis, however only LAE (HR=3.9 95% CI 1.1-13.5 for the primary (Figure A) and HR=2.5 95%CI 1.3-4.9 for the secondary endpoints) and age ≥60 years (HR=3.9 95% CI 1.1-11.9 for the primary and HR=2.2 95%CI 1.1-4.3 for the secondary endpoint) remained independent predictors of therapy discontinuation in the multivariate analysis. The outcome did not differ between paroxysmal and persistent AF (Figure B). [Formula presented] [Formula presented] Conclusion: LAE and age ≥60 years were associated with flecainide rhythm control failure in patients with recurrent AF. The vast majority of all treatment failures occured within 6 months from the treatment start. AF type did not significantly predict treatment efficacy.
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| 35. |
- Squara, Fabien, et al.
(författare)
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Electrical connection between ipsilateral pulmonary veins : prevalence and implications for ablation and adenosine testing.
- 2015
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Ingår i: Heart Rhythm. - : Elsevier BV. - 1547-5271 .- 1556-3871. ; 12:2, s. 275-82
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Anatomic studies have reported the presence of shared myocardial fibers between approximately half of ipsilateral pulmonary veins (IPVs).OBJECTIVE: The purpose of this study was to assess the prevalence of electrical connection between IPVs and the impact of antral isolation with or without carina ablation on IPV connection.METHODS: Thirty consecutive patients undergoing atrial fibrillation (AF) ablation (14 redo) were included. Wide antral pulmonary vein isolation (PVI) was performed with or without carina lesions. For each PV set, IPV electrical connection was assessed before and after PVI by pacing and recording from the ostium of both IPVs using a circular mapping catheter and the ablation catheter. Adenosine was given after PVI to assess for acute PV reconnection.RESULTS: Before PVI without preceding AF ablation procedure, all the PVs had ipsilateral connection albeit frequently via the left atrium. After PVI, 65.6% of the IPVs were connected without carina ablation vs 17.7% if prior carina ablation (P = .001). Left vs right IPVs were connected in 57.1% and 72.2% of the cases without carina ablation, respectively, vs 30% and 0% of cases with carina ablation (P = .19 and P = .001). When transient PV reconnection was demonstrated during adenosine challenge, connected IPVs uniformly demonstrated simultaneous reconnection.CONCLUSION: Electrical connection between IPVs is uniformly demonstrated before any ablation. Two-thirds of the IPVs are connected after antral PVI, and carina ablation decreases IPV connection. Connected IPVs consistently show the same response to adenosine challenge; therefore, a single catheter positioned in either of the IPVs with electrical connection is sufficient to confirm reconnection in both veins.
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| 36. |
- Vahedi, Farzad, et al.
(författare)
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Instability of repolarization in LQTS mutation carriers compared to healthy control subjects assessed by vectorcardiography
- 2013
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Ingår i: Heart Rhythm. - : Elsevier BV. - 1547-5271 .- 1556-3871. ; 10:8, s. 1169-1175
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND Potassium channel dysfunction in congenital and acquired forms of long QT syndrome types 1 and 2 (LQT1 and LQT2) increases the beat-to-beat variability of the (IT interval. OBJECTIVE To study about the little known variability (instability) of other aspects of ventricular repolarization (VR) in humans by using vectorcardiography. METHODS Beat-to-beat analysis was performed regarding vectorcardiography derived RR, QRS, and QT intervals, as well as T vector- and T vector loop-based parameters during 1-minute recordings of uninterrupted sinus rhythm at rest in 41 adult LQT1 (n = 31) and LQT2 (n = 10) mutation carriers and 41 age- and sex-matched control subjects. The short-term variability for each parameter, describing the mean orthogonal distance to the line of identity on the Poincare plot, was calculated. RESULTS Mutation carriers showed significantly larger (by a factor 2) instability in most VR parameters compared to controls despite higher instantaneous heart rate variability (STVRR) in the control group. The longer the (IT interval, the greater was its instability, and the instability of VR dispersion measures. CONCLUSIONS A greater instability of most aspects of VR already at rest seems to be a salient feature in both LQT1 and LQT2, which might pave the way for early afterdepolarizations and torsades de pointes ventricular tachycardia. In contrast, no signs of increased VR dispersion per se were observed in mutation carriers.
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| 40. |
- Winbo, Annika, 1978-, et al.
(författare)
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Origin of the Swedish long QT syndrome Y111C/KCNQ1 founder mutation
- 2011
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Ingår i: Heart Rhythm. - : Elsevier. - 1547-5271 .- 1556-3871. ; 8:4, s. 541-547
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The Y111C/KCNQ1 mutation causes a dominant-negative effect in vitro albeit a benign clinical phenotype in a Swedish Long QT Syndrome population.OBJECTIVE: To investigate the origin (genealogic, geographic, genetic and age) of the Y111C/KCNQ1 mutation in Sweden.METHODS: We identified 170 carriers of the Y111C/KCNQ1 mutation in 37 Swedish proband families. Genealogical investigation was performed in all families. Haplotype analysis was performed in 26 probands, 21 family members and 84 healthy Swedish controls, using 15 satellite markers flanking the KCNQ1 gene. Mutation age was estimated using the ESTIAGE and DMLE computer softwares and regional population demographics data.RESULTS: All probands were traced back to a northern river valley region. A founder couple born in 1605/1614 connected 26/37 families. Haplotyped probands shared 2-14 (median 10) uncommon alleles, with frequencies ranging between 0.01-0.41 (median 0.16) in the controls. The age of the mutation was estimated to 24 generations (95% CI 18; 34), i.e. 600 years (95% CI 450; 850) if assuming 25 years per generation. The number of now living Swedish Y111C mutation-carriers was estimated to ~200-400 individuals for the mutation age span 22-24 generations and population growth rates 25-27%.CONCLUSIONS: The Y111C/KCNQ1 mutation is a Swedish LQTS founder mutation, introduced in the northern population approximately 600 years ago. The enrichment of the mutation was enabled by a mild clinical phenotype and strong regional founder effects during the population development of the northern inland. The Y111C/KCNQ1 founder population constitutes an important asset for future genetic and clinical studies.
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