Timothy syndrome is a multisystem disorder characterized by cardiac, hand/foot, facial, and neuro... more Timothy syndrome is a multisystem disorder characterized by cardiac, hand/foot, facial, and neurodevelopmental features. The two forms are type 1 (classic) and type 2, a rare form caused by mutations in a transcript variant of the same gene. Cardiac findings include a rate-corrected QT interval of between 480 ms and 700 ms and congenital heart defects (patent ductus arteriosus, patent foramen ovale, ventricular septal defect, tetralogy of Fallot, hypertrophic cardiomyopathy). Hand/foot findings are unilateral or bilateral cutaneous syndactyly variably involving fingers two (index), three (middle), four (ring), and five (little) and bilateral cutaneous syndactyly of toes two and three. Facial findings include flat nasal bridge, low-set ears, thin upper lip, and round face. Neuropsychiatric involvement includes global developmental delays and autism spectrum disorders. Ventricular tachyarrhythmia is the leading cause of death, followed by infection and complications of intractable hyp...
In long QT syndrome (LQTS), disease severity and response to therapy vary according to the geneti... more In long QT syndrome (LQTS), disease severity and response to therapy vary according to the genetic loci. There exists a critical need to devise strategies to expedite genetic analysis. To perform genetic screening in patients with LQTS to determine the yield of genetic testing, as well as the type and the prevalence of mutations. We investigated whether the detection of a set of frequently mutated codons in the KCNQ1, KCNH2, and SCN5A genes may translate in a novel strategy for rapid efficient genetic testing of 430 consecutive patients referred to our center between June 1996 and June 2004. The entire coding regions of KCNQ1, KCNH2, SCN5A, KCNE1, and KCNE2 were screened by denaturing high-performance liquid chromatography and DNA sequencing. The frequency and the type of mutations were defined to identify a set of recurring mutations. A separate cohort of 75 consecutive probands was used as a validation group to quantify prospectively the prevalence of the recurring mutations identified in the primary LQTS population. Development of a novel approach to LQTS genotyping. We identified 235 different mutations, 138 of which were novel, in 310 (72%) of 430 probands (49% KCNQ1, 39% KCNH2, 10% SCN5A, 1.7% KCNE1, and 0.7% KCNE2). Fifty-eight percent of probands carried nonprivate mutations in 64 codons of KCNQ1, KCNH2, and SCN5A genes. A similar occurrence of mutations at these codons (52%) was confirmed in the prospective cohort of 75 probands and in previously published LQTS cohorts. We have developed an approach to improve the efficiency of genetic screening for LQTS. This novel method may facilitate wider access to genotyping resulting in better risk stratification and treatment of LQTS patients.
Long QT syndrome (LQTS) is a common inheritable arrhythmogenic disorder, often secondary to mutat... more Long QT syndrome (LQTS) is a common inheritable arrhythmogenic disorder, often secondary to mutations in the KCNQ1, KCNH2, and SCN5A genes. The disease is characterized by a prolonged ventricular repolarization (QTc interval) that confers susceptibility to life-threatening arrhythmic events (LAEs). This study sought to create an evidence-based risk stratification scheme to personalize the quantification of the arrhythmic risk in patients with LQTS. Data from 1,710 patients with LQTS followed up for a median of 7.1 years (interquartile range [IQR]: 2.7 to 13.4 years) were analyzed to estimate the 5-year risk of LAEs based on QTc duration and genotype and to assess the antiarrhythmic efficacy of beta-blockers. The relationship between QTc duration and risk of events was investigated by comparison of linear and cubic spline models, and the linear model provided the best fit. The 5-year risk of LAEs while patients were off therapy was then calculated in a multivariable Cox model with QTc and genotype considered as independent factors. The estimated risk of LAEs increased by 15% for every 10-ms increment of QTc duration for all genotypes. Intergenotype comparison showed that the risk for patients with LQT2 and LQT3 increased by 130% and 157% at any QTc duration versus patients with LQT1. Analysis of response to beta-blockers showed that only nadolol reduced the arrhythmic risk in all genotypes significantly compared with no therapy (hazard ratio: 0.38; 95% confidence interval: 0.15 to 0.93; p = 0.03). The study provides an estimator of risk of LAEs in LQTS that allows a granular estimate of 5-year arrhythmic risk and demonstrate the superiority of nadolol in reducing the risk of LAEs in LQTS.
Journal of the American College of Cardiology, Jan 13, 2016
Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a leading cause of sudden cardiac death... more Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a leading cause of sudden cardiac death, but its progression over time and predictors of arrhythmias are still being defined. This study sought to describe the clinical course of ARVC and occurrence of life-threatening arrhythmic events (LAE) and cardiovascular mortality; identify risk factors associated with increased LAE risk; and define the response to therapy. We determined the clinical course of 301 consecutive patients with ARVC using the Kaplan-Meier method adjusted to avoid the bias of delayed entry. Predictors of LAE over 5.8 years of follow-up were determined with Cox multivariable analysis. Treatment efficacy was assessed comparing LAE rates during matched time intervals. A first LAE occurred in 1.5 per 100 person-years between birth and age 20 years, in 4.0 per 100 person-years between ages 21 and 40 years, and in 2.4 per 100 person-years between ages 41 and 60 years. Cumulative probability of a first LAE at follo...
Timothy syndrome is a multisystem disorder characterized by cardiac, hand/foot, facial, and neuro... more Timothy syndrome is a multisystem disorder characterized by cardiac, hand/foot, facial, and neurodevelopmental features. The two forms are type 1 (classic) and type 2, a rare form caused by mutations in a transcript variant of the same gene. Cardiac findings include a rate-corrected QT interval of between 480 ms and 700 ms and congenital heart defects (patent ductus arteriosus, patent foramen ovale, ventricular septal defect, tetralogy of Fallot, hypertrophic cardiomyopathy). Hand/foot findings are unilateral or bilateral cutaneous syndactyly variably involving fingers two (index), three (middle), four (ring), and five (little) and bilateral cutaneous syndactyly of toes two and three. Facial findings include flat nasal bridge, low-set ears, thin upper lip, and round face. Neuropsychiatric involvement includes global developmental delays and autism spectrum disorders. Ventricular tachyarrhythmia is the leading cause of death, followed by infection and complications of intractable hyp...
In long QT syndrome (LQTS), disease severity and response to therapy vary according to the geneti... more In long QT syndrome (LQTS), disease severity and response to therapy vary according to the genetic loci. There exists a critical need to devise strategies to expedite genetic analysis. To perform genetic screening in patients with LQTS to determine the yield of genetic testing, as well as the type and the prevalence of mutations. We investigated whether the detection of a set of frequently mutated codons in the KCNQ1, KCNH2, and SCN5A genes may translate in a novel strategy for rapid efficient genetic testing of 430 consecutive patients referred to our center between June 1996 and June 2004. The entire coding regions of KCNQ1, KCNH2, SCN5A, KCNE1, and KCNE2 were screened by denaturing high-performance liquid chromatography and DNA sequencing. The frequency and the type of mutations were defined to identify a set of recurring mutations. A separate cohort of 75 consecutive probands was used as a validation group to quantify prospectively the prevalence of the recurring mutations identified in the primary LQTS population. Development of a novel approach to LQTS genotyping. We identified 235 different mutations, 138 of which were novel, in 310 (72%) of 430 probands (49% KCNQ1, 39% KCNH2, 10% SCN5A, 1.7% KCNE1, and 0.7% KCNE2). Fifty-eight percent of probands carried nonprivate mutations in 64 codons of KCNQ1, KCNH2, and SCN5A genes. A similar occurrence of mutations at these codons (52%) was confirmed in the prospective cohort of 75 probands and in previously published LQTS cohorts. We have developed an approach to improve the efficiency of genetic screening for LQTS. This novel method may facilitate wider access to genotyping resulting in better risk stratification and treatment of LQTS patients.
Long QT syndrome (LQTS) is a common inheritable arrhythmogenic disorder, often secondary to mutat... more Long QT syndrome (LQTS) is a common inheritable arrhythmogenic disorder, often secondary to mutations in the KCNQ1, KCNH2, and SCN5A genes. The disease is characterized by a prolonged ventricular repolarization (QTc interval) that confers susceptibility to life-threatening arrhythmic events (LAEs). This study sought to create an evidence-based risk stratification scheme to personalize the quantification of the arrhythmic risk in patients with LQTS. Data from 1,710 patients with LQTS followed up for a median of 7.1 years (interquartile range [IQR]: 2.7 to 13.4 years) were analyzed to estimate the 5-year risk of LAEs based on QTc duration and genotype and to assess the antiarrhythmic efficacy of beta-blockers. The relationship between QTc duration and risk of events was investigated by comparison of linear and cubic spline models, and the linear model provided the best fit. The 5-year risk of LAEs while patients were off therapy was then calculated in a multivariable Cox model with QTc and genotype considered as independent factors. The estimated risk of LAEs increased by 15% for every 10-ms increment of QTc duration for all genotypes. Intergenotype comparison showed that the risk for patients with LQT2 and LQT3 increased by 130% and 157% at any QTc duration versus patients with LQT1. Analysis of response to beta-blockers showed that only nadolol reduced the arrhythmic risk in all genotypes significantly compared with no therapy (hazard ratio: 0.38; 95% confidence interval: 0.15 to 0.93; p = 0.03). The study provides an estimator of risk of LAEs in LQTS that allows a granular estimate of 5-year arrhythmic risk and demonstrate the superiority of nadolol in reducing the risk of LAEs in LQTS.
Journal of the American College of Cardiology, Jan 13, 2016
Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a leading cause of sudden cardiac death... more Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a leading cause of sudden cardiac death, but its progression over time and predictors of arrhythmias are still being defined. This study sought to describe the clinical course of ARVC and occurrence of life-threatening arrhythmic events (LAE) and cardiovascular mortality; identify risk factors associated with increased LAE risk; and define the response to therapy. We determined the clinical course of 301 consecutive patients with ARVC using the Kaplan-Meier method adjusted to avoid the bias of delayed entry. Predictors of LAE over 5.8 years of follow-up were determined with Cox multivariable analysis. Treatment efficacy was assessed comparing LAE rates during matched time intervals. A first LAE occurred in 1.5 per 100 person-years between birth and age 20 years, in 4.0 per 100 person-years between ages 21 and 40 years, and in 2.4 per 100 person-years between ages 41 and 60 years. Cumulative probability of a first LAE at follo...
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Papers by Raffaella Bloise