Martin Borggrefe

Brugada Syndrome: Report of the Second Consensus Conference Endorsed by the Heart Rhythm Society and the European Heart Rhythm Association

Since its introduction as a clinical entity in 1992, the Brugada syndrome has progressed from being a rare disease to one that is second only to automobile accidents as a cause of death among young adults in some countries. Electrocardiographically characterized by a distinct ST-segment elevation in the right precordial leads, the syndrome is associated with a high risk for sudden cardiac death in young and otherwise healthy adults, and less frequently in infants and children. Patients with a spontaneously appearing Brugada ECG have a high risk for sudden arrhythmic death secondary to ventricular tachycardia/fibrillation. The ECG manifestations of Brugada syndrome are often dynamic or concealed and may be unmasked or modulated by sodium channel blockers, a febrile state, vagotonic agents, alpha-adrenergic agonists, beta-adrenergic blockers, tricyclic or tetracyclic antidepressants, a combination of glucose and insulin, hypo- and hyperkalemia, hypercalcemia, and alcohol and cocaine toxicity. In recent years, an exponential rise in the number of reported cases and a striking proliferation of articles defining the clinical, genetic, cellular, ionic, and molecular aspects of the disease have occurred. The report of the first consensus conference, published in 2002, focused on diagnostic criteria. The present report, which emanated from the second consensus conference held in September 2003, elaborates further on the diagnostic criteria and examines risk stratification schemes and device and pharmacological approaches to therapy on the basis of the available clinical and basic science data.

2014 ESC Guidelines on diagnosis and management of hypertrophic cardiomyopathy: the Task Force for the Diagnosis and Management of Hypertrophic Cardiomyopathy of the European Society of Cardiology (ESC)

2D : two-dimensional 99mTc-DPD : 99mTechnetium-3,3-diphosphono- 1,2-propanodi-carboxylic acid ACE : angiotensin-converting enzyme AF : atrial fibrillation AL : amyloid light chain AR : aortic regurgitation ARB : angiotensin receptor blocker ATTR : amyloidosis-transthyretin type AV : atrioventricular BiVAD : biventricular assist device BNP : brain natriuretic peptide BPM : Beats per minute CCS : Canadian Cardiovascular Society CFC : cardiofacialcutaneous CHA2DS2-VASc : Congestive Heart failure, hypertension, Age ≥75 (doubled), Diabetes, Stroke (doubled), Vascular disease, Age 65–74, and Sex (female) CMR : cardiac magnetic resonance CRT : cardiac resynchronization therapy CRT-D : cardiac resynchronization therapy-defibrillator CRT-P : Cardiac resynchronization therapy with a pacemaker CT : computed tomography DC : direct current DNA : deoxyribonucleic acid E/A : ratio of mitral peak velocity of early filling (E) to mitral peak velocity of late filling (A) E/e’ : ratio of early transmitral flow velocity (E) to early mitral annulus velocity (e’) EACTS : European Association for Cardio-Thoracic Surgery ECG : electrocardiogram EF : ejection fraction EPS : electrophysiological study ESC : European Society of Cardiology FDA : (US) Food and Drug Administration FHL1 : four and a half LIM domains 1 HAS-BLED : hypertension, abnormal renal/liver function, stroke, bleeding history or predisposition, labile INR, elderly (>65 years), drugs/alcohol concomitantly HCM : hypertrophic cardiomyopathy hs-cTnT : high sensitivity cardiac troponin T HTS : high throughput sequencing ICD : implantable cardioverter defibrillator ILR : implantable loop recorder INR : international normalized ratio IUD : intrauterine device LA : left atrium LAMP-2 : lysosome-associated membrane protein 2 LBBB : left bundle branch block LEOPARD : Lentigines, ECG abnormalities, Ocular hypertelorism, Pulmonary stenosis, Abnormal genitalia, Retardation of growth, and sensory-neural Deafness LGE : late gadolinium enhancement LV : left ventricular LVAD : left ventricular assist device LVH : left ventricular hypertrophy LVOTO : left ventricular outlow tract obstruction MADIT-RIT : Multicenter Automatic Defibrillator Implantation Trial—Reduce Inappropriate Therapy MAPK : mitogen activated protein kinase MELAS : mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes MERFF : myoclonic epilepsy with ragged red fibres MRA : mineralocorticoid receptor antagonist MYBPC3 : myosin-binding protein C, cardiac-type MYH7 : myosin-7 (s-myosin heavy chain) MYL3 : myosin light chain 3 NOAC : new oral anticoagulants NSVT : non-sustained ventricular tachycardia NT-proBNP : N-terminal pro brain natriuretic peptide NYHA : New York Heart Association OAC : oral anticoagulants o.d. : omni die (every day) PC-CMR : phase contrast cardiac magnetic resonance PDE5 : phosphodiesterase type 5 PET : positron emission tomography PRKAG2 : gamma-2 sub-unit of the adenosine monophosphate-activated protein kinase RAAS : renin angiotensin aldosterone system RV : right ventricular SAM : systolic anterior motion SCD : sudden cardiac death SAA : septal alcohol ablation S-ICD™ : Subcutaneous lead implantable cardioverter defibrillator SPECT : single photon emission computed tomography SSFP : steady-state free precession SVT : supraventricular tachycardia TOE : transoesophageal echocardiography TNNI3 : troponin I, cardiac muscle TNNT2 : troponin T, cardiac muscle TPM1 : tropomyosin alpha-1 chain TTE : transthoracic echocardiography TTR : transthyretin VF : ventricular fibrillation VKA : vitamin K antagonist VT : ventricular tachycardia WHO : World Health Organization Guidelines summarize and evaluate all available evidence at the time of the writing process, on a particular issue with the aim of assisting health professionals in selecting the best management strategies for an individual patient, with a given condition, taking into account the impact on outcome, as well as the risk-benefit-ratio of particular diagnostic or therapeutic means. Guidelines and recommendations should help the health professionals to make decisions in their daily practice. However, the final decisions concerning an individual patient must be made by the responsible health professional(s) in consultation with the patient and caregiver as appropriate. A great number of Guidelines have been issued in recent years by the European Society of Cardiology (ESC) as well as by other societies and organisations. Because of the impact on clinical practice, quality criteria for the development of guidelines have been established in order to make all decisions transparent to the user. The recommendations for formulating and issuing ESC Guidelines can be found on the ESC website (http://www.escardio.org/guidelines-surveys/esc-guidelines/about/Pages/rules-writing.aspx). ESC Guidelines represent the official position of the ESC on a given topic and are regularly updated. Members of this Task Force were selected by the ESC to represent professionals involved with the medical care of patients with this pathology. Selected experts in the field undertook a comprehensive review of the published evidence for management (including diagnosis, treatment, prevention and rehabilitation) of a given condition according to ESC Committee for Practice Guidelines (CPG) policy. A critical evaluation of diagnostic and therapeutic procedures was performed including assessment of the risk-benefit-ratio. Estimates of expected health outcomes for larger populations were included, where data exist. The level of evidence and the strength of recommendation of particular management options were weighed and graded according to predefined scales, as outlined in Tables 1 and 2 . The experts of …

Loss-of-Function Mutations in the Cardiac Calcium Channel Underlie a New Clinical Entity Characterized by ST-Segment Elevation, Short QT Intervals, and Sudden Cardiac Death

Background— Cardiac ion channelopathies are responsible for an ever-increasing number and diversity of familial cardiac arrhythmia syndromes. We describe a new clinical entity that consists of an ST-segment elevation in the right precordial ECG leads, a shorter-than-normal QT interval, and a history of sudden cardiac death. Methods and Results— Eighty-two consecutive probands with Brugada syndrome were screened for ion channel gene mutations with direct sequencing. Site-directed mutagenesis was performed, and CHO-K1 cells were cotransfected with cDNAs encoding wild-type or mutant CACNB2b (Cav&bgr;2b), CACNA2D1 (Cav&agr;2&dgr;1), and CACNA1C tagged with enhanced yellow fluorescent protein (Cav1.2). Whole-cell patch-clamp studies were performed after 48 to 72 hours. Three probands displaying ST-segment elevation and corrected QT intervals ≤360 ms had mutations in genes encoding the cardiac L-type calcium channel. Corrected QT ranged from 330 to 370 ms among probands and clinically affected family members. Rate adaptation of QT interval was reduced. Quinidine normalized the QT interval and prevented stimulation-induced ventricular tachycardia. Genetic and heterologous expression studies revealed loss-of-function missense mutations in CACNA1C (A39V and G490R) and CACNB2 (S481L) encoding the &agr;1- and &bgr;2b-subunits of the L-type calcium channel. Confocal microscopy revealed a defect in trafficking of A39V Cav1.2 channels but normal trafficking of channels containing G490R Cav1.2 or S481L Cav&bgr;2b-subunits. Conclusions— This is the first report of loss-of-function mutations in genes encoding the cardiac L-type calcium channel to be associated with a familial sudden cardiac death syndrome in which a Brugada syndrome phenotype is combined with shorter-than-normal QT intervals.

Sudden Death Associated With Short-QT Syndrome Linked to Mutations in HERG

Background—Sudden cardiac death takes the lives of more than 300 000 Americans annually. Malignant ventricular arrhythmias occurring in individuals with structurally normal hearts account for a subgroup of these sudden deaths. The present study describes the genetic basis for a new clinical entity characterized by sudden death and short-QT intervals in the ECG. Methods and Results—Three families with hereditary short-QT syndrome and a high incidence of ventricular arrhythmias and sudden cardiac death were studied. In 2 of them, we identified 2 different missense mutations resulting in the same amino acid change (N588K) in the S5-P loop region of the cardiac IKr channel HERG (KCNH2). The mutations dramatically increase IKr, leading to heterogeneous abbreviation of action potential duration and refractoriness, and reduce the affinity of the channels to IKr blockers. Conclusions—We demonstrate a novel genetic and biophysical mechanism responsible for sudden death in infants, children, and young adults caused by mutations in KCNH2. The occurrence of sudden cardiac death in the first 12 months of life in 2 patients suggests the possibility of a link between KCNH2 gain of function mutations and sudden infant death syndrome. KCNH2 is the binding target for a wide spectrum of cardiac and noncardiac pharmacological compounds. Our findings may provide better understanding of drug interaction with KCNH2 and have implications for diagnosis and therapy of this and other arrhythmogenic diseases.

Proposed Diagnostic Criteria for the Brugada Syndrome Consensus Report

Asyndrome characterized by ST-segment elevation in right precordial leads (V1 to V3) that is unrelated to ischemia, electrolyte disturbances, or obvious structural heart disease was reported as early as 1953,1 but was first described as a distinct clinical entity associated with a high risk of sudden cardiac death in 1992.2–4⇓⇓ The Brugada syndrome is a familial disease that displays an autosomal dominant mode of transmission, with incomplete penetrance and an incidence ranging between 5 and 66 per 10 000. In regions of Southeast Asia where it is endemic, the clinical presentation of Brugada syndrome is distinguished by a male predominance (8:1 ratio of male:female) and the appearance of arrhythmic events at an average age of 40 years (range: 1 to 77 years).2,5⇓ Although a number of candidate genes are considered plausible, thus far the syndrome has been linked only to mutations in SCN5A , the gene encoding for the α subunit of the sodium channel.6 A number of ambiguities exist concerning the diagnosis of Brugada syndrome. The electrocardiographic signature of the syndrome is dynamic and often concealed, but can be unmasked by potent sodium channel blockers such as flecainide, ajmaline, and procainamide,7 although the specificity of this effect for uncovering patients at risk for sudden death has been an issue of concern. A recent report by Remme et al8 has shown that the number of idiopathic ventricular fibrillation patients diagnosed as having Brugada syndrome is a sensitive function of the diagnostic criteria applied. What are the proper diagnostic criteria for identifying Brugada syndrome? A definitive answer to this question has been out of reach and is the reason for the establishment of a special Arrhythmia Working Group of the European Society of Cardiology that met from August 31 to …

Short QT Syndrome: a familial cause of sudden death.

Background—A prolonged QT interval is associated with a risk for life-threatening events. However, little is known about prognostic implications of the reverse—a short QT interval. Several members of 2 different families were referred for syncope, palpitations, and resuscitated cardiac arrest in the presence of a positive family history for sudden cardiac death. Autopsy did not reveal any structural heart disease. All patients had a constantly and uniformly short QT interval at ECG. Methods and Results—Six patients from both families were submitted to extensive noninvasive and invasive work-up, including serial resting ECGs, echocardiogram, cardiac MRI, exercise testing, Holter ECG, and signal-averaged ECG. Four of 6 patients underwent electrophysiological evaluation including programmed ventricular stimulation. In all subjects, a structural heart disease was excluded. At baseline ECG, all patients exhibited a QT interval ≤280 ms (QTc ≤300 ms). During electrophysiological study, short atrial and ventricular refractory periods were documented in all and increased ventricular vulnerability to fibrillation in 3 of 4 patients. Conclusions—The short QT syndrome is characterized by familial sudden death, short refractory periods, and inducible ventricular fibrillation. It is important to recognize this ECG pattern because it is related to a high risk of sudden death in young, otherwise healthy subjects.

Long-Term Prognosis of Patients Diagnosed With Brugada Syndrome Results From the FINGER Brugada Syndrome Registry

Background— Brugada syndrome is characterized by ST-segment elevation in the right precordial leads and an increased risk of sudden cardiac death (SCD). Fundamental questions remain on the best strategy for assessing the real disease-associated arrhythmic risk, especially in asymptomatic patients. The aim of the present study was to evaluate the prognosis and risk factors of SCD in Brugada syndrome patients in the FINGER (France, Italy, Netherlands, Germany) Brugada syndrome registry. Methods and Results— Patients were recruited in 11 tertiary centers in 4 European countries. Inclusion criteria consisted of a type 1 ECG present either at baseline or after drug challenge, after exclusion of diseases that mimic Brugada syndrome. The registry included 1029 consecutive individuals (745 men; 72%) with a median age of 45 (35 to 55) years. Diagnosis was based on (1) aborted SCD (6%); (2) syncope, otherwise unexplained (30%); and (3) asymptomatic patients (64%). During a median follow-up of 31.9 (14 to 54.4) months, 51 cardiac events (5%) occurred (44 patients experienced appropriate implantable cardioverter-defibrillator shocks, and 7 died suddenly). The cardiac event rate per year was 7.7% in patients with aborted SCD, 1.9% in patients with syncope, and 0.5% in asymptomatic patients. Symptoms and spontaneous type 1 ECG were predictors of arrhythmic events, whereas gender, familial history of SCD, inducibility of ventricular tachyarrhythmias during electrophysiological study, and the presence of an SCN5A mutation were not predictive of arrhythmic events. Conclusions— In the largest series of Brugada syndrome patients thus far, event rates in asymptomatic patients were low. Inducibility of ventricular tachyarrhythmia and family history of SCD were not predictors of cardiac events.

Dronedarone in high-risk permanent atrial fibrillation

BACKGROUND Dronedarone restores sinus rhythm and reduces hospitalization or death in intermittent atrial fibrillation. It also lowers heart rate and blood pressure and has antiadrenergic and potential ventricular antiarrhythmic effects. We hypothesized that dronedarone would reduce major vascular events in high-risk permanent atrial fibrillation. METHODS We assigned patients who were at least 65 years of age with at least a 6-month history of permanent atrial fibrillation and risk factors for major vascular events to receive dronedarone or placebo. The first coprimary outcome was stroke, myocardial infarction, systemic embolism, or death from cardiovascular causes. The second coprimary outcome was unplanned hospitalization for a cardiovascular cause or death. RESULTS After the enrollment of 3236 patients, the study was stopped for safety reasons. The first coprimary outcome occurred in 43 patients receiving dronedarone and 19 receiving placebo (hazard ratio, 2.29; 95% confidence interval [CI], 1.34 to 3.94; P=0.002). There were 21 deaths from cardiovascular causes in the dronedarone group and 10 in the placebo group (hazard ratio, 2.11; 95% CI, 1.00 to 4.49; P=0.046), including death from arrhythmia in 13 patients and 4 patients, respectively (hazard ratio, 3.26; 95% CI, 1.06 to 10.00; P=0.03). Stroke occurred in 23 patients in the dronedarone group and 10 in the placebo group (hazard ratio, 2.32; 95% CI, 1.11 to 4.88; P=0.02). Hospitalization for heart failure occurred in 43 patients in the dronedarone group and 24 in the placebo group (hazard ratio, 1.81; 95% CI, 1.10 to 2.99; P=0.02). CONCLUSIONS Dronedarone increased rates of heart failure, stroke, and death from cardiovascular causes in patients with permanent atrial fibrillation who were at risk for major vascular events. Our data show that this drug should not be used in such patients. (Funded by Sanofi-Aventis; PALLAS ClinicalTrials.gov number, NCT01151137.).

Chronic vagus nerve stimulation: a new and promising therapeutic approach for chronic heart failure

AIMS In chronic heart failure (CHF), reduced vagal activity correlates with increased mortality and acute decompensation. Experimentally, chronic vagus nerve stimulation (VNS) improved left ventricular (LV) function and survival; clinically, it is used for the treatment of drug-refractory epilepsy. We assessed safety and tolerability of chronic VNS in symptomatic CHF patients, using a novel implantable nerve stimulation system. The secondary goal was to obtain preliminary data on clinical efficacy. METHODS AND RESULTS This multi-centre, open-label phase II, two-staged study (8-patient feasibility phase plus 24-patient safety and tolerability phase) enrolled 32 New York Heart Association (NYHA) class II-IV patients [age 56 ± 11 years, LV ejection fraction (LVEF) 23 ± 8%]. Right cervical VNS with CardioFit (BioControl Medical) implantable system started 2-4 weeks after implant, slowly raising intensity; patients were followed 3 and 6 months thereafter with optional 1-year follow-up. Overall, 26 serious adverse events (SAEs) occurred in 13 of 32 patients (40.6%), including three deaths and two clearly device-related AEs (post-operative pulmonary oedema, need of surgical revision). Expected non-serious device-related AEs (cough, dysphonia, and stimulation-related pain) occurred early but were reduced and disappeared after stimulation intensity adjustment. There were significant improvements (P < 0.001) in NYHA class quality of life, 6-minute walk test (from 411 ± 76 to 471 ± 111 m), LVEF (from 22 ± 7 to 29 ± 8%), and LV systolic volumes (P = 0.02). These improvements were maintained at 1 year. CONCLUSIONS This open-label study shows that chronic VNS in CHF patients with severe systolic dysfunction may be safe and tolerable and may improve quality of life and LV function. A controlled clinical trial appears warranted.

Long-Term Prognosis of Individuals With Right Precordial ST-Segment–Elevation Brugada Syndrome

Background—Brugada syndrome is an arrhythmogenic disease characterized by an ECG pattern of ST-segment elevation in the right precordial leads and an increased risk of sudden cardiac death as a result of ventricular fibrillation. Controversy exists with regard to risk stratification and therapeutic management, particularly in asymptomatic individuals. Methods and Results—A total of 212 individuals (mean age, 45±6 years) with a type 1 Brugada ECG pattern were studied. Of these, 123 (58%) were asymptomatic, 65 (31%) had ≥1 syncope of unknown origin, and 24 (11%) had to be resuscitated because of ventricular fibrillation. In 125 individuals (59%), a spontaneous type 1 ECG was recorded. In the remaining, drug challenge with a class I antiarrhythmic agent unmasked a Brugada ECG. The mean ST elevation was 2.3±1.2 mm in symptomatic patients and 1.9±1.5 mm in asymptomatic individuals (P=0.04). During a mean follow-up of 40±50 months, 4 of the 24 patients (17%) with aborted sudden cardiac death and 4 of 65 (6%) with a prior syncope had a recurrent arrhythmic event, whereas only 1 of 123 asymptomatic individuals (0.8%) had a first arrhythmic event. Four of 9 patients with arrhythmic events during follow-up were not inducible during programmed electrical stimulation. A previous history of aborted sudden death or syncope and the presence of a spontaneous type 1 ECG were predictors of adverse outcome. Conclusions—The present study reports data on a large population of individuals with a type 1 Brugada ECG pattern with the longest follow-up reported so far. A very low incidence of severe arrhythmic events, particularly in asymptomatic individuals, was found during follow-up. In the presence of very few arrhythmic events on follow-up, programmed electrical stimulation showed very little accuracy in predicting outcome.