Programmed Ventricular Stimulation for Risk Stratification in the Brugada Syndrome: A Pooled Analysis.

BACKGROUND: The role of programmed ventricular stimulation in identifying patients with Brugada syndrome at the highest risk for sudden death is uncertain. METHODS AND RESULTS: We performed a systematic review and pooled analysis of prospective, observational studies of patients with Brugada syndrome without a history of sudden cardiac arrest who underwent programmed ventricular stimulation. We estimated incidence rates and relative hazards of cardiac arrest or implantable cardioverter-defibrillator shock. We analyzed individual-level data from 8 studies comprising 1312 patients who experienced 65 cardiac events (median follow-up, 38.3 months). A total of 527 patients were induced into arrhythmias with up to triple extrastimuli. Induction was associated with cardiac events during follow-up (hazard ratio, 2.66; 95% confidence interval [CI], 1.44-4.92, P<0.001), with the greatest risk observed among those induced with single or double extrastimuli. Annual event rates varied substantially by syncope history, presence of spontaneous type 1 ECG pattern, and arrhythmia induction. The lowest risk occurred in individuals without syncope and with drug-induced type 1 patterns (0.23%, 95% CI, 0.05-0.68 for no induced arrhythmia with up to double extrastimuli; 0.45%, 95% CI, 0.01-2.49 for induced arrhythmia), and the highest risk occurred in individuals with syncope and spontaneous type 1 patterns (2.55%, 95% CI, 1.58-3.89 for no induced arrhythmia; 5.60%, 95% CI, 2.98-9.58 for induced arrhythmia). CONCLUSIONS: In patients with Brugada syndrome, arrhythmias induced with programmed ventricular stimulation are associated with future ventricular arrhythmia risk. Induction with fewer extrastimuli is associated with higher risk. However, clinical risk factors are important determinants of arrhythmia risk, and lack of induction does not necessarily portend low ventricular arrhythmia risk, particularly in patients with high-risk clinical features.

Permanent pacing after transcatheter aortic valve implantation of a CoreValve prosthesis as determined by electrocardiographic and electrophysiological predictors: a single-centre experience.

AIM: The most frequent conduction complications with transcatheter aortic valve implantation (TAVI) are complete atrioventricular (AV) block and new bundle branch block (BB). The purpose of this study was to assess clinical, electrocardiographic, and electrophysiological predictors of conduction abnormalities in patients (pts) undergoing TAVI with the CoreValve prosthesis. The secondary end points were the long-term rhythm follow-up and the recovery of conduction. METHODS AND RESULTS: Forty-five consecutive pts with severe aortic stenosis, New York Heart Association II/III, and normal or slightly impaired left ventricular function who underwent CoreValve transcatheter implantation were randomized 2:1 to electrocardiographic and electrocardiographic plus electrophysiological evaluations. Pacemakers were implanted in pts with complete AV block. Follow-up was performed at 1, 6, 12, and 24 months. Conduction was affected in the total group of pts undergoing TAVI. The PR lengthened compared with the baseline but did not exceed the normal cut-off of 200 ms, and the QRS widened, basically due to new left bundle branch blocks (LBBBs). Within 1 month of follow-up, 10 pts (22%) developed complete AV block (9 peri-procedurally-20%) and 15 pts (33%) developed a new bundle BB, with LBBBs being the most common (14-31%). In the 30 pts who underwent an electrophysiological study, analysis showed that prolonged HV intervals were prognostic for pacemaker implantation. Follow-up in the total study group revealed that only 4 of the 10 (9%) initial implantations remained completely pacemaker dependent. CONCLUSION: Conduction was affected in all pts undergoing TAVI, but serious complications that required permanent pacing generally occurred in pts with pre-existing conduction abnormalities.

The pathophysiological relationship and clinical significance of left atrial function and left ventricular diastolic dysfunction in ß-thalassemia major.

Iron deposition in combination with inflammatory and immunogenetic factors is involved in the pathophysiology of cardiac dysfunction in ß-thalassemia major. We investigated the mechanical and endocrine function of the left atrium and ventricle to identify early signs of dysfunction. We studied 90 patients (mean age: 29 ± 11 years) with ß-thalassemia and normal left ventricular function and 90 age and sex-matched healthy controls. Patients and controls underwent a thorough cardiac echocardiographic study and measurements of the b-type (NT-proBNP) and atrial natriuretic peptides (proANP). Patients underwent 24-hr Holter recordings for arrhythmia monitoring. In the patient group, atria were affected early during the course of the disease, prior to diastolic and systolic left ventricular dysfunction. The E/E'ratio (E Doppler mitral fast inflow to the corresponding tissue Doppler E) continually increased with age (P < 0.05) and reached levels indicating left ventricular diastolic dysfunction (E/E' > 15) in the third decade whereas indexes of active and passive atrial function decreased gradually throughout life. In controls, the E/E' ratio continually increased with age but with later (fifth decade) appearance of diastolic dysfunction and a compensatory increase in atrial active function. Both natriuretic peptides were significantly increased in patients compared to controls (558 ± 141 and 2,580 ± 1,830 fmol/mL for NT-proBNP and proANP versus 332 ± 106 and 1,331 ± 1,134 fmol/mL, respectively). Atrial fibrillation was found in a subgroup of 23 (26%) patients, older in age with mild diastolic function and enlarged, depressed atria. In conclusion, atrial mechanical depression seems to be a very early sign of cardiac damage. It may become echocardiographically evident even before diastolic and systolic dysfunction and is associated to supraventricular arrhythmias.

Diagnostic yield of implantable loop recorders: Results from the Hellenic registry.

AIMS: Implantable loop recorders (ILRs) are increasingly being used for long-term cardiac monitoring in different clinical settings. The aim of this study was to investigate the real-world performance of ILRs-including the time to diagnosis- in unselected patients with different ILR indications. METHODS AND RESULTS: In this multicenter, observational study, 871 patients with an indication of pre-syncope/syncope (61.9%), unexplained palpitations (10.4%), and atrial fibrillation (AF) detection with a history of cryptogenic stroke (CS) (27.7%) underwent ILR implantation. The median follow-up was 28.8 ± 12.9 months. In the presyncope/syncope group, 167 (31%) received a diagnosis established by the device. Kaplan-Meier estimates indicated that 16.9% of patients had a diagnosis at 6 months, and the proportion increased to 22.5% at 1 year. Of 91 patients with palpitations, 20 (22%) received a diagnosis based on the device. The diagnosis established at 12.2% of patients at 6 months, and the proportion increased to 13.3% at 1 year. Among 241 patients with CS, 47 (19.5%) were diagnosed with AF. The diagnostic yield of the device was 10.4% at 6 months and 12.4% at 1 year. In all cases, oral anticoagulation was initiated. Overall, ILR diagnosis altered the therapeutic strategy in 26.1% in presyncope/syncope group, 2.2% in palpitations group, and 3.7% in CS group in addition to oral anticoagulation initiation. CONCLUSIONS: In this real-world patient population, ILR determines diagnosis and initiates a new therapeutic management in nearly one fourth of patients. ILR implantation is valuable in the evaluation of patients with unexplained presyncope/syncope, CS and palpitations.

Long term effects of cardiac resynchronization therapy in non-ambulatory NYHA IV heart failure patients.

BACKGROUND: We aimed at evaluating the long-term effects of cardiac resynchronization therapy (CRT) in nonambulatory New York Heart Association (NYHA) IV heart failure patients (NAIVHFP). METHODS: Eighteen patients, 15 men and three women, eight with ischemic and 10 with nonischemic cardiomyopathy, who underwent biventricular pacemaker implantation while they were in nonambulatory NYHA IV class, were studied. Patients' age was 58 ± 9 years and left ventricular ejection fraction (LVEF) 18 ± 3%. Follow-up data were obtained through review of follow-up visits notes, stored echocardiographic studies, device interrogation data, and death certificates. RESULTS: After a mean duration of 1223 ± 846 days, 11 patients were alive, including five patients who underwent heart transplantation (OCT) and seven dead. Three of 11 patients who received a CRT-defibrillator, experienced at least one appropriate discharge, but eventually they either died or received an OCT during follow-up. Sustained improvements in NYHA class (Z = 2.4, P = 0.015) and 6-minute walk distance (0 vs 212 ± 95 m, P 0.001) were documented after a median duration of 855 days postimplantation. Cumulative proportion of death or OCT at 18 months-when full follow-up data were available-was 18%, which compared favorably with historical controls. Full echocardiographic and clinical follow-up data at 12-months postimplantation were available for 10 patients, documenting a significant reduction in end-systolic volume (248 ± 82 vs 269 ± 97 mL, P = 0.039). CONCLUSIONS: CRT can be safely applied in this subset of extreme severity heart failure patients, achieving encouraging survival rates and reverse remodeling effects. These observations can form an evidence-based rationale for including NAIVHFP in randomized CRT trials.

Inappropriate shocks from a transvenous implantable defibrillator caused by atrial fibrillation and a missed atrial septal defect in a patient with a modified Bentall procedure.

BACKGROUND: Inappropriate shocks have been reported in ∼1/3 of patients with implantable cardiac defibrillators (ICDs). We report an unusual case of inappropriate ICD shocks due to atrial fibrillation (AF) caused by a missed atrial septal defect (ASD) in a patient with a modified Bentall procedure. CASE SUMMARY: A 67-year-old Caucasian male, with an ICD and a history of a modified Bentall procedure 24 years ago, reported to our outpatient clinic with recurrent inappropriate ICD shocks due to episodes of fast AF. The transthoracic echocardiographic exam revealed two large aneurysms at the ostia of the coronary arteries. We performed further evaluation with transoesophageal echocardiogram and computed tomography (CT) angiography. The aneurysms measured on CT were 3.14 cm × 2.29 cm on the right ostium and 1.9 cm × 0.99 cm on the left. A large secundum type ASD of 1.5 cm, missed in all previous echocardiographic studies, was revealed. The therapeutic options of surgical closure of the ASD and repair of the aneurysms or a more conservative approach with percutaneous closure of the ASD and closer follow-up were discussed with the patient. The patient declined the surgical option due to high complication risk, and closure of the ASD with an Amplatzer device was performed 3 months later. A 3-year follow-up was uneventful. CONCLUSION: It is of major importance to comprehensively and thoroughly assess patients before and after a surgical intervention to not miss other treatable conditions preoperatively and complications in the postoperative period.

Disorders of the autonomic nervous system in patients with Brugada syndrome: a pilot study.

INTRODUCTION: The aim of this study was to examine autonomic disorders in patients with Brugada syndrome by performing a cardiac sympathetic innervation evaluation, a head-up tilt-test (HUT) and heart rate variability (HRV) analysis. METHODS AND RESULTS: We enrolled 20 patients with Brugada syndrome (mean age 42.5 +/- 8.8 years), 9 with spontaneous and 11 with an induced type 1 electrocardiogram (ECG) in the setting of symptoms and 20 age-matched controls. All subjects underwent a HUT with parallel measurements of plasma catecholamines and cortisol, a (123)I-metaiodobenzylguanidine single photon emission tomography, and HRV evaluation. Ten control subjects participated in the innervation portion of the study. The tilt-test with clomipramine challenge was positive in 15 of 20 (75%) patients (7 spontaneous, 8 induced) and in 1 in controls (P < 0.01). A sympathoadrenal imbalance was shown in positive tests. The pattern of innervation in all groups was heterogenic and similar to controls with a trend towards lower measurements in patients with a spontaneous type 1 ECG and a positive HUT. HRV analysis did not reveal any significant differences during day and night. Four patients (20%) had sustained ventricular arrhythmias during a follow-up of 31.1 +/- 8.6 months, but no correlations with innervation or response to tilting were found. CONCLUSION: A high susceptibility to vasovagal syncope was observed in patients with Brugada syndrome, which could be disease-related symptoms. Conversely, sympathetic innervation was observed to follow a physiological, heterogenic pattern; however, these factors did not have prognostic value for life-threatening arrhythmias.

Atrial fibrillation-related stroke in women: Evidence and inequalities in epidemiology, mechanisms, clinical presentation, and management.

BACKGROUND: Atrial fibrillation (AF) is the most common clinical arrhythmia and one of the major causes of stroke, heart failure, sudden death, and cardiovascular morbidity. Despite substantial advances in (interventional) rhythm control treatment during the last decade, anticoagulation for stroke prevention remains a major component of AF treatment. HYPOTHESIS: There are important sex-specific differences in AF-related stroke, resulting from sex-specific mechanisms and therapeutic differences. METHODS: This review summarizes available data on sex differences in risk assessment and prevention of stroke and highlights current knowledge gaps in AF-related stroke mechanisms, prevention and management that warrant further research. RESULTS: Increased thrombotic risk in women is multifactorial, involving hormonal changes after menopause, structural, endocrine and lifestyle/social factors and their interactions. It is clear from randomized studies that women benefit from anticoagulant treatment and that their bleeding risk is similar to men. Women should therefore receive equivalent treatment to men, based on the validated criteria for anticoagulation therapy. However, women are not represented equally in the large randomized studies and sex-related information in many fields is lacking. CONCLUSIONS: Female sex is an established risk factor for stroke in AF patients. The evidence for sex-specific differences in stroke risk assessment and stroke prevention is accumulating. However, the underlying biological mechanisms remain incompletely understood and further studies are required in order to decrease AF-related morbidity and mortality.

Minor psychiatric disorders and syncope: the role of psychopathology in the expression of vasovagal reflex.

BACKGROUND: A high prevalence of minor psychiatric disorders (MPDs) has been reported in patients with vasovagal syncope (VVS). However, the relationship between the psychiatric substrate and syncope remains unclear. METHODS: In order to test the hypothesis that MPDs may predispose to VVS, we assessed the prevalence of syncope, the response to head-up tilt test (HUTT) and the efficacy of psychiatric drug treatment in reducing syncopal episodes, in patients with recently diagnosed MPDs. The response to HUTT was compared with that in an equal number of matched (a) patients with VVS and (b) healthy controls. RESULTS: A high rate of patients with MPDs (58%) had a positive HUTT. Additionally, 45% had a history of syncope; among them, the rate of positive HUTT was identical to that in the VVS group (83%). Following psychiatric drug treatment, the number of patients with syncope decreased in the MPD group (6/67 from 30/67, p < 0.01). Psychiatric symptoms and quality of life were also improved. The number of syncopal spells decreased equally in the MPD and VVS groups (0.6 +/- 0.5 from 2.5 +/- 1.4, p < 0.01, and 0.7 +/- 0.5 from 2.7 +/- 1.3, p < 0.01, respectively). CONCLUSION: A high proportion of patients with MPDs experience syncope, associated with a high rate of positive HUTT, comparable to that observed in VVS. Psychiatric treatment results in the improvement of syncopal and psychiatric symptoms. These findings suggest involvement of co-occurring MPDs in the pathogenesis of VVS. Therefore, the diagnosis and treatment of MPDs, when present, may be crucial for the effective therapy of vasovagal syndrome.

Conduction abnormalities after transcatheter aortic valve implantation.

In the last few years, transcatheter aortic valve implantation (TAVI) has become an alternative procedure in patients with severe aortic stenosis and high risk for surgical aortic replacement. Due to the anatomic correlation between aortic valve structure and conduction system of the heart, one of the most common complications after TAVI is conduction system disturbances which including bundle branch block, complete heart block and need for permanent pacemaker implantation. Although these disturbances are usually not lethal, they may have a great influence on patients' state and long term-survival. Several risk factors for conduction disturbances have been identified which including age, anatomy of the heart, periprocedural factors, type of implanted valve, preexisting abnormalities and comorbidities. As this technique becomes more familiar to physicians, patients should be carefully screened for risk factors for the development of conduction abnormalities after TAVI in order to provide effective prevention and proper treatment.

Neurocardiogenic mechanisms of unexplained syncope in idiopathic dilated cardiomyopathy.

Syncope in patients with advanced heart failure is a sign of poor prognosis. The cause of syncope in patients with dilated cardiomyopathy (DC) is not fully recognized and may remain elusive even after standardized evaluation. The purpose of the present study was to examine the implication of neurally mediated mechanisms in the pathophysiology of syncopal episodes in patients with DC. Twenty-six patients (21 men, 5 women; mean age 59 +/- 2 years, range 38 to 79) with DC and left ventricular ejection fractions

NT-proBNP levels and diastolic dysfunction in beta-thalassaemia major patients.

BACKGROUND: The early diagnosis and treatment of heart failure in beta-thalassaemic patients is related to survival. Iron alone or in combination with other factors causes diastolic dysfunction, which usually precedes systolic dysfunction. NT-proBNP is a sensitive biomarker of ventricular dysfunction. AIM: To evaluate NT-proBNP in non heart failure beta-thalassaemic patients. METHODS: Fifty-two beta-thalassaemia major patients (mean age: 27.2+/-12.5 years) with normal LV systolic function, underwent NT-proBNP measurement and a thorough Doppler-echocardiographic and pulsed tissue-Doppler study, 4 days following blood transfusion. Fifty-two age matched healthy controls were also studied. RESULTS: NT-proBNP and E/E' ratio were increased in thalassaemic patients compared with controls [(469+/-171 vs 262+/-51 pmol/l, p<0.001) and (10.8+/-4.0 vs 6.6+/-1.1, p<0.001)] and were well correlated (r: 0.54, p<0.01). Although NT-proBNP levels were increased in patients with higher E/E' ratios (E/E' <8: 354+/-119, 8-15: 516+/-177, >15: 565+/-114 pmol/l, ANOVA p: 0.002) this increase only became statistically significant in the 3rd decade of life, while E/E' ratio increased in the 4th decade. CONCLUSION: NT-proBNP increases in beta-thalassaemia major patients and is related to age and LV diastolic dysfunction. NT-proBNP appears to be an early biomarker of LV diastolic dysfunction, compared with the conventional Echo-Doppler indexes.

Hydroquinidine Prevents Life-Threatening Arrhythmic Events in Patients With Short QT Syndrome.

BACKGROUND: Short QT syndrome (SQTS) is a rare and life-threatening arrhythmogenic syndrome characterized by abbreviated repolarization. Hydroquinidine (HQ) prolongs the QT interval in SQTS patients, although whether it reduces cardiac events is currently unknown. OBJECTIVES: This study investigated whether long-term treatment with HQ reduces the occurrence of life-threatening arrhythmic events (LAE) (cardiac arrest or sudden cardiac death) in SQTS patients. METHODS: In this cohort study on consecutive SQTS patients, 2 analyses were performed: 1) a matched-period analysis for the occurrence of LAE in 17 SQTS patients who received long-term HQ; and 2) a comparison of the annual incidence of LAE off- and on-HQ in 16 SQTS patients who survived a cardiac arrest. RESULTS: A total of 17 patients (82% male, age 29 ± 3 years, QTc before treatment 331 ± 3 ms) received HQ therapy (584 ± 53 mg/day). Therapy was stopped in 2 cases (12%) due to gastrointestinal intolerance, and 15 patients continued treatment for 6 ± 1 year. QTc prolongation was observed in all patients (by 60 ± 6 ms; p < 0.001). We compared the occurrence of LAE during 6 ± 1 years before and after HQ, observing that patients on HQ experienced a reduction in both the rate of LAE from 40% to 0% (p = 0.03) and the number of LAE per patient from 0.73 ± 0.3 to 0 (p = 0.026). Furthermore, the annual rate of LAE in the 16 patients with a previous cardiac arrest dropped from 12% before HQ to 0 on therapy (p = 0.028). CONCLUSIONS: We demonstrated for the first time that treatment with HQ was associated with a lower incidence of LAE in SQTS patients. These data point to the importance that quinidine, that in several countries has been removed from the market, remains available worldwide for patients with SQTS. In the present study, therapy with HQ has been proven to be safe, with a relatively low rate of side effects.

Management of Coronary Artery Disease and Conduction Abnormalities in Transcatheter Aortic Valve Implantation.

OPINION STATEMENT: Transcatheter aortic valve replacement (TAVR) is an expanding, catheter-based technology that allows the implantation of a prosthetic valve without requiring open heart surgery for the treatment of severe aortic stenosis (AS). The frequency of coronary artery disease (CAD) in patients (pts) with severe AS undergoing surgical treatment ranges from 30 to 50 %. This tends to be higher in pts undergoing TAVR with a prevalence of 49-76 % and is more prevalent with older age and the fact that TAVR is commonly performed in high-risk groups with more advanced cardiovascular disease. The overall influence of CAD on TAVR procedural outcomes remains controversial, and the management of concomitant artery disease is still under discussion. There are three major issues that must be addressed: the impact of CAD, optimal timing of percutaneous coronary intervention (PCI) and TAVR, and extent of revascularization. Today, TAVR is commonly performed as a stand-alone procedure with variable degrees of concomitant CAD tolerated without intervention. One of the major potential complications with TAVR is the damage to the conduction system. The requirement of permanent pacemaker (PM) implantation ranges from 9 to 49 % of cases with a mean of ~20 %, whereas surgical aortic valve replacement (sAVR) is associated with a complete heart block that requires permanent PM in 3-12 % of cases. Reports have demonstrated an increased incidence of conduction damage in patients undergoing TAVR with the CoreValve (Medtronic Minneapolis, MN, USA) prosthesis (mean 20.8 %, range 9.3-30.0 %) compared with the Edwards SAPIEN (Edwards Lifesciences LLC; Irvine, CA, USA) prosthesis (mean 5.4 %, range 0-10.1 %). Factors predicting PM implantation include preexisting bundle branch block (BB) or conduction abnormalities. The prognostic significance of new left bundle branch block (LBBB) after TAVR is unclear. In the future, new valve designs may improve the incidence of permanent PM implantation after TAVR.

Safety and efficacy of novel oral anticoagulants: a comparison to vitamin K antagonists.

Novel oral anticoagulants (NOACs) have been developed as alternatives for vitamin K antagonists (VKAs) for the prevention of thromboembolic events in patients with a variety of medical conditions. In this review, we summarize the current data on NOACs safety and efficacy compared to VKAs and in specific patients' groups including heart valve replacement, venous thromboembolism, advanced renal failure and the elderly.

Left ventricular pseudoaneurysm formation: Two cases and review of the literature.

Left ventricular wall rupture (LVWR) comprises a complication of acute myocardial infarction (AMI). Acute LVWR is a fatal condition, unless the formation of a pseudoaneurysm occurs. Several risk factors have been described, predisposing to LVWR. High index of suspicion and imaging techniques, namely echocardiography and computed tomography, are the cornerstones of timely diagnosis of the condition. As LVWR usually leads to death, emergency surgery is the treatment of choice, resulting in significant reduction in mortality and providing favorable short-term outcomes and adequate prognosis during late follow-up. Herein, we present two patients who were diagnosed with LVWR following AMI, and subsequent pseudoaneurysm formation. In parallel, we review the aforementioned condition.

A case-matched comparative study of surgical radiofrequency (RF) ablation for patients with persistent or long-standing atrial fibrillation undergoing concomitant heart surgery.

INTRODUCTION: Recent guidelines from the European Society of Cardiology suggest that surgical ablation should be considered in patients with atrial fibrillation (AF) who present for concomitant surgically correctable disease. This is a case-matched study of radiofrequency ablation during concomitant cardiac surgery versus lone surgery on patients with persistent and long-standing permanent AF. METHODS: Surgical ablation was performed in 21 patients, 14 with persistent and 7 with long-standing permanent AF. Patients with paroxysmal AF, recent onset persistent AF (<6 months), duration >6 years or left atrial diameter >8 cm were excluded. The study patients were matched 1-2 for age, sex, type of operation, type and duration of atrial fibrillation with 42 patients operated during the same period in the same department without ablation. The catheters used deliver continuously monitored radiofrequency energy, creating linear lesions on the inside of the arrested left and/or right atrial wall. Follow up was with regular outpatients' appointments and 24-hour ECG recordings at 6 and 12 months. RESULTS: Sinus rhythm maintenance rate at discharge and 12-month follow up was significantly higher in the ablation group (12 months: 71% vs. 5%, p<0.01). The ablation group had significantly longer operative times. Mean ablation duration was 15.5 minutes (CI: 12-20). There were no deaths. There were no statistically significant differences in postoperative in-hospital stay, NYHA class, left atrial size, or left ventricular ejection fraction. All patients who maintained sinus rhythm during the ablation had echocardiographically confirmed left atrial systole at follow up. CONCLUSION: Epicardial radiofrequency ablation in patients with persistent and long lasting permanent AF, who are being operated for concomitant cardiac surgical disease, is a safe, reproducible method with acceptable sustainability of sinus rhythm at medium-term follow up.

Dislocation of an infected and abandoned pacemaker lead.

We present a case of pacemaker lead dislodgment in an 83-year-old patient with a pacemaker infection. Initially, the generator and the proximal part of the leads were removed, and the remaining leads were severed and abandoned. Twenty-five days later, dislodgment of both abandoned leads and systemic infection were documented. The leads were then surgically removed without further complications.

Patents in the diagnosis and therapy of neurocardiogenic syncope.

Neurocardiogenic syncope is one of the most common types of syncope, characterized by arterial vasodilatation with or without bradycardia. The regulation of blood pressure and heart rate is the result of a complex reaction between the central and peripheral nervous system with the circulatory system. Multiple therapies, pharmaceutical and interventional, have been applied without any proven effect. The initial positive reports on pacing were not demonstrated in enough number of controlled studies. Neurocardiogenic syncope continues to remain a clinical problem in terms of understanding its underlying mechanisms and therapy needs to be enlightened by future studies. This article provides a background of diagnosis and therapy of neurocardiogenic syncope and reviews some related patents.