Cardiometabolic risk factors and antithrombotic treatment in a Mexican population with atrial fibrillation and heart failure with reduced ejection fraction.

Introduction: Heart failure in patients with non-valvular atrial fibrillation (NVAF) is two to three times more common than in individuals without NVAF.

Objective: To identify cardiometabolic risk factors (CMRF) and antithrombotic treatment in patients with NVAF and heart failure with reduced ejection fraction (HFrEF), and to determine if there were differences according to gender.

Methods: CMRF, pro-thrombotic risk, bleeding risk, and antithrombotic therapy were globally analyzed and according to gender.

Worldwide Survey of COVID-19-Associated Arrhythmias.

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Anticoagulation Therapy by Age and Embolic Risk for Nonvalvular Atrial Fibrillation in Mexico, an Upper-Middle-Income Country: The CARMEN-AF Registry.

Background: Documenting the patterns of oral anticoagulation therapy (OAT) is essential to prevent thromboembolic complications of nonvalvular atrial fibrillation (NVAF).

Objective: To report the patterns of OAT according to age and thromboembolic risk in patients included in CARMEN-AF, a nationwide registry of NVAF in Mexico, an upper middle-income country.

Material And Methods: There were 1,423 consecutive patients ≥18 years old and with at least one thromboembolic risk factor enrolled in the CARMEN-AF Registry at their regular clinical visit during a three-year period.

Grapefruit juice prolongs the QT interval of healthy volunteers and patients with long QT syndrome.

Background: The list of medications linked to drug-induced long QT syndrome (LQTS) is diverse. It is possible that food products too have QT-prolonging potential.

Objective: We tested the effects of grapefruit juice on the QT interval with the methodology used by the pharmaceutical industry to test new drugs.

Gender differences and management of stroke risk of nonvalvular atrial fibrillation in an upper middle-income country: Insights from the CARMEN-AF registry.

Background: Atrial Fibrillation (AF) is associated with an increased risk of stroke and systemic embolism. Several studies have suggested that female AF patients could have a greater risk for stroke. There is scarce information about clinical characteristics and use of antithrombotic therapies in Latin American patients with nonvalvular AF.

Female gender as independent risk factor of torsades de pointes during acquired atrioventricular block.

Background: Female gender increases the risk of torsades de pointes (TdP) in the long QT syndrome, and this increased risk is assumed to be due to their longer QT interval.

Objective: The purpose of this study was to study the interplay between gender, duration of the QT interval, and risk of TdP during AV block.

Methods: We studied 250 patients (48% women) with AV block.

[Prevalence and implicated risk factors associated with the exteriorization of cardiac pacemakers: 5 year follow-up].

Background: Infection is the most common complication related to permanent pacemaker implantation. The objetive of this study is to establish the prevalence and determine the frequency of risk factors associated with exteriorization of cardiac pacemakers at the Department of Cardiac Electrophysiology at the UMAE Hospital de Especialidades "Dr. Antonio Fraga Mouret" Centro Médico Nacional La Raza, Instituto Mexicano del Seguro Social.

Long QT syndrome complicating atrioventricular block: arrhythmogenic effects of cardiac memory.

Background: The magnitude of QT prolongation in response to bradycardia, rather than the bradycardia per se, determines the risk for torsade de pointes during atrioventricular block (AVB). However, we do not know why some patients develop more QT prolongation than others, despite similar bradycardia. We hypothesized that in patients who develop significant QRS vector changes during AVB, the effects of cardiac memory lead to excessive QT prolongation.

Quinidine, a life-saving medication for Brugada syndrome, is inaccessible in many countries.

Objectives: The aim of this study was to determine the availability of quinidine throughout the world.

Background: Quinidine is the only oral medication that is effective for preventing life-threatening ventricular arrhythmias due to Brugada syndrome and idiopathic ventricular fibrillation. However, because of its low price and restricted indication, this medication is not marketed in many countries.

[Cardiac pacemaker dysfunction due to rotation of the battery (reel syndrome)].

Reel syndrome is characterized by the rotation of permanent pacemaker generator on its transverse axis and electrode catheters curl around it, so this causes displacement of the electrodes with the loss of atrial and ventricular pacing. It can cause severe symptoms due to dysfunction of the pacemaker. We present three patient cases who after the placement of pacemaker attended by dysfunction of the displacement of the electrodes their clinical pictures were compatible with Reel syndrome.

The phenomenon of "QT stunning": the abnormal QT prolongation provoked by standing persists even as the heart rate returns to normal in patients with long QT syndrome.

Background: Patients with long QT syndrome (LQTS) have inadequate shortening of the QT interval in response to the sudden heart rate accelerations provoked by standing-a phenomenon of diagnostic value. We now validate our original observations in a cohort twice as large. We also describe that this abnormal QT-interval response persists as the heart rate acceleration returns to baseline.

[Remote monitoring and follow up of implantable cardioverter defibrillators and cardiac resynchronization therapy devices].

Introduction: The implantable cardiac devices like regular pacemaker, cardiac resynchronization therapy (CRT) automatic implantable defibrillators (ICD) and CRT associate with ICD (CRTD) are now being used frequently. Patient visits to pacemaker and ICD clinics for review and monitoring, has increases significantly. We present the experience of monitoring via satellite of patients with implantable cardiac devices in Mexico.

[New antiarrthythmics in atrial fibrillation].

Atrial fibrillation is the most common cardiac arrhythmia responsible for a significant morbidity and mortality. In recent years, progress has been made in determining the genetic abnormalities, the use of anticoagulants as a component of a primary treatment strategy in many patients who have a high risk of recurrence and for thromboembolism, and newer and safer antiarrthythmics are now available. The aim of this paper is to discuss about this topic and antiarrhythmic therapy.

[Clinical benefit in cardiac resynchronization].

Despite the improvement in pharmacologic treatment of heart failure, many patients continue to have severe persistent symptoms, and their prognosis remains poor. One of the most recent advances in heart failure management is the concept of cardiac resynchronization therapy (CRT). Large clinical trials have demonstrated morbidity and mortality benefits of CRT in patients with moderate to severe drug refractory heart failure (New York Heart Association [NYHA] functional class III or IV), and ejection fraction < or = 35% with QRS duration > or = 120 ms.

The response of the QT interval to the brief tachycardia provoked by standing: a bedside test for diagnosing long QT syndrome.

Objectives: This study was undertaken to determine whether the short-lived sinus tachycardia that occurs during standing will expose changes in the QT interval that are of diagnostic value.

Background: The QT interval shortens during heart rate acceleration, but this response is not instantaneous. We tested whether the transient, sudden sinus tachycardia that occurs during standing would expose abnormal QT interval prolongation in patients with long QT syndrome (LQTS).

[Remote monitoring of automatic implantable cardiovascular devices (pacemakers, implantable cardioverter defibrillator and cardiac resynchronization)].

In the era of communication technology, new options are available to monitor patients with Automatic Implantable Cardiovascular Devices (AICD) implanted pacemaker (PM) and Automatic Implantable Defibrillators (AID) and Cardiac resynchronization system (CRS). Most companies offer devices with wireless capabilities to communicate automatically with transmitters, allowing remote monitoring device. These systems are being widely used in USA for remote monitoring and have been introduced more recently in Europe, where adoption is increasing.

[Infrequent electrocardiographic changes during exercise stress test in a patient with Brugada's syndrome].

38 year old patient with a syncope history and family background of sudden death had an electrocardiogram compatible with the "Brugada Syndrome". When an exercise stress testing with Bruce protocol was done, we found that during the effort phase and at maximum effort, contrary to a ST segment normalization, a discreet increase of the ST segment elevation of 2 mm in V1 and V2 occurred. During recovery phase a decrease in the ST segment elevation was observed, at a normal level as before the test.

[Trans-septal puncture for radiofrequency ablation of left accessory pathway].

We present the case of an 18-year-old male patient with diagnosis of Wolff Parkinson-White syndrome due to a left free wall accessory pathway. We performed an electrophysiology study and transseptal punction guided by transesophageal echocardiogram to via access to the left atrium. We performed successful radiofrequency ablation of the accessory pathway, observing disappearance of the delta wave on the first attempt.

[Ventricular resynchronization in the treatment of heart failure].

Despite the major advances in medical drug therapy, heart failure remains a syndrome with high mortality and morbidity. Biventricular pacing is being tested in congestive heart failure patients with left bundle branch block of an advanced degree. The aim is to resynchronize the dyscoordinate left ventricle contraction.

[Atrioventricular nodal reentrant tachycardia: Radiofrequency ablation].

Atrioventricular nodal reentrant tachycardia is the most frequent regular supraventricular tachycardia. It is generally a benign arrhythmia and usually it is no associated with heart disease. It is more often seen in middle-aged women but it is no infrequent in younger and older patients.

[ Segmental ostial ablation to interrupt electrical conduction in a single pulmonary vein for the prevention of idiopathic paroxysmal atrial fibrillation].

Several studies have shown the role of focal trigers in the pulmonary veins initiating episodes of atrial fibrillation. Radiofrequency catheter ablation of this foci is a curative therapy for paroxysmal atrial fibrillation. We report a case of idiopathic paroxysmal atrial fibrillation triggered by abnormal electrical activity in a single pulmonary vein.

Radiofrequency ablation of atrioventricular accessory pathways associated with discordant atrioventricular connections.

Discordant atrioventricular connections associated with Wolff-Parkinson-White syndrome increase the challenge of radiofrequency ablation. We report the results and techniques of radiofrequency ablation in three patients with discordant atrioventricular connections, including one patient having double outlet right ventricle with atrioventricular reentry tachycardias. There were two males and one female, aged 14 and 22 years old.