Progressive conduction disturbance in myotonic dystrophy

Myotonic dystrophy (DM), the commonest dystrophy in adults, is an autosomal dominant disease characterized by a variety of multisystemic features. Two main genetically distinct forms of DM have been identified: type 1 (DM1), the classic form first described by Steinert, and type 2 (DM2), identified by Ricker. DM1 is caused by trinucleotide expansion of cytosine- -thymine-guanine (CTG) in the myotonic dystrophy protein kinase gene, whereas in DM2 the expansion of tetranucleotide repeats (CCTG) in the zinc finger protein 9 gene was identified. Both mutations are dynamic and are located in non-coding parts of the genes. Phenotype variability of DM1 and DM2 is caused by a molecular mechanism due to mutated RNA toxicity. DM1 is characterized by myotonia and multi-organ damage with major cardiac involvement. The disease is usually slowly progressive and life expectancy is reduced by the increased mortality associated with cardiopulmonary complications. Sudden death can occur as a consequence of cardiac-conduction abnormalities. We present the ECG of a 26 year-old male with DM1 and progressive conduction system disturbance characterized by syncopal episodes. (Cardiol J 2011; 18, 3: 322–325

Pericarditis constrictiva

Fil: Trucco, Emilce. Hospital Español de Mendoza. Departamento de Cardiología.Fil: Bernasconi, Pablo. Hospital Español de Mendoza. Departamento de Cardiología.Fil: Tirado, Gabriel. Hospital Español de Mendoza. Departamento de Cardiología.Fil: Astesiano, Alfredo. Hospital Español de Mendoza. Departamento de Cardiología

Failure-free survival of the Riata implantable cardioverter-defibrillator lead after a very long-term follow-up

Aims: Riata® implantable cardioverter-defibrillator (ICD) leads from St. Jude Medical are prone to malfunction. This study aimed to describe the rate of this lead's malfunction in a very long-term follow-up. Methods: This single-centre observational study included 50 patients who received a Riata 7Fr dual-coil lead between 2003 and 2008. Follow-up was conducted both in person and remotely, and analysed at 8-month intervals. We evaluated the rates of cable externalization (CE), electrical failure (EF), and the interaction of these two complications. Structural lead failure was defined as radiographic CE. Oversensing of non-cardiac signal or sudden changes in impedance, sensing, or pacing thresholds constituted EF. Results: During a mean follow-up of 10.2 ± 2.9 years, 16 patients (32%) died. We observed lead malfunction in 13 patients (26%): three (23%) due to CE, six (46%) to EF and four (31%) to both complications. Of the malfunctioning leads, 77% failed after seven years of follow-up. The incidence rate (IR) of overall malfunction per 100 patients per year was 0.9 during the first seven years post-implantation, increased to 7.0 after the 7th year and more than doubled (to 16.7) after 10 years. Beyond seven years post-implantation, IR per 100 patient-years increased in both EF and CE (from 0.6 to 5.6 vs. 0.3 to 4.2, respectively). Presence of CE was associated with a 4-fold increase in the proportion of EF. Conclusion: The incidence of Riata ICD lead malfunction, both for EF and CE, increased dramatically after seven years and then more than doubled after 10 years post-implantation

Repeat cryoablation as a redo procedure for atrial fibrillation ablation: Is it a good choice?

Background: Ablation of atrial fibrillation (AF), both cryoablation ablation (CBA) and radiofrequency catheter ablation (RFCA), have demonstrated to be safe and effective. About 1 in 3 patients may face a redo due to recurrence and the best technique is unknown. The aim of this study is to assess the efficacy of CBA as a repeat procedure in patients with prior CBA or RFCA. Methods: A nation-wide CBA registry (RECABA) was analyzed and patients were compared who had previously undergone CBA (Prior-CB) or RFCA (Prior-RF). The primary endpoint was AF recurrence at 12 months after a 3-month blanking period. A survival analysis was performed, univariate and multivariate Cox models were also built. Results: Seventy-four patients were included. Thirty-three (44.6%) were in the Prior-CB group and 41 (55.4%) in the Prior-RF. There were more reconnected pulmonary veins in the Prior-RF than in Prior-CB group (40.4% vs.16.5%, p = 0.0001). The 12-month Kaplan–Meier estimate of freedom from AF recurrence after the blanking period was 61.0% (95% confidence interval [CI] 41.4–75.8%) in the Prior-CB, and 89.2% (95% CI 73.6–95.9%) in the Prior-RF group (p = 0.002).  Multivariate Cox regression pointed Prior-CB as the sole independent predictor of AF recurrence, with an adjusted HR of 2.67 (95% CI 1.05–6.79). Conclusions: Repeat CBA shows higher rates of AF recurrences compared to CBA after a previous RFCA despite presenting less reconnected veins at the procedure. These data suggest that patients with AF recurrence after CBA may benefit from other ablation techniques after a recurrence. RECABA is registered at clinicaltrials.gov with the Unique Identifier NCT02785991

Inappropriate ICD Shocks - When Monitoring Zones Do More Than Monitor

The ventricular tachycardia (VT) monitoring zone in implantable cardioverter defibrillators (ICDs) is usually programmed to detect slow VTs. However, it is not well known whether programming this zone can affect the ICD arrhythmia redetection or confirmation criteria. We report two cases of inappropriate ICD shocks due to the programming of a slow VT monitoring zone in the same device model

Multimodality Imaging in the Study of the Left Atrium

The left atrium (LA) plays a vital role in maintaining normal cardiac function. Many cardiac diseases involve the functioning of the LA directly or indirectly. For this reason, the study of the LA has become a priority for today’s imaging techniques. Assessment of LA size, function and wall characteristics is routinely performed in cardiac imaging laboratories when a patient undergoes transthoracic echocardiography. However, in cases when the LA is the focus of disease management, such as in atrial fibrillation or left atrial appendage closure, the use of multimodality is critical. Knowledge of the usefulness of each cardiac imaging technique for the study of LA in these patients is crucial in order to choose the most appropriate treatment. While echocardiography is the most widely performed technique for its evaluation and the study of wall deformation analysis is increasingly becoming more reliable, multidetector computed tomography allows a detailed analysis of its anatomy to be carried out in 3D reconstructions that help in the approach to interventional treatments. In addition, the evaluation of the wall by cardiac magnetic resonance imaging or the generation of electroanatomical maps in the electrophysiology room have become essential tools in the treatment of multiple atrial pathologies. For this reason, the goal of this review article is to describe the basic anatomical and functional information of the LA as well as their study employing the main imaging techniques currently available, so that practitioners specializing in cardiac imaging techniques can use these tools in an accurate and clinically useful manner

¿Es necesaria la prueba de inclinación en pacientes con diagnóstico clínico de síncope vasovagal?: Resultados utilizando un protocolo no sensibilizado

Introducción:La prueba de inclinación es un estudio no invasivo, sencillo y de bajo riesgo, donde la utilización de protocolos no sensibilizados sirven para acortar los tiempos de la prueba. Objetivo:Determinar en pacientes con síncope la utilidad de la prueba de inclinación no sensibilizada con fármacos y comparar los resultados con la probabilidad clínica pre-test. Métodos:Se incluyeron pacientes >15 años de edad, con síncope o presíncope, con clínica sugestiva de origen vasovagal, utilizando la escala de Calgary. Resultados:Se analizaron 70 pacientes; edad: 39 ± 20 años, 66% mujeres. De los pacientes, 94% presentó una puntuación >-1, pero sólo 30% de las pruebas fueron positivas. Una puntuación >-2 no se asoció con el resultado de la prueba. La mayoría de los pacientes presentaron una puntuación de 1 (52) y 2 (11), resultando en una prueba positiva en 32% y 9%, respectivamente. En pacientes con probabilidad pre-test baja, hubo mayor número de pruebas negativas (100% con una puntuación de -2 y 50% con puntuación de -5). Conclusiones:El estudio mostró que en pacientes con síncope vasovagal, sugerido por la evaluación clínica, la prueba de inclinación no sensibilizada no proporcionó información adicional, con un número significativo de falsos negativos

In‐vivo compatibility between pacemakers and dental equipment

In‐vitro studies suggest that electromagnetic interference can occur under specific conditions involving proximity between electronic dental equipment and pacemakers. At present, in‐vivo investigations to verify the effect of using electronic dental equipment in clinical conditions on patients with pacemakers are scarce. This study aimed to evaluate, in vivo, the effect of three commonly used electronic dental instruments – ultrasonic dental scaler, electric pulp tester, and electronic apex locator – on patients with different pacemaker brands and configurations. Sixty‐six consecutive non‐pacemaker‐dependent patients were enrolled during regular electrophysiology follow‐up visits. Electronic dental tools were operated while the pacemaker was interrogated, and the intracardiac electrogram and electrocardiogram were recorded. No interferences were detected in the intracardiac electrogram of any patient during the tests with dental equipment. No abnormalities in pacemaker pacing and sensing function were observed, and no differences were found with respect to the variables, pacemaker brands, pacemaker configuration, or mode of application of the dental equipment. Electromagnetic interferences affecting the surface electrocardiogram, but not the intracardiac electrogram, were found in 25 (37.9%) patients, especially while using the ultrasonic dental scaler; the intrinsic function of the pacemakers was not affected. Under real clinical conditions, none of the electronic dental instruments tested interfered with pacemaker function.Peer reviewe