Spectral Analysis and Mutual Information Estimation of Left and Right Intracardiac Electrograms during Ventricular Fibrillation.

Ventricular fibrillation (VF) signals are characterized by highly volatile and erratic electrical impulses, the analysis of which is difficult given the complex behavior of the heart rhythms in the left (LV) and right ventricles (RV), as sometimes shown in intracardiac recorded Electrograms (EGM). However, there are few studies that analyze VF in humans according to the simultaneous behavior of heart signals in the two ventricles. The objective of this work was to perform a spectral and a non-linear analysis of the recordings of 22 patients with Congestive Heart Failure (CHF) and clinical indication for a cardiac resynchronization device, simultaneously obtained in LV and RV during induced VF in patients with a Biventricular Implantable Cardioverter Defibrillator (BICD) Contak Renewal IVTM (Boston Sci.). The Fourier Transform was used to identify the spectral content of the first six seconds of signals recorded in the RV and LV simultaneously. In addition, measurements that were based on Information Theory were scrutinized, including Entropy and Mutual Information. The results showed that in most patients the spectral envelopes of the EGM sources of RV and LV were complex, different, and with several frequency peaks. In addition, the Dominant Frequency (DF) in the LV was higher than in the RV, while the Organization Index (OI) had the opposite trend. The entropy measurements were more regular in the RV than in the LV, thus supporting the spectral findings. We can conclude that basic stochastic processing techniques should be scrutinized with caution and from basic to elaborated techniques, but they can provide us with useful information on the biosignals from both ventricles during VF.

Reel Versus Twiddler Syndrome in a Patient With a Pacemaker: A Case Report of Iatrogenic Manipulation.

Twiddler syndrome is a rare entity in which patient manipulation causes lead dislocation with lead retraction. Reel syndrome, on the other hand, is observed after external manipulation, intentional or unintentional, in which the leads move along their transverse axis and is considered a variant of Twiddler syndrome. We present the clinical case of a 91-year-old female who, after pacemaker implantation, presented with dizziness and chest discomfort following constant manipulation of the pacemaker, resulting in complete retraction of the lead tip into the pouch, which is unusual in the literature to date.

Arrhythmogenic Cardiomyopathy and Athletes: A Dangerous Relationship.

Arrhythmogenic cardiomyopathy (ACM) is a disease characterized by a progressive replacement of myocardium by fibro-adipose material, predisposing to ventricular arrhythmias (VA) and sudden cardiac death (SCD). Its prevalence is estimated at 1:2000 to 1:5000, with a higher incidence in males, and clinical onset is usually between the 2nd and 4th decade of life. The prevalence of ACM in SCD victims is relatively high, making it one of the most common etiologies in young patients with SCD, especially if they are athletes. Cardiac events occur more frequently in individuals with ACM who participate in competitive sports and/or high-intensity training. In effect, exercise activity can worsen RV function in cases of hereditary ACM. Estimating the incidence of SCD caused by ACM in athletes remains challenging, being reported frequency ranging from 3% to 20%. Here, we review the potential implications of exercising on the clinical course of the classical genetic form of ACM, as well as the diagnostic tools, risk stratification, and the different therapeutic tools available for managing ACM.

Multicenter prospective comparison of conventional and high-power short duration radiofrequency application for pulmonary vein isolation: the high-power short-duration radiofrequency application for faster and safer pulmonary vein ablation (POWER FAST III) trial.

BACKGROUND: Electrical isolation of pulmonary veins (PV) with high-power short-duration (HPSD) radiofrequency application (RFa) may reduce the duration of atrial fibrillation (AF) ablation, without compromising the procedural efficacy and safety in comparison with the conventional approach. This hypothesis has been generated in several observational studies; the POWER FAST III will test it in a randomized multicenter clinical trial. METHODS: It is a multicenter randomized, open-label and non-inferiority clinical trial with two parallel groups. AF ablation using 70 W and 9-10 s RFa is compared with the conventional technique using 25-40 W RFa guided by numerical lesion indexes. The main efficacy objective is the incidence of atrial arrhythmia recurrences electrocardiographically documented during 1-year follow-up. The main safety objective is the incidence of endoscopically detected esophageal thermal lesions (EDEL). This trial includes a substudy of incidence of asymptomatic cerebral lesions detected by magnetic resonance imaging (MRI) after ablation. RESULTS: A randomized clinical trial compares for the first time high-power short-duration and conventional ablation in order to obtain data about the efficacy and safety of the high-power technique in an adequate methodological context. CONCLUSIONS: The results of the POWER FAST III could support the use of the high-power short-duration ablation in clinical practice. REGISTRATION: ClinicalTrials.gov: NTC04153747.

Association of carbohydrate 125 antigen with sepsis mortality in critical patients. / Asociación del antígeno carbohidrato 125 con la mortalidad por sepsis en pacientes críticos.

INTRODUCTION: The increased synthesis of CA125 in mesothelial cells is connected with pathophysiological processes, also present in sepsis, that link inflammation with systemic congestion. We propose to evaluate serum levels of this biomarker in patients with sepsis and to study its association with the severity and evolution of the disease. METHODS: Longitudinal retrospective observational study, which included 126 patients admitted to an Intensive Care Unit with sepsis criteria. The main variables analyzed were: CA125 values for 7 days, the variation of its levels according to the source of infection (abdominal, pulmonary, nephrourinary and others), sepsis, septic shock, APACHE-II score and mortality. RESULTS: CA125 levels remained elevated throughout the study period. The abdominal focus presented higher mean levels of CA125 (62±55.5U/mL; P=.001) and were higher in non-survivors (77.2U/mL; interquartile range 35.9-118.5; P=.0273). CA125 levels>35U/mL throughout the weal had an independently effect on the evolution (relative risk [RR] 3.1; 95% confidence interval [CI] 1.6-6.2; P=.001) and the elevated mean value of CA125 was also associated with mortality (RR 1.004; 95% CI 1.001-1.005; P=.0001). CONCLUSIONS: Septic patients presented high levels of CA125 on the study days, being higher in abdominal infections. In our study, serial determination of CA125 is a prognostic marker of mortality independent of age, origin of infection or severity.

Diagnostic electrophysiological study in a highly trained young woman with presyncopal symptoms during exercise: a case report.

Right ventricular outflow tract (RVOT) ventricular tachycardia (VT) is frequent and occurs in patients without structural heart disease, especially in highly trained athletes. Most of the studies on cardiac adaptations to exercise have been investigated in male athletes. Women, however, are increasingly participating in sports and electrical and structural adaptations in male and female athletes differ significantly. These cardiac adaptations dissimilarities between males and females have potential implications in diagnosing certain types of arrhythmias. We present here a case of a 35-year-old highly-trained woman endurance athlete that attended the clinic complaining about chest pain and dyspnea on exertion, dizziness and presyncope occurring during maximum-intensity exercise training sessions. An exercise stress testing was performed on cycle ergometer. The test elapsed normally until the patient reached a heart rate of 169 bpm, when she presented identical symptoms to those described during the first interview in the clinic. A wide-complex and notched QRS tachycardia was observed in the inferior leads, inferior axis leads and transition from leads V4 to V5, suspending the test immediately. The patient was referred to perform an electrophysiological study and eventually radiofrequency catheter ablation in order to eliminate the culprit VT. Precocity occurred in the posterior lateral wall of the RVOT, immediately below the pulmonary valve. Radiofrequency application in the arrhythmogenic focus suppressed all ectopic activity despite maintaining isoproterenol infusion. After 30 minutes, the effect was maintained, and the ectopic focus was successfully ablated. The recognition of this clinical entity in females may be challenging since cardiac remodeling in response to exercise may be invaluable due to their biological, anatomical, and hormonal characteristics. In effect, electrical and structural adaptations in males and females may differ considerably. Both exercise stress testing and diagnostic electrophysiological study represent essential and invaluable tools to reach a final diagnosis, especially in highly trained females.

Cardiac magnetic resonance in the diagnosis of the unusually detected acute myocarditis in the young people: a case report.

Myocarditis is among the causes of arrhythmic sudden cardiac death (SCD) in young athletes, with viral infection being the most common cause worldwide. Myocarditis recently has been reported as one of the cardiac complications of coronavirus disease 2019 (COVID-19) in athletes. Here we present a case of a 20-year-old male recreational soccer player with an episode of loss of consciousness in the context of respiratory infection. The patient reports having woken up with symptoms of an upper respiratory tract infection, and after playing a soccer match, he developed dizziness and a headache. He then suffered vasovagal syncope without loss of sphincter control. Physical examination, heart auscultation, peripheral and carotid pulses, and blood, microbiological/serological tests result on admission were normal. Moreover, no jugular engorgement at 45º, malleolar edema, or other heart failure signs were found. The 12-lead electrocardiogram (ECG), echocardiogram, 24-hour Holter-ECG did not reveal any significant finding. A cardiac magnetic resonance (CMR) was finally performed, revealing an abnormal signal increase was observed at the apical level in the short-tau inversion-recovery (STIR) and 4-chamber sequences. In addition, a pattern of apical fibrosis was observed in 4- and 2-chamber and short-axis late enhancement sequences for assessment of myocardial viability confirming the diagnosis of myocarditis. In athletes with suspected myocarditis, CMR seems to be a useful diagnostic tool, with excellent sensitivity for detecting inflammation, myocardial edema, and/or focal scarring.

Spanish Catheter Ablation Registry. 17th Official Report of the Spanish Society of Cardiology Working Group on Electrophysiology and Arrhythmias (2017).

INTRODUCTION AND OBJECTIVES: This report describes the findings of the 2017 Spanish Catheter Ablation Registry. METHODS: Data collection was retrospective. A standardized questionnaire was completed by each of the participating centers. RESULTS: A total of 15 284 ablation procedures were performed by 98 institutions (the highest number of ablations and institutions historically reported in this registry), with a mean of 156±126 and a median of 136 procedures per center. For the first time, the most frequently treated ablation target was atrial fibrillation (n=3457; 22.6%), followed by cavotricuspid isthmus (n=3449; 22.5%) and atrioventricular nodal re-entrant tachycardia (n=3429; 22.4%). The overall success rate was 87%. The rate of major complications was 2.6%, and the mortality rate was 0.09%. The percentage of procedures performed without fluoroscopic support increased to 6% of all ablations, and 2.3% of all ablations were performed in pediatric patients. CONCLUSIONS: The Spanish Ablation Catheter Registry systematically and uninterruptedly collects data on the ablation procedures performed in Spain, revealing that both the number of ablations and the number of centers performing them has progressively increased, while maintaining a high success rate and a low percentage of complications.

[Surgery ablation of atrial fibrillation with epicardial and endocardial biauricular radiofrequency: initial experience]. / Ablación quirúgica de la fibrilación auricular con radiofrecuencia biauricular epicárdico-endocárdica: experiencia inicial.

BACKGROUND: Atrial fibrillation is frequent in surgical patients with cardiac valvulopathies. Radiofrequency energy applied by means of surgical probes permits the reproduction of atriotomies described in the maze surgical procedure for the ablation of atrial fibrillation in a fast, safe and efficient way. This study presents our initial experience in treatment of chronic atrial fibrillation through radiofrequency performed in patients with surgical cardiac valvulopathies. PATIENTS AND METHOD: From June to November 2000, 10 patients, with surgical indications of valvulopathy, were intraoperatively treated through radiofrequency for its atrial fibrillation. Ablations were performed in the right auricle from the epicardium before starting extra corporeal circulation, and in the left auricle from the endocardium, while under circulation. Radiofrequency was applied through a surgical multielectrode probe. RESULTS: Eight patients (80%) presented some type of postoperative arrhythmia, with relapse of paroxysmal fibrillation in 3 patients and flutter in another one. At discharge, none of the patients presented relapse of chronic atrial fibrillation. There was no in-hospital mortality. After a mean follow-up of 3 months (range 1-6), 8 patients (80%) have recovered and maintained sinus rhythm. Only one patient has re-established echocardiographic biatrial contraction. CONCLUSIONS: Intraoperative radiofrequency has allowed us to perform the auricular lesions, in both auricles, in a simple way, with an initial effectiveness of 80%. Epicardial ablation of the right auricle was simple and safe. Although no patient presented relapse of chronic atrial fibrillation at hospital discharge, postoperative arrhythmias have continued to be the main postsurgical problem.

Clinical benefit of cardiac resynchronization therapy with a defibrillator in patients with an ejection fraction > 35% estimated by cardiac magnetic resonance.

INTRODUCTION AND OBJECTIVES: Cardiac resynchronization therapy with a defibrillator prolongs survival and improves quality of life in advanced heart failure. Traditionally, patients with ejection fraction > 35 estimated by echocardiography have been excluded. We assessed the prognostic impact of this therapy in a group of patients with severely depressed systolic function as assessed by echocardiography but with an ejection fraction > 35% as assessed by cardiac magnetic resonance. METHODS: We analyzed consecutive patients admitted for decompensated heart failure between 2004 and 2011. The patients were in functional class II-IV, with a QRS ≥ to 120 ms, ejection fraction ≤ 35% estimated by echocardiography, and a cardiac magnetic resonance study. We included all patients (n=103) who underwent device implantation for primary prevention. Ventricular arrhythmia, all-cause mortality and readmission for heart failure were considered major cardiac events. The patients were divided into 2 groups according to systolic function assessed by magnetic resonance. RESULTS: The 2 groups showed similar improvements in functional class and ejection fraction at 6 months. We found a nonsignificant trend toward a higher risk of all-cause mortality in patients with systolic function ≤ 35% at long-term follow-up. The presence of a pattern of necrosis identified patients with a worse prognosis for ventricular arrhythmias and mortality in both groups. CONCLUSIONS: We conclude that cardiac resynchronization therapy with a defibrillator leads to a similar clinical benefit in patients with an ejection fraction ≤ 35% or > 35% estimated by cardiac magnetic resonance. Analysis of the pattern of late gadolinium enhancement provides additional information on arrhythmic risk and long-term prognosis.