Nuria Rivas-Gándara

Differences in the yield of the implantable loop recorder between secondary and tertiary centers

BACKGROUND The implantable loop recorder (ILR) is a useful tool for diagnosis of syncope or palpitations. Its easy use and safety have extended its use to secondary hospitals (those without an Electrophysiology Lab). The aim of the study was to compare results between secondary and tertiary hospitals. METHODS National prospective and multicenter registry of patients with an ILR inserted for clinical reasons. Data were collected in an online database. The follow-up ended when the first diagnostic clinical event occurred, or 1 year after implantation. Data were analyzed according to the center of reference; hospitals with Electrophysiology Lab were considered Tertiary Hospitals, while those hospitals without a lab were considered Secondary Hospitals. RESULTS Seven hundred and forty-three patients (413 [55.6%] men; 65 ± 16 year-old): 655 (88.2%) from Tertiary Centers (TC) and 88 (11.8%) from Secondary Centers (SC). No differences in clinical characteristics between both groups were found. The electrophysiologic study and the tilt table test were conducted more frequently in Tertiary Centers. Follow-up was conducted for 680 (91.5%) patients: 91% in TC and 94% in SC. There was a higher rate of final diagnosis among SC patients (55.4% vs. 30.8%; p < 0.001). Tertiary Hospital patients showed a trend towards a higher rate of neurally mediated events (20% vs. 4%), while bradyarrhythmias were more frequent in SC (74% vs. 60%; p = 0.055). The rate of deaths and adverse events was similar in both populations. CONCLUSIONS Patients with an ILR in SC and TC have differences in terms of the use of complementary tests, but not in clinical characteristics. There was a higher rate of diagnosis in Secondary Hospital patients.

A risk score to predict the absence of left ventricular reverse remodeling: Implications for the timing of ICD implantation in primary prevention

BACKGROUND A prophylactic implantable cardioverter defibrillator (ICD) in patients with heart failure and reduced left ventricular ejection fraction (HFrEF) is only indicated when left ventricular ejection fraction (LVEF) reassessment remains ≤35% after 3-6 months on optimal pharmacological therapy. However, LVEF may not improve during this period and the patient may be exposed to an unnecessary risk of sudden cardiac death. This study aimed to determine the incidence and predictors of the absence of left ventricular reverse remodeling (LVRR) after pharmacological treatment optimization in patients with HFrEF to design a risk score of absence of LVRR. METHODS Consecutive outpatients with LVEF ≤35% were included in this observational prospective study. Up-titration of angiotensin-converting enzyme (ACE) inhibitors/angiotensin II receptor blockers (ARBs), beta-blockers, mineralocorticoid receptor antagonists (MRAs), and ivabradine was performed in our Heart Failure (HF) Unit. The absence of LVRR was defined as the persistence of an LVEF ≤35% at the 6-month follow-up. RESULTS One hundred and twenty patients were included. At the 6-month follow-up, 64%, 76%, 72%, and 7% of patients were at 100% of the target dose of ACE inhibitors/ARBs, beta-blockers, MRAs, and ivabradine, respectively. LVRR was observed in 48% of the patients. Ischemic cardiomyopathy, prolonged HF duration, and larger left ventricular end-diastolic diameter index (LVEDDI) were independent predictors of the absence of LVRR. The risk score based on these predictors showed a c-statistic value of 0.81. CONCLUSIONS Pharmacological treatment optimization is associated with LVRR in approximately half of cases, reducing potential ICD indications in parallel. However, ischemic cardiomyopathy, prolonged HF duration, and larger LVEDDI predict the absence of LVRR and favor ICD implantation without delay. The risk score based on the former predictors may help the clinician with the timing of ICD implantation.

Diagnostic Yield and Economic Assessment of a Diagnostic Protocol With Systematic Use of an External Loop Recorder for Patients With Palpitations

INTRODUCTION AND OBJECTIVES To assess the diagnostic yield and cost-effectiveness of a diagnostic protocol based on the systematic use of latest-generation external loop recorders (ELRs) compared with the classic diagnostic strategy for patients with recurrent unexplained palpitations. METHODS Two cohorts of consecutive patients referred for diagnosis of unexplained palpitations to the outpatient clinic of the arrhythmia unit were compared: a prospective cohort after the implementation of a new diagnostic protocol based on the systematic use of ELRs, and another, retrospective, cohort before the implementation of the protocol. The cost of diagnosis was calculated based on the number of complementary examinations, visits to outpatient clinics, or emergency department visits required to reach a diagnosis, and its costs according the prices published for the local health system. RESULTS One hundred and forty-nine patients were included (91 in the ELR group, 58 in the control group). The diagnostic yield was higher in the ELR group (79 [86.8%] definitive diagnoses in the ELR group vs 12 [20.7%] in the control group, P < .001). The cost per diagnosis was €375.13 in the ELR group and €5184.75 in the control group (P < .001). The cost-effectiveness study revealed that the systematic use of ELR resulted in a cost reduction of €11.30 for each percentage point of increase in diagnosis yield. CONCLUSIONS In patients with recurrent unexplained palpitations, evaluation by means of a study protocol that considers the systematic use of a latest-generation ELR increases diagnostic yield while reducing the cost per diagnosis.

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.

Predictors of Acute Failure Ablation of Intra‐atrial Re‐entrant Tachycardia in Patients With Congenital Heart Disease: Cardiac Disease, Atypical Flutter, and Previous Atrial Fibrillation

Background Intra‐atrial re‐entrant tachycardia (IART) in patients with congenital heart disease (CHD) increases morbidity and mortality. Radiofrequency catheter ablation has evolved as the first‐line treatment. The aim of this study was to analyze the acute success and to identify predictors of failed IART radiofrequency catheter ablation in CHD. Methods and Results The observational study included all consecutive patients with CHD who underwent a first ablation procedure for IART at a single center from January 2009 to December 2015 (94 patients, 39.4% female, age: 36.55±14.9 years). In the first procedure, 114 IART were ablated (acute success: 74.6%; 1.21±0.41 IART per patient) with an acute success of 74.5%. Cavotricuspid isthmus–related IART was the only arrhythmia in 51%; non–cavotricuspid isthmus–related IART was the only mechanism in 27.7% and 21.3% of the patients had both types of IART. Predictors of acute radiofrequency catheter ablation failure were as follows: nonrelated cavotricuspid isthmus IART (odds ratio 7.3; confidence interval [CI], 1.9–17.9; P=0.04), previous atrial fibrillation (odds ratio 6.1; CI, 1.3–18.4; P=0.02), transposition of great arteries (odds ratio, 4.9; CI, 1.4–17.2; P=0.01) and systemic ventricle dilation (odds ratio 4.8; CI, 1.1–21.7; P=0.04) with an area under the receiver operating characteristic curve of 0.83±0.056 (CI, 0.74–0.93, P=0.001). After a mean follow‐up longer than 3.5 years, 78.3% of the patients were in sinus rhythm (33.1% of the patients required more than 1 radiofrequency catheter ablation procedure). Conclusions Although ablation in CHD is a challenging procedure, acute success of 75% can be achieved in moderate–highly complex CHD patients in a referral center. Predictors of failed ablation are IART different from cavotricuspid isthmus, previous atrial fibrillation, and markers of complex CHD (transposition of great arteries, systemic ventricle dilation).

Predictors of positive electrophysiological study in patients with syncope and bundle branch block: PR interval and type of conduction disturbance

Electrophysiological study (EPS) is indicated in patients with syncope and bundle branch block (BBB). Data about predictors of positive EPS in these patients is scarce.

Mechanisms of Intra-Atrial Re-Entrant Tachycardias in Congenital Heart Disease: Types and Predictors

Intra-atrial re-entrant tachycardia (IART) is a severe complication in patients with congenital heart disease (CHD). Cavotricuspid isthmus (CTI)-related IART is the most frequent mechanism. However, due to fibrosis and surgical scars, non-CTI-related IART is frequent. The main objective of this study was to describe the types of IART, circuit locations, and to analyze predictors of CTI versus non-CTI-related IART. This is an observational study that includes all consecutive patients with CHD who underwent a first IART ablation in a single referral tertiary hospital from January 2009 to December 2015 (94 patients; 39.4% women; age: 36.55 ± 14.9 years, 40.4% with highly complex cardiac disease). During the study, 114 IARTs were ablated (1.21 ± 0.41 IARTs per patient). CTI-related IART was the only arrhythmia in 51% (n = 48) of patients; non-CTI-related IART was the only mechanism in 27.7% (n = 26), and 21.3% of patients (n = 20) presented the two types of IART. Severe dilation of the systemic ventricle, absence of severe dilation of the venous atrium, highly complex cardiac defects, and nontypical electrocardiography (ECG) were related to non-CTI-related IART in univariate analysis. In multivariate analysis, nontypical ECG (odds ratio 3.64; 1.01 to 4.9; p = 0.049) and grade III CHD complexity (odds ratio 9.43; 1.44 to 11.7; p = 0.001) were predictors of non-CTI-related IART. In conclusion, in our population with a high proportion of complex CHD, CTI-related IART was the most frequent mechanism, although non-CTI-related IART was present in 49% (alone or with concomitant CTI-related IART). High-grade CHD complexity and nontypical ECG were strongly related to non-CTI IART.

Life-threatening and life-saving inappropriate implantable cardioverter defibrillator shocks

An implantable cardioverter defibrillator (ICD) lead dislodgement into the right atrium is a dangerous situation, particularly in patients in atrial fibrillation because atrial fibrillation can be sensed as ventricular fibrillation and true ventricular fibrillation induced with an inappropriate shock. In the presence of shocks, ICD interrogation should be performed as soon as possible.

Narrow Complex Tachycardia with Irregular Ventricular and Atrial Intervals: What Is the Mechanism?

A 46-year-old woman with recurrent episodes of supraventricular tachycardia was referred for electrophysiological study and catheter ablation. Her 12-lead electrocardiogram was normal and she had no structural heart disease. After informed consent was obtained, electrophysiological testing was performed in the drug-free, postabsortive nonsedated state. Two multipolar catheters were introduced into the right femoral vein and placed in the coronary sinus and in the His bundle region. Baseline conduction intervals were within normal limits: atrial-His (A-H) interval 65 ms and His-ventricle (H-V) interval 44 ms. There was decremental retrograde ventriculoatrial (VA) conduction with a concentric atrial activation pattern. Programmed atrial stimulation from the coronary sinus revealed dual atrioventricular (AV) nodal conduction physiology, and a nonsustained narrow complex tachycardia was reproducibly induced with a previous jump in the A-H interval (Fig. 1). Following isoproterenol administration, runs of tachycardia were longer but still nonsustained, so pacing maneuvers during tachycardia could not be performed. Figure 2 shows a long run of tachycardia, with apparent V-A dissociation (fewer atrial than ventricular beats) and irregular atrial and ventricular cycle lengths. Atrial activation was concentric in the coronary sinus catheter, with earliest activation simultaneous at the His bundle region and the coronary sinus ostium. What is the most likely mechanism of this tachycardia?