His bundle pacing: A promising alternative strategy for anti-bradycardic pacing - report of a single-center experience.

His bundle pacing (HBP) is proven to be a safe and effective alternative pacing modality that, in addition, avoids pacemaker-induced cardiomyopathy (PICM) by achieving a "physiological" ventricular stimulation, via the native conduction system. Indications include various causes of bradycardia requiring anti-bradycardic pacing, inadequately controlled atrial fibrillation requiring AV node ablation and established PICM. In addition, HBP may also be used as an alternative therapy for patients with heart failure (HF) and an indication for cardiac resynchronization therapy (CRT). Available data show several advantages of HBP with regard to preservation or restoration of intra- and inter-ventricular synchronization; improvement in left ventricular ejection fraction, functional status and quality of life; decrease in atrial fibrillation incidence and improvement in HF hospitalization rates, compared with conventional pacing. Nevertheless, superiority in terms of mortality rates has not been consistently demonstrated, and the long-term efficacy and safety of HBP remain to be proven. In the present manuscript, we review the status of HBP and present our current experience with this novel pacing modality.

Programmed ventricular stimulation predicts arrhythmic events and survival in hypertrophic cardiomyopathy.

BACKGROUND: Sudden cardiac death (SCD) risk stratification in hypertrophic cardiomyopathy (HCM) in the context of primary prevention remains suboptimal. The purpose of this study was to examine the additional contribution of programmed ventricular stimulation (PVS) on established risk assessment. METHODS: Two-hundred-and-three consecutive patients with diagnosed HCM and ≥1 noninvasive risk factors were prospectively enrolled over 19years. Patients were risk stratified, submitted to PVS and received an implantable cardioverter-defibrillator (ICD) according to then-current American Heart Association (AHA) guidelines and inducibility. Participants were prospectively followed-up for primary endpoint occurrence (appropriate ICD therapy or SCD). Contemporary (2015) AHA and European Society of Cardiology (ESC) guidelines were retrospectively assessed. RESULTS: During a median follow-up period of 60months the primary endpoint occurred in 20 patients, 19 of whom were inducible and received an ICD. Overall, 79 patients (38.9%) were inducible and 92 patients (45.3%) received an ICD (PVS sensitivity=95%, specificity=67.2%, positive predictive value=24%, negative predictive value=99.2%). AHA and ESC guidelines application misclassified 3 and 9 primary endpoint-meeting patients, respectively. Inducibility was the most important determinant of event-free survival in multivariate Cox regression (hazard ratio=33.3). A combined approach of ESC score≥6% or AHA indication for ICD with PVS inducibility yielded absolute sensitivity and negative predictive value, the former at a more cost-effective and specific way. CONCLUSIONS: Inducibility at PVS predicts SCD or appropriate device therapy in HCM. Non-inducibility is associated with prolonged event-free survival, while the procedure was proven safe. Reintegration of PVS into established risk stratification models in HCM may improve patient assessment.

Diagnosis and management of phantom tachycardias based on an electrophysiologically guided approach.

BACKGROUND: Non-documented palpitations, or phantom tachycardias, are palpitations deemed to be of unknown origin after evaluation with conventional diagnostic tools, such as 12-lead electrocardiogram and Holter recordings. Our aim was to determine the diagnostic value of an electrophysiologic study (EPS) and its role in the management of patients presenting with non-documented palpitations. METHODS: We performed EPS in 78 consecutive patients with repeatable, poorly tolerated symptoms of paroxysmal, non-documented tachycardia, the absence of structural heart disease and at least one 24-h Holter recording. The duration and frequency of palpitations was registered in each patient. RESULTS: Long-lasting palpitations (>1 hour) were present in 15.4% of patients. Half of patients reported symptoms less often than once per week. Only 13/78 patients (16.6%) had normal EPS findings, while dual pathways at the AV node ± echo beats were identified in another 13 patients without inducible tachycardia. At least one tachycardia event was induced in 52 patients (66.6%). AVNRT was provoked in 32 patients (41.2%). Ablation was performed in 14/52 patients with inducible tachycardia (26.9%). Slow pathway ablation was also performed in three patients with dual AV pathways and atrial echo-beats but without provoked tachycardia. Follow-up data were available in 52 patients, and 84.6% had fewer or no clinical recurrences. CONCLUSIONS: EPS is safe and of enhanced diagnostic value in patients with unexplained palpitations because only 1/6 had negative results. EPS also provided an explanation about the mechanism of arrhythmia and successfully guided the management of these patients, as well as enhanced improvement in the quality of life.

Correlation of noninvasive electrocardiography with invasive electrophysiology in syncope of unknown origin: implications from a large syncope database.

BACKGROUND: The evaluation of syncope can be expensive, unfocussed, and unrevealing yet, failure to diagnose an arrhythmic cause of syncope is a major problem. We investigate the utility of noninvasive electrocardiographic evaluation (12-lead ECG and 24-hour ambulatory electrocardiographic recordings) to predict electrophysiology study results in patients with undiagnosed syncope. METHODS: We evaluated 421 patients with undiagnosed syncope who had an electrocardiogram (ECG), an electrophysiology study, and 24-hour ambulatory monitoring. Noninvasive testing was used to predict electrophysiology testing outcomes. Multivariable logistic regression analysis adjusting for age, sex, presence of heart disease, and left ventricular ejection fraction (LVEF) was used to assess independent predictors for sinus node disease, atrioventricular node disease, and induction of ventricular tachyarrhythmias. RESULTS: Patients were divided into four groups: group 1, abnormal ECG and ambulatory monitor; group 2, abnormal ECG only; group 3, abnormal ambulatory monitor; and group 4, normal ECG and ambulatory monitor. The likelihood of finding at least one abnormality during electrophysiologic testing among the four groups was highest in group 1 (82.2%) and lower in groups 2 and 3 (68.1% and 33.7%, respectively). In group 4, any electrophysiology study abnormality was low (9.1%). Odds ratios (OR) were 35.9 (P < 0.001), 17.8 (P < 0.001), and 3.5 (P = 0.064) for abnormal findings on electrophysiology study, respectively (first three groups vs the fourth one). ECG and ambulatory monitor results predicted results of electrophysiology testing. CONCLUSION: Abnormal ECG findings on noninvasive testing are well correlated with potential brady- or/and tachyarrhythmic causes of syncope, in electrophysiology study of patients with undiagnosed syncope.