Integrated dilator-needle transseptal crossing device in atrial fibrillation cryoballoon ablation procedures.

INTRODUCTION: In cryoballoon ablation (CBA) procedures, transseptal access (TSA) is generally achieved using a standard sheath and needle system that is exchanged for the cryoballoon delivery sheath and dilator over a long wire. Sheath exchange has been related with air embolic events. Recently, an integrated dilator-needle system assembled to the cryoballoon sheath was introduced. We aimed to evaluate the efficacy and safety of an integrated TSA tool compared with the traditional approach in atrial fibrillation CBA procedures. METHODS: Patients scheduled for CBA procedures were randomized 1:1 to traditional TSA (t-TSA) or integrated TSA (i-TSA). TSA time was defined as time from superior vena cava to LA insertion of the cryoballoon delivery sheath, after sheath exchange (t-TSA) or directly (i-TSA). RESULTS: Ninety-seven patients (76 males, mean age 59 ± 10 years) were randomized, 48 patients underwent t-TSA, and 49 i-TSA. Mean TSA time was 5 min 59 s ± 5 min 36 s in the t-TSA group and 2 min 59 s ± 2 min 14 s in the i-TSA group (p < .001). Total fluoroscopy time, skin-to-skin procedure time, and LA dwell time were respectively 15 ± 6, 69 ± 16, and 44 ± 12 min in the t-TSA group and 13 ± 6, 65 ± 15, and 43 ± 11 min in the i-TSA group (p = ns). No clinically significant acute complications related to TSA were noted in both cohorts. CONCLUSION: This is the first randomized study comparing both TSA approaches. TSA in CBA procedures using this integrated tool enables a safe and efficient workflow, reducing TSA time and avoiding sheath exchange.

Left bundle branch pacing in alternating bundle branch block.

We present a case of symptomatic intermittent AV block showing during monitorization alternating bundle branch block. Presuming a high need of pacing, conduction system pacing was considered a more physiological alternative in this patient. Left bundle branch pacing restored a stable atrioventricular synchrony with a paced QRS complex similar to the native one and might be a good alternative in these cases.

Silent atrial fibrillation in pacemaker early post-implantation period: an unintentionally provoked situation?

Aims: Atrial high-rate episodes (AHREs) compatible with silent AF detected in pacemakers (PM) are related to an increased risk of stroke and silent ischaemic brain lesions (IBL) on CT scan. AHREs soon after PM implantation could be related with the procedure itself and the prognosis might be different. Methods and results: We analysed the incidence of AHREs >5 min and the presence of silent IBL in 110 patients (56% men, aged 75 ± 9 year-old) with PM and no history of AF, in relation to time from implantation (≤3 months vs. >3 months) and the atrial lead fixation (LF) (active vs. passive). Mean CHADS2 and CHA2DS2VASc scores were 1.9 ± 1.2 and 3.5 ± 1.5, respectively. Time from implantation was ≤3 months in 88 patients (80%). Active LF was used in 55 patients (50%). After 24 ± 9 months, AHREs were present in 40 patients (36.4%). CT-scan showed silent IBL in 26 patients (23.6%). The presence of AHREs at 3 months was more frequent in the patients with recent PM implantation (17% vs. 4.5%, P = 0.09) and significantly related to active LF (OR 5.36, 1.43-20.07; P < 0.05). The presence of silent IBL was related to the detection of AHREs during follow up (OR 3.12, 1.29-7.97; P < 0.05) but not with AHREs at first 3 months (OR 1.58, 0.49-5.05; P = 0.44). Conclusions: AHREs occur frequently during the first 3 months after PM implantation and could be related with procedure itself and the use of active LF. AHREs in this period might not be related to worse outcomes and should be interpreted cautiously.

Delta of the local ventriculo-atrial intervals at the septal location to differentiate tachycardia using septal accessory pathways from atypical atrioventricular nodal re-entry.

Aims: Tachycardia mediated by septal accessory pathways (AP) and atypical atrioventricular nodal re-entry (AVNRT) require careful electrophysiologic evaluation for differential diagnosis. We aim to describe the differential behaviour of local ventriculo-atrial (VA) intervals which predicts the tachycardia mechanism. Methods and results: The local VA intervals at the para-Hisian septum were measured under three different situations: (i) tachycardia; (ii) sustained entrainment from the right ventricular apex (RVA); and (iii) continuous pacing from the RVA during sinus rhythm. Differences were computed as follows: Δ-VAentr = VA during entrainment - VA during tachycardia; and Δ-VApac = VA while pacing during sinus rhythm - VA during tachycardia. In contrast to AVNRT, we hypothesized that an invariable retrograde conduction through the septal AP will keep the result of the subtractions close to 0 ms in cases of ortodromic atrioventricular re-entrant tachycardia (AVRT). We analysed 55 atypical AVNRT (45% posterior type) and 82 AVRT (10 anteroseptal, 18 para-Hisian, 12 mid-septal, and 42 posteroseptal). Δ-VAentr was longer for AVNRT (98.5 ± 40.3 ms) compared with septal AP (-5.7 ± 19.3 ms; P < 0.001). A value of 50 ms showed 98.7% sensitivity and 92% specificity (AUC 0.99; 95% CI 0.98-1). According to physiological criteria, a negative Δ-VAentr remains unobserved in the case of AVNRT (positive predictive value 100% for septal AP). Δ-VApac was also longer for AVNRT (66.5 ± 14.6 ms) compared with septal AP (-9.7 ± 3.3 ms; P < 0.001). A value of 50 ms showed 100% sensitivity and 74% specificity (AUC 0.86; 95% CI 0.76-0.93). Conclusions: Delta of the local VA intervals enables distinction between atypical AVNRT and AVRT mediated by septal AP.

CorVue algorithm efficacy to predict heart failure in real life: Unnecessary and potentially misleading information?

BACKGROUND: Heart failure (HF) hospitalizations have a negative impact on quality of life and imply important costs. Intrathoracic impedance (ITI) variations detected by cardiac devices have been hypothesized to predict HF hospitalizations. Although Optivol™ algorithm (Medtronic, Minneapolis, MN, USA) has been widely studied, CorVue™ algorithm's (St. Jude Medical, St. Paul, MN, USA) long-term efficacy has not been systematically evaluated in a "real-life" cohort. METHODS: CorVue™ was activated in implantable cardioverter defibrillator (ICD)/cardiac resynchronization therapy defibrillator (CRT-D) patients to store information about ITI measures. Clinical events (new episodes of HF requiring treatment and hospitalizations) and CorVue™ data were recorded every 3 months. Appropriate CorVue™ detection for HF was considered if it occurred in the 4 prior weeks to the clinical event. RESULTS: Fifty-three ICD/CRT-D (26 ICD and 27 CRT-D) patients (67 ± 1 years old, 79% male) were included. Device position was subcutaneous in 28 patients. At inclusion, mean left ventricular ejection fraction was 25 ± 7% and 27 patients (51%) were in New York Heart Association class I, 18 (34%) in class II, and eight (15%) in class III. After a mean follow-up of 17 ± 9 months, 105 ITI drops alarms were detected in 32 patients (60%). Only six alarms were appropriate (true positive) and required hospitalization. Eighteen patients (34%) presented 25 clinical episodes (12 hospitalizations and 13 emergency room/ambulatory treatment modifications). Nineteen of these clinical episodes (76%) remained undetected by the CorVue™ (false negative). Sensitivity of CorVue™ resulted in 24%, specificity was 70%, positive predictive value of 6%, and negative predictive value of 93%. CONCLUSIONS: CorVue™ showed a low sensitivity to predict HF events. Therefore, routinely activation of this algorithm could generate misleading information.

Inappropriate automatic mode switching episodes: What's the mechanism?

We present a case series of five patients reporting abnormal automatic mode switching (AMS) episodes during routinary cardiac defibrillator (ICD) and pacemaker (PM) follow-up. This non-previously described phenomenon was reported to St. Jude Medical (Abbott) Technical Support that confirmed the inappropriate automatic mode switching.

Solving difficulties in transseptal sheath crossing: The shoehorn technique.

The shoehorn technique is a simple and safe maneuver that can help to solve difficulties in challenging transseptal sheath crossing for atrial fibrillation cryoablation procedures.

Ivabradine for controlling heart rate in permanent atrial fibrillation: A translational clinical trial.

BACKGROUND: Pharmacological options for rate control in atrial fibrillation are scarce. Ivabradine was postulated to reduce the ventricular rate in this setting. OBJECTIVES: The objectives of this study were to evaluate the mechanism of inhibition of atrioventricular conduction produced by ivabradine and to determine its efficacy and safety in atrial fibrillation. METHODS: The effects of ivabradine on atrioventricular node and ventricular cells were studied by in vitro whole-cell patch-clamp experiments and mathematical simulation of human action potentials. In parallel, a multicenter, randomized, open-label, phase III clinical trial compared ivabradine with digoxin for uncontrolled permanent atrial fibrillation despite ß-blocker or calcium channel blocker treatment. RESULTS: Ivabradine 1 µM inhibited "funny" current and rapidly activating delayed rectifier potassium channel current by 28.9% and 22.8%, respectively (P < .05). The sodium channel current and L-type calcium channel current were reduced only at 10 µM. Ivabradine slowed the firing frequency of a modeled human atrioventricular node action potential by 10.6% and induced a minimal prolongation of ventricular action potential. Thirty-five (51.5%) patients were randomized to ivabradine and 33 (49.5%) to digoxin. The mean daytime heart rate decreased by 11.6 beats/min (-11.5%) in the ivabradine arm (P = .02) vs 19.6 (-20.6%) in the digoxin arm (P < .001), although the noninferiority margin of efficacy was not met (Z = -1.95; P = .97). The primary safety end point occurred in 3 patients (8.6%) on ivabradine and in 8 (24.2%) on digoxin (P = .10). CONCLUSION: Ivabradine produced a moderate rate reduction in patients with permanent atrial fibrillation. The inhibition of funny current in the atrioventricular node seems to be the main mechanism responsible for this reduction. Compared with digoxin, ivabradine was less effective, was better tolerated, and had a similar rate of serious adverse events.

EGC diagnosis of paroxysmal supraventricular tachycardias in patients without preexcitation.

This review is aimed at discussing the diagnostic value of the different electrocardiographic criteria so far described in the differential diagnosis of the major forms of paroxysmal supraventricular tachycardias (PSVTs). The predictive value of different combinations of these independent electrocardiographic (ECG) signs in distinguishing atrioventricular reentrant tachycardias (AVRTs) through a concealed accessory pathway (AP) versus atrioventricular nodal reentrant tachycardias (AVNRTs) are discussed in detail. In addition, the adjunctive diagnostic value of simple, bedside clinical variables and their combinations to the ECG interpretation in differentiating both tachycardia mechanisms is also reviewed.

Ictal asystole: A condition between neurology and cardiology.

Ictal asystole can appear in patients with focal epilepsy, even in early phases. We present our experience of 7 cases, remarking the electrocardiographic characteristics, the role of apnea, treatment and long-term evolution. Awareness of this entity and collaboration between neurologists and cardiologists are essential for a correct diagnosis and management.

Differential Responses of the Septal Ventricle and the Atrial Signals During Ongoing Entrainment: A Method to Differentiate Orthodromic Reciprocating Tachycardia Using Septal Accessory Pathways From Atypical Atrioventricular Nodal Reentry.

BACKGROUND: Differential diagnosis between tachycardia mediated by septal accessory pathways (AP) and atypical atrioventricular nodal reentry can be challenging. We hypothesized that an immediate versus delayed pace-related advancement of the atrial electrogram, once the local septal parahisian ventricular electrogram (SVE) has been advanced, may help in this diagnosis. METHODS AND RESULTS: We focused on differential timing between SVE and atrial signals at the initiation of continuous right ventricular apical pacing during tachycardia. SVE advancement preceding atrial reset was defined as SVE advanced by the paced wave fronts while atrial signal continued at the tachycardia cycle. We analyzed 51 atypical atrioventricular nodal reentry (45% posterior type) and 80 AP tachycardias (anteroseptal [10], parahisian [18], midseptal [12], and posteroseptal [40]). SVE advancement preceding atrial reset was observed in 98% of atrioventricular nodal reentries during 4±1.1 cycles; this phenomena was observed in 6 (8%) of the atrioventricular reentrant tachycardia mediated by septal AP (P<0.001; sensitivity 98%; specificity 93%; positive predictive value 90%; negative predictive value 99%) and lasted 1 single cycle (P<0.001). Right posteroseptal AP tachycardias were distinctly characterized by atrial reset preceding SVE advancement (with ventricular fusion; specificity 100%; positive predictive value 100%). In 11 cases, it was impossible to achieve sustain entrainment. In all of them, the differential responses at the entrainment attempt allowed for appropriate diagnosis. CONCLUSIONS: The differential response of the SVE and the atrial electrogram at the initiation of continuous right ventricular apical pacing during tachycardia effectively distinguishes between atypical atrioventricular nodal reentry and atrioventricular reentrant tachycardia mediated by septal APs.

Safety, long-term results, and predictors of recurrence after complete endocardial ventricular tachycardia substrate ablation in patients with previous myocardial infarction.

Conduction channels and electrograms with isolated component/late potentials are sensitive markers of the substrate of post-myocardial infarction sustained monomorphic ventricular tachycardia (VT). Ablation of all conduction channels and isolated component/late potentials (complete endocardial VT substrate ablation [CEVTSA]) during sinus rhythm could simplify and facilitate the ablation procedure, mainly in patients without references for clinical VT substrate identification. The aim of this study was to assess the safety, efficacy, and predictors of VT recurrence after CEVTSA. Electroanatomic mapping and CEVTSA were performed in 59 post-myocardial infarction patients (mean age 67 ± 9 years, mean left ventricular ejection fraction 30 ± 11%), 24 of whom did not have clinical VT substrate references. The mean areas of scar (≤1.5 mV) and dense scar (≤0.5 mV) were 76 ± 42 and 34 ± 24 cm(2), respectively; isolated component/late potentials and conduction channels were identified and ablated in 97% and 83% of patients (mean ablation area 14 ± 10 cm(2)). No life-threatening complications occurred during the procedure. After 1 year and at the end of follow-up (mean 39 ± 21 months), 81% and 58% of patients were free of VT. No differences were observed between patients with and without specific clinical VT substrate identification. Univariate analysis identified the left ventricular ejection fraction, VT cycle length (VTCL), infarct location (inferior vs anterior), and dense scar area as predictors of VT recurrence, and Cox analysis identified VTCL (hazard ratio 0.42, p <0.001) and dense scar area (hazard ratio 2.65, p <0.0006) as independent predictors. No patients with dense scar area ≤25 cm(2) and VTCL >350 ms had recurrences. In conclusion, CEVTSA is safe and effective, even in patients without clinical VT substrate identification. Scar area and VTCL are valuable predictors of VT recurrence.

Refining the indications of implantable cardioverter defibrillator in patients with left ventricular dysfunction.

Although clinical trials evaluating therapy with implantable cardioverter defibrillators (ICD) have had clear limitations, there are few interventions in which multiple trial settings over a long period have consistently produced a 20% to 30% reduction in total mortality in patients with left ventricular dysfunction. Substantial differences between the Guidelines on ICD implantation have resulted and the number of patients actually implanted following these recommendations remains relatively low. As well as this, different reasons have been proposed to explain why randomized trials of ICD versus control subjects implanted early after myocardial infarction do not show survival benefit. Moreover, many factors in addition to ejection fraction (EF) do influence the prognosis of patients with coronary disease. However, there are few tools to use this information to guide clinical decisions. Recent years have seen an ongoing debate on the further risk stratification of patients who will benefit most from ICD implantation and a combination of a few readily available clinical variables indicating advanced disease and comorbid conditions identifies ICD patients at high risk. In addition, the role of these devices in patients with nonischemic cardiomyopathies, in older patients and females, for prevention of sudden cardiac death (SCD), has long been debated. This review aims to summarize these criticisms and to refine the current indications of ICD implantation in patients with moderate-severe left ventricular dysfunction.

Taquicardia supraventricular paroxística inmediatamente tras un trasplante cardiaco / Paroxysmal supraventricular tachycardia immediately following heart transplantation

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