A simplified approach for evaluating sustained slow pathway conduction for diagnosis and treatment of atrioventricular nodal reentry tachycardia in children and adults.

PURPOSE: During incremental atrial pacing in patients with atrioventricular nodal reentrant tachycardia, the PR interval often exceeds the RR interval (PR > RR) during stable 1:1 AV conduction. However, the PR/RR ratio has never been evaluated in a large group of patients with pacing from the proximal coronary sinus and after isoproterenol challenge. Our study validates new site of pacing and easier method of identification of PR > RR. MATERIAL AND METHODS: A prospective protocol of incremental atrial pacing from the proximal coronary sinus was carried out in 398 patients (AVNRT-228 and control-170). The maximum stimulus to the Q wave interval (S-Q = PR), SS interval (S-S), and Q-Q (RR) interval were measured at baseline and 10 min after successful slow pathway ablation and after isoproterenol challenge (obligatory). RESULTS: The mean maximum PR/RR ratios at baseline were 1.17 ±â€¯0.24 and 0.82 ±â€¯0.13 (p < 0.00001) in the AVNRT and controls respectively. There were no PR/RR ratios ≥1 at baseline and after isoproterenol challenge in 12.3% of the AVNRT group and in 95.9% of the control group (p < 0.0001). PR/RR ratios ≥1 were absent in 98% of AVNRT cases after slow pathway ablation/modification in children and 99% of such cases in adults (P = NS). The diagnostic performance of PR/RR ratio evaluation before and after isoproterenol challenge had the highest diagnostic performance for AVNRT with PR/RR > = 1 (sensitivity: 88%, specificity: 96%, PPV-97%, NPV-85%). CONCLUSIONS: The PR/RR ratio is a simple tool for slow pathway substrate and AVNRT evaluation. Eliminating PR/RR ratios ≥1 may serve as a surrogate endpoint for slow pathway ablation in children and adults with AVNRT.

Electrocardiographic algorithms to guide the management strategy of idiopathic outflow tract ventricular arrhythmias.

INTRODUCTION    The current guidelines of the European Society of Cardiology outlined electrocardiographic (ECG) differentiation of the site of origin (SoO) in patients with idiopathic ventricular arrhythmias (IVAs). OBJECTIVES    The aim of this study was to compare 3 ECG algorithms for differentiating the SoO and to determine their diagnostic value for the management of outflow tract IVA. PATIENTS AND METHODS    We analyzed 202 patients (mean age [SD]: 45 [16.7] years; 133 women [66%]) with IVAs with the inferior axis (130 premature ventricular contractions or ventricular tachycardias from the right ventricular outflow tract [RVOT]; 72, from the left ventricular outflow tract [LVOT]), who underwent successful radiofrequency catheter ablation (RFCA) using the 3­dimensional electroanatomical system. The ECGs before ablation were analyzed using custom­developed software. Automated measurements were performed for the 3 algorithms: 1) novel transitional zone (TZ) index, 2) V2S/V3R, and 3) V2 transition ratio. The results were compared with the SoO of acutely successful RFCA. RESULTS    The V2S/V3R algorithm predicted the left­sided SoO with a sensitivity and specificity close to 90%. The TZ index showed higher sensitivity (93%) with lower specificity (85%). In the subgroup with the transition zone in lead V3 (n = 44, 15 from the LVOT) the sensitivity and specificity of the V2-transition­ratio algorithm were 100% and 45%, respectively. The combined TZ index+V2S/V3R algorithm (LVOT was considered only when both algorithms suggested the LVOT SoO) can increase the specificity of the LVOT SoO prediction to 98% with a sensitivity of 88%. CONCLUSIONS    The combined TZ­index and V2S/V3R algorithm allowed an accurate and simple identification of the SoO of IVA. A prospective study is needed to determine the strategy for skipping the RVOT mapping in patients with LVOT arrhythmias indicated by the 2 combined algorithms.

Maximum voltage gradient technique for optimization of ablation for typical atrial flutter with zero-fluoroscopy approach.

Radiofrequency catheter ablation (RFCA) is an established effective method for the treatment of typical cavo-tricuspid isthmus (CTI)-dependent atrial flutter (AFL). The introduction of 3-dimensional electro-anatomic systems enables RFCA without fluoroscopy (No-X-Ray [NXR]). The aim of this study was to evaluate the feasibility and effectiveness of CTI RFCA during implementation of the NXR approach and the maximum voltage-guided (MVG) technique for ablation of AFL.Data were obtained from prospective standardized multicenter ablation registry. Consecutive patients with the first RFCA for CTI-dependent AFL were recruited. Two navigation approaches (NXR and fluoroscopy based as low as reasonable achievable [ALARA]) and 2 mapping and ablation techniques (MVG and pull-back technique [PBT]) were assessed. NXR + MVG (n  =  164; age: 63.7 ±â€Š9.5; 30% women), NXR + PBT (n  =  55; age: 63.9 ±â€Š10.7; 39% women); ALARA + MVG (n  =  36; age: 64.2 ±â€Š9.6; 39% women); and ALARA + PBT (n  =  205; age: 64.7 ±â€Š9.1; 30% women) were compared, respectively. All groups were simplified with a 2-catheter femoral approach using 8-mm gold tip catheters (Osypka AG, Germany or Biotronik, Germany) with 15 min of observation. The MVG technique was performed using step-by-step application by mapping the largest atrial signals within the CTI.Bidirectional block in CTI was achieved in 99% of all patients (P  =  NS, between groups). In NXR + MVG and NXR + PBT groups, the procedure time decreased (45.4 ±â€Š17.6 and 47.2 ±â€Š15.7 min vs. 52.6 ±â€Š23.7 and 59.8 ±â€Š24.0 min, P < .01) as compared to ALARA + MVG and ALARA + PBT subgroups. In NXR + MVG and NXR + PBT groups, 91% and 98% of the procedures were performed with complete elimination of fluoroscopy. The NXR approach was associated with a significant reduction in fluoroscopy exposure (from 0.2 ±â€Š1.1 [NXR + PBT] and 0.3 ±â€Š1.6 [NXR + MVG] to 7.7 ±â€Š6.0 min [ALARA + MVG] and 9.1 ±â€Š7.2 min [ALARA + PBT], P < .001). The total application time significantly decreased in the MVG technique subgroup both in NXR and ALARA (P < .01). No major complications were observed in either groups.Complete elimination of fluoroscopy is feasible, safe, and effective during RFCA of CTI in almost all AFL patients without cardiac implanted electronic devices. The most optimal method for RFCA of CTI-dependent AFL seems to be MVG; however, it required validation of optimal RFCA's parameters with clinical follow-up.

Simplified automated right ventricular overdrive pacing for rapid diagnosis of supraventricular tachycardia.

OBJECTIVES: The purpose of this study was to prospectively evaluate the feasibility and diagnostic value of right ventricular overdrive pacing (RVOP) during supraventricular tachycardia (SVT) using a 2-catheter approach with automatic pacing from the right ventricular inflow (RVIT) and outflow tract (RVOT). METHODS: One hundred and thirty-six consecutive patients (with 138 arrhythmias, mean age 36 ± 20 years, range 4-95) were enrolled in this study. Only coronary sinus and ablation catheters were used. RVOP was delivered from RVIT and then from RVOT. Each attempt consisted of 10 synchronized beats delivered at a cycle length of 10-40 ms longer than the tachycardia cycle length. RESULTS: RVOP was sufficient to confirm the transition zone within the first 9 beats in the majority of SVTs. Atrial perturbation (acceleration, delayed) in the transition zone was detected in all patients with orthodromic atrioventricular (AV) reentry. Patients with typical AV nodal reentry, atypical AV nodal reentry and atrial tachycardia did not show atrial timing perturbation during fusion complexes of RVOP. CONCLUSIONS: Synchronized RVOP from RVIT or RVOT is an easy and accurate method for the quick and reliable differential diagnosis of SVT in various clinical settings, particularly when only a limited number of catheters are used.

Feasibility of implementation of a "simplified, No-X-Ray, no-lead apron, two-catheter approach" for ablation of supraventricular arrhythmias in children and adults.

INTRODUCTION: Although the "near-zero-X-Ray" or "No-X-Ray" catheter ablation (CA) approach has been reported for treatment of various arrhythmias, few prospective studies have strictly used "No-X-Ray," simplified 2-catheter approaches for CA in patients with supraventricular tachycardia (SVT). We assessed the feasibility of a minimally invasive, nonfluoroscopic (MINI) CA approach in such patients. METHODS: Data were obtained from a prospective multicenter CA registry of patients with regular SVTs. After femoral access, 2 catheters were used to create simple, 3D electroanatomic maps and to perform electrophysiologic studies. Medical staff did not use lead aprons after the first 10 MINI CA cases. RESULTS: A total of 188 patients (age, 45 ± 21 years; 17% <19 years; 55% women) referred for the No-X-Ray approach were included. They were compared to 714 consecutive patients referred for a simplified approach using X-rays (age, 52 ± 18 years; 7% <19 years; 55% women). There were 9 protocol exceptions that necessitated the use of X-rays. Ultimately, 179/188 patients underwent the procedure without fluoroscopy, with an acute success rate of 98%. The procedure times (63 ± 26 vs. 63 ± 29 minutes, P > 0.05), major complications (0% vs. 0%, P > 0.05) and acute (98% vs. 98%, P > 0.05) and long-term (93% vs. 94%, P > 0.05) success rates were similar in the "No-X-Ray" and control groups. CONCLUSIONS: Implementation of a strict "No-X-Ray, simplified 2-catheter" CA approach is safe and effective in majority of the patients with SVT. This modified approach for SVTs should be prospectively validated in a multicenter study.

Lead-dependent infective endocarditis complicated by septic emboli.

Lead-dependent infective endocarditis (LDIE) has emerged as a serious complication of electrotherapy in the era of advanced medical technology and is a growing problem due to greater patient longevity, limited electrode life-time, an increasing number of abandoned leads, and subclinical symptoms. We present a case of dramatic course of LDIE in a 26 year-old patient in whom standard management had failed to cure endocarditis. This case was complicated by extensive pulmonary septic emboli and required cardio-thoracic intervention.

[Non-invasive electrophysiologic study and radiofrequency current ablation of tachycardia responsible for numerous inappropriate ICD interventions in patient with post-infarction dilated cardiomyopathy]. / Nieinwazyjne badanie elektrofizjologiczne i ablacja czestoskurczu bedacego przyczyna bardzo licznych interwencji ICD-DDD u chorego z pozawalowa kardiomiopatia rozstrzeniowa.

We present a case of 75-year-old man with numerous inappropriate interventions of an implanted cardioverter-defibrillator (ICD). In this patient with ischaemic cardiomyopathy, ICD was implanted for primary prevention of sudden cardiac death following recurrent syncope. ICD interrogation and non-invasive electrophysiologic study (NIPS) confirmed a risk of reentry-mediated tachycardia and excluded the presence of a manifest or concealed accessory pathway. Invasive electrophysiologic study revealed a wide zone that triggered atrioventricular nodal reentrant tachycardia, and ablation of the slow pathway resulted in complete remission of the arrhythmia. NIPS performed using atrial and ventricular ICD leads and subsequent ICD interrogation confirmed long-term effectiveness of the procedure. At the same time, clinical improvement of heart failure was seen, leading to a suspicion of tachycardia-induced cardiomyopathy coexisting with ischaemic cardiomyopathy.