Voltage mapping of Koch's triangle in atrioventricular nodal reentrant tachycardia ablation : Results from an observational multicenter prospective registry.

BACKGROUND: The identification of a "low-voltage bridge" to guide ablation of atrioventricular nodal reentry tachycardia (AVNRT) has been described as a safe and effective strategy in children. We investigated the presence of a low-voltage bridge in adult patients undergoing AVNRT ablation, to evaluate its anatomical correspondence with the successful ablation site. We also investigated the possible correlations between Koch's triangle anatomy and patients' biometric characteristics. METHODS: This observational registry prospectively collected data from 200 patients undergoing AVNRT ablation, guided by 3D electroanatomical mapping system, in 6 electrophysiology centers. Koch's triangle voltage map was collected; then, the anatomical correspondence between the low-voltage bridge and the successful ablation site was evaluated. Koch's triangle anatomical dimensions were subsequently drawn from the mapping system and correlated to patients' gender, age, and weight. RESULTS: The low-voltage bridge was identified in 159 over 200 procedures (79.5%). When the low-voltage bridge was identified, its anatomical correspondence with the successful ablation site has been proved in 137 over 159 cases (86%), with a reduction of radiofrequency deployment time. No strict correlations were found, on the other side, between Koch's triangle anatomy and patients' biometric data. CONCLUSIONS: The identification of the low-voltage bridge has proved to be a helpful strategy to guide AVNRT ablation in a large cohort of adult patients. Targeting the low-voltage bridge during AVNRT ablation helps to reduce RF application time. Koch's triangle morphological characteristics cannot be predicted on the base of patients' biometric data.

Optimization of coronary sinus lead placement targeted to right-to-left delay in patients undergoing cardiac resynchronization therapy.

AIMS: Anatomical placement of the coronary sinus (CS) lead in basal or mid-ventricular positions of the posterior and lateral walls is associated with a better clinical outcome of cardiac resynchronization therapy (CRT). We hypothesized that optimization of CS lead placement targeted the right-to-left electrical delay (RLD) predicts an additional clinical benefit. METHODS AND RESULTS: The CS lead was placed according to current standards in 90 patients (Conventional group) and at the site of the longest RLD in 121 patients (RLD group). Non-responders were defined as those who died or underwent hospitalization for heart failure or did not improve in their Clinical Composite Score within 6 months. There were 67 (32%) non-responders. Compared with Conventional group, the final CS pacing site was more frequently in the basal segments in the RLD group (40% vs. 23%, P = 0.007); moreover, the RLD ratio (%RLD) of the total QRS width was longer (77 ± 13 vs. 73 ± 15, P = 0.05) and biventricular QRS shortened more from the baseline (-31 ± 21 ms vs. -21 ± 26 ms, P = 0.004). Nevertheless, the rate of non-responders was similar in the RLD and Conventional groups (35% vs. 28%, P = 0.30), as was %RLD (76 ± 16 vs. 75 ± 13, P = 0.66). QRS width during right ventricular (RV) pacing was an independent predictors of adverse outcome, with a 2% increase in the risk of failure for each 1 ms increase in QRS (P = 0.006). CONCLUSION: Optimization of CS lead placement targeted to latest electrical activation does not provide additional clinical benefit to anatomical placement in basal or mid-ventricular positions of the posterior and lateral walls. QRS width during RV pacing was a strong predictor of CRT failure. CLINICAL TRIAL REGISTRATION: http://www.clinicaltrials.gov. Unique identifier: NCT03204864.

Optimization of coronary sinus lead placement targeted to the longest right-to-left delay in patients undergoing cardiac resynchronization therapy: The Optimal Pacing SITE 2 (OPSITE 2) acute study and protocol.

AIMS: Left ventricular (LV) lead positioning at the site of delayed electrical activation is associated with better response to cardiac resynchronization therapy (CRT). We hypothesized that a long electrical conduction delay between right ventricular (RV) and coronary sinus (CS) leads during RV pacing (RLD index) is correlated with a better clinical outcome METHODS AND RESULTS: RLD is measured intraprocedurally, during RV pacing, as the time interval between the intracardiac electrograms of RV and CS leads. Initially, we did a prove-of-concept, feasibility, acute study in 97 patients who underwent CRT implantation. The CS lead position was assessed in the 40° right anterior oblique and 40° left anterior oblique views and assigned to one of 11 prespecified segments of a schematic eyeball depiction of the LV walls. Acute outcomes were QRS width during biventricular (BIV) pacing. The longest RLD were found in the basal and mid lateral segments; these accounted for 82% and 78%, respectively, of the total QRS width (%RLD). %RLD was inversely correlated with BIV-paced QRS (P  =  0.0001). A similar slope was present either in the 78 patients with preserved atrioventricular (AV) conduction and in the 19 without AV conduction (- 0.34 vs - 0.27, P  =  0.7). CONCLUSION: We showed that RLD can be used to guide lead placement at the time of CRT implantation and that it is correlated with BIV-QRS width, an indirect predictor of clinical outcome. Based on these findings we started the prospective, multicenter Optimal Pacing SITE 2 (OPSITE 2) trial with the objective to demonstrate a relationship between RLD and clinical outcomes assessed as death, hospitalization for heart failure, New York Heart Association class, and clinical composite score. The protocol is provided.

Stroke incidence in patients with cardiac implantable electronic devices remotely controlled with automatic alerts of atrial fibrillation. A sub-analysis of the HomeGuide study.

BACKGROUND: Remote Monitoring (RM) of cardiac implantable electronic devices (CIEDs) is recommended in management of Atrial Fibrillation (AF), which is a recognized risk factor for thromboembolism. We tried to elucidate whether stroke incidence observed in a large, remotely monitored population was consistent with the CHA2DS2VASc risk profile. METHODS: Data from 1650 patients [76% male, age 72 (63-68), CHA2DS2VASc score 3.0 (2.0-4.0)] enrolled during the HomeGuide study and monitored with a daily-transmission RM system providing automatic alerts for AF, were analysed. Of those, 25% had a pacemaker and 75% an implantable cardioverter defibrillator with or without cardiac resynchronization. Estimations of the expected thromboembolic events were based on the population CHA2DS2VASc score profile used in a computer-simulated Markov model. RESULTS: Eight thromboembolic events were observed with a 4-year cumulative stroke rate of 0.8% (confidence interval, 0.4%-1.5%). Simulations returned from 18.7 to 17.1 expected events, depending on the AF duration assumed to trigger anticoagulation (one-sample log-rank p<0.03). During the study period, 681 (84%) AF episodes and 129 (16%) atrial tachycardias were detected in 291 patients (18%): 93% of episodes were detected remotely in 269 patients, 66% of whom had no history of AF. Medical interventions were necessary in 305 episodes, 85% of which were detected remotely. Reaction time was 1 (0-6) days for remotely-detected episodes and 33 (14-121) days for episodes detected in clinic (p<0.0001). CONCLUSIONS: In a large CIED population followed remotely for up to 4years, the incidence of thromboembolic events was less than half the estimations based on the CHA2DS2VASc risk profile.

The progression of left ventricular systolic and diastolic dysfunctions in hypertrophic cardiomyopathy: clinical and prognostic significance.

OBJECTIVES: The significance of the progression of systolic and diastolic dysfunctions in hypertrophic cardiomyopathy (HCM) is still an open issue. We sought to evaluate the clinical and prognostic implications of the progression of left ventricular systolic and diastolic dysfunction in HCM. METHODS: One hundred one HCM patients were studied by echo-Doppler at baseline and during follow-up. RESULTS: During a follow-up of 109 + or - 67 months, 28% of patients showed a progression to left ventricular diastolic dysfunction, defined as restrictive filling pattern (RFP), and 16% to left ventricular systolic dysfunction (left ventricular ejection fraction <50%). The 10-year heart transplant-free survival rate was 45% in patients with RFP at follow-up vs. 82% in the patients without RFP (P < 0.001), and 52% in patients with left ventricular systolic dysfunction at follow-up vs. 75% in the patients with left ventricular ejection fraction of at least 50% (P = 0.001). Baseline predictors of death/transplantation were New York Heart Association class III-IV, indexed left atrial diameter, and RFP. When RFP and left ventricular systolic dysfunction were added at follow-up, both emerged as prognostic predictors (RFP: hazard ratio 8.92, 95% confidence interval 2.5-31.86; systolic dysfunction: hazard ratio 25.35, 95% confidence interval 3.57-179.88) with a significant increase of area under the receiver-operating characteristic curves (0.81 vs. 0.70, P = 0.03) with respect to the baseline model. CONCLUSION: Left ventricular diastolic and/or systolic dysfunction at follow-up are relatively frequent in HCM and are associated with a poor prognosis.