Electrical Excitation of the Pulmonary Venous Musculature May Contribute to the Formation of the Last Component of the High Frequency Signal of the P Wave

Pulmonary veins (PVs) have been shown to play an important role in the induction and perpetuation of focal AF. Fifty-one patients with AF, and 24 patients without AF as control subjects, were enrolled in this study. Signal-averaged P-wave recording was performed, and the filtered P wave duration (FPD), the root-mean-square voltage for the last 20, 30 and 40 ms (RMS20, 30, and 40, respectively) were compared. In 7 patients with AF, these parameters were compared before and after the catheter ablation. The FPD was significantly longer and the RMS20 was smaller in the patients with AF than those without AF. Because RMS30 was widely distributed between 2 and 10 µV, the AF group was sub-divided into two groups; Group 1 was comprised of the patients with an RMS30 ≧5.0 µV, and group 2, <5.0 µV. In group 1, short-coupled PACs were more frequently documented on Holter monitoring, and exercise testing more readily induced AF. After successful electrical disconnection between the LA and PVs, each micropotential parameter was significantly attenuated. These results indicate that the high frequency signal amplitude of the last component of the P wave is relatively high in patients with AF triggered by focal repetitive excitations most likely originating from the PVs. That is, attenuation by the LA-PV electrical isolation, and thus the high frequency P signals of the last component, may contain the electrical excitation of the PV musculature

Perioperative coronary artery spasms in patients undergoing catheter ablation of atrial fibrillation

博士（医学）甲日本医科大学202

The role of stress test for predicting genetic mutations and future cardiac events in asymptomatic relatives of catecholaminergic polymorphic ventricular tachycardia probands.

International audienceAIMS: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited arrhythmic disorder with a highly malignant clinical course. Exercise-stress test is the first-line approach to diagnose suspected individuals. We sought to elucidate the value of exercise-stress test for predicting mutations and future cardiac events in CPVT-family relatives. METHODS AND RESULTS: The present study included 67 asymptomatic relatives (24 ± 15 years) of 17 genetically positive CPVT probands, who underwent exercise-stress test without any medication and genetic testing. Exercise-stress test, which was considered positive with the induction of ventricular tachycardia or premature ventricular contractions consisting of bigeminy or couplets, was positive in 17 relatives (25%). Genetic analysis disclosed mutations in 16 of these 17 relatives (94%) and in 16 of the 50 relatives (32%) with negative exercise-stress test; the sensitivity and specificity for a positive genotype were 50 and 97%, respectively (P< 0.001). Among 32 mutation carriers, cardiac events occurred in 7 of the 16 relatives with positive and 2 of the 16 relatives with negative exercise-stress test during the follow-up period of 9.6 ± 3.8 years, and four with positive and two with negative stress test were not on regular beta-blocker treatment at these events. In the 16 relatives with positive stress test, those on beta-blocker treatment demonstrated a trend of lower cardiac event rate (Log-rank P= 0.054). CONCLUSION: In asymptomatic relatives of CPVT probands, exercise-stress test can be used as a simple diagnostic tool. Nevertheless, because of the low sensitivity for predicting mutations and future cardiac events in those with negative stress test, genetic analysis should be performed to improve patient management

Electrophysiological and anatomical background of the fusion configuration of diastolic and presystolic Purkinje potentials in patients with verapamil-sensitive idiopathic left ventricular tachycardia

Background: It is unclear whether false tendons (FTs) are a substantial part of the reentry circuit of verapamil-sensitive idiopathic left ventricular tachycardia (ILVT). This study aimed to prove the association between FTs and the slow conduction zone by evaluating the electro-anatomical relationship between the so-called diastolic Purkinje (Pd) potentials and FTs using an electro-anatomical mapping (EAM) system (CARTO). Methods: The 1st protocol evaluated the spatial distribution of Pd and presystolic Purkinje (Pp) potentials in 6 IVLT patients using a conventional CARTO system. In the remaining 2 patients (2nd protocol), the electro-anatomical relationship between the Pd–Pp fusion potential and the septal connection of the FT was evaluated using an EAM system incorporating an intra-cardiac echo (CARTO-Sound). Results: Pd potentials were observed in the posterior–posteroseptal region of the LV and had a slow conduction property, whereas Pp potentials were widely distributed in the interventricular (IV) septum. At the intersection of the 2 regions, which was located in the mid-posteroseptal area, both Pd and Pp potentials were closely spaced and often had a fused configuration. In the latter 2 patients (2nd protocol), it was confirmed that the intra-cardiac points at which the Pd–Pp fusion potential was recorded were located in the vicinity of the attachment site of the FT to the IV septum. In all patients, ILVTs were successfully eliminated by the application of radiofrequency at those points. Conclusion: FTs may at least partly contribute to the formation of the Pd potential, and thus form a critical part of the reentry circuit of ILVT

Incidence and risk factors of arrhythmic events in catecholaminergic polymorphic ventricular tachycardia.

International audienceBACKGROUND: The pathophysiological background of catecholaminergic polymorphic ventricular tachycardia is well understood, but the clinical features of this stress-induced arrhythmic disorder, especially the incidence and risk factors of arrhythmic events, have not been fully ascertained. METHODS AND RESULTS: The outcome in 101 catecholaminergic polymorphic ventricular tachycardia patients, including 50 probands, was analyzed. During a mean follow-up of 7.9 years, cardiac events defined as syncope, aborted cardiac arrest, including appropriate discharges from implantable defibrillators, or sudden cardiac death occurred in 27 patients, including 2 mutation carriers with normal exercise tests. The estimated 8-year event rate was 32% in the total population and 27% and 58% in the patients with and without beta-blockers, respectively. Absence of beta-blockers (hazard ratio [HR], 5.48; 95% CI, 1.80 to 16.68) and younger age at diagnosis (HR, 0.54 per decade; 95% CI, 0.33 to 0.89) were independent predictors. Fatal or near-fatal events defined as aborted cardiac arrest or sudden cardiac death occurred in 13 patients, resulting in an estimated 8-year event rate of 13%. Absence of beta-blockers (HR, 5.54; 95% CI, 1.17 to 26.15) and history of aborted cardiac arrest (HR, 13.01; 95% CI, 2.48 to 68.21) were independent predictors. No difference was observed in cardiac and fatal or near-fatal event rates between probands and family members. CONCLUSIONS: Cardiac and fatal or near-fatal events were not rare in both catecholaminergic polymorphic ventricular tachycardia probands and affected family members during the long-term follow-up, even while taking beta-blockers, which was associated with a lower event rate. Further studies evaluating concomitant therapies are necessary to improve outcome in these patients

Perioperative coronary artery spasms in patients undergoing catheter ablation of atrial fibrillation

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