Chikaya Omichi

Comparison of clinical features and prognosis of cardiac sarcoidosis and idiopathic dilated cardiomyopathy

In the present study, clinical findings of 15 patients with cardiac sarcoidosis presenting as dilated cardiomyopathy were compared with those of 30 consecutive patients with idiopathic dilated cardiomyopathy. The sarcoidosis patients had different clinical features, including female predominance, a high incidence of grave conduction disturbance and abnormal wall thickness, uneven wall motion abnormalities, and perfusion defects preferentially affecting the anteroseptal and apical regions, and poor prognosis compared with those with idiopathic dilated cardiomyopathy.

Effect of radiofrequency catheter ablation on parasympathetic denervation : a comparison of three different ablation sites

Radiofrequency (RF) catheter ablation of supraventricular tachycardias (SVT) has been shown to result in local parasympathetic denervation. The purpose of this study was to estimate the correlation between RF cumulative energy and parasympathetic denervation at three different ablation sites. Methods: 45 patients who underwent RF ablation of 36 AV reentrant tachycardias and 9 AV nodal reentrant tachycardias were studied. Twenty patients had left free‐wall accessory pathways (group L), 8 patients right free‐wall accessory pathways (group R), and 17 patients septal accessory path ways (n = 8) or slow pathways (n ‐9)(groupS). Time and frequency domain analysis of heart rate variability on 24‐hour ambulatory ECG recordings was performed before and after RF ablation, pNN50 and the high frequency (0.15 to 0.40 Hz, HF) component were measured to examine the effects on parasympathetic nerve activity. The values of Δ pNN50 and Δ HF were expressed as the percent change of pNN50 and HF that occurred after versus before RF ablation. Results: Both pNN50 and HF significantly decreased after RF ablation in all three groups. In group S, there was a significant correlation between RF cumulative energy and Δ pNN50r = 0.66, P < 0.01) or Δ HF (r = 0.58, P < 0,05). In contrast, there was no correlation between RF cumulative energy and Δ pNNSO or Δ HF in either group L or group R. Conclusion: These data suggest that RF ablation produces parasympathetic denervation at all three sites along the mitral or tricuspid annulus and that parasympathetic fibers may be located predominantly in the septal area.

Electrophysiological features of Atrial tachycardia arising from the atrioventricular annulus

MATSUOKA, K., et al.: Electrophysiological Features of Atrial Tachycardia Arising from the Atrioven‐tricular Annulus. Atrial tachycardia (AT) arises from various sites in the atrium and the mechanisms are nonuniform. McGuire et al. reported that the cells around the atrioventricular annuli resembled nodal cells in their cellular electrophysiology. The purpose of this study was to delineate the electrophysiological features of AT arising from the atrioventricular (AV) annulus (AVAT). The study included five patients with six AVATs that were abolished by the radiofrequency energy delivery. The location of the AV annuli was defined by using the AV ratio of the local electrograms and the amplitude of the ventricular electrograms, in addition to the anatomic findings under fluoroscopic guidance. The tachycardia cycle lengths were 403 ± 117 ms. An AV ratio of the electrograms at the successful ablation sites was 0.4 ± 0.4 at the tricuspid annulus and 1.5 ± 0.3 at the mitral annulus. Small doses (mean 3.2 ± 1.8 mg) of adenosine triphosphate could terminate all the tachycardia episodes for five of the ATs without the development of AV nodal conduction block. The successful ablation sites were located at the right mid‐septum in 1 AT, right posteroseptum in 2 ATs, right posterolateral region in 1 AT, and left anteroseptum in 2 ATs. These findings suggest that the cells with nodal‐type action potentials around both annuli might play an important role in the genesis of AVAT.

Electrophysiological determinants of persistent dual atrioventricular nodal pathway physiology after slow pathway ablation in atrioventricular nodal reentrant tachycardia.

The purpose of this study was to examine the electrophysiological determinants of the elimination of recurrent atrioventricular nodal reentrant tachycardia (AVNRT) despite the persistence of dual AV nodal pathway physiology or single echo beats after ablation procedures. The study included 26 patients with common AVNRT who had undergone successful ablation treatment and no long‐term recurrence of AVNRT. The slow pathway potential was targeted, and the endpoint of ablation was one echo during atrial extrastimulus testing (ET) with isoproterenol. Persistent dual pathways physiology or single echoes were present in 12 patients (group I) and absent in 16 (group II) after ablation. The number of anterograde AV nodal pathways and maximum AH interval (Max AH) during ET were measured before and after ablation, and ventriculoatrial conduction during ventricular pacing was examined. Results: (1) multiple AV nodal pathways were more frequently observed in group I than in group II (50.0% vs 7%, P < 0.05); (2) Max AH decreased significantly after ablation in both groups (309 ± 157 vs 171 ±53 ms in group II; P < 0.01, and 409 ± 65 vs 274 ± 86 ms in group I; P < 0.001); and (3) retrograde dual pathway conduction was more common in group I than in group II. These data suggest the presence of nonuniform conductive properties of the AV node in group I and that ablation targeting the slow pathway potential prevents recurrences of AVNRT by eliminating the pathway with the longest conduction time.

Changes in autonomic nervous activity after catheter ablation of atrial tachycardia arising from the atrioventricular annulus

Radiofrequency (RF) catheter ablation of supraventricular tachycardias causes local parasympathetic denervation. This study used heart rate variability (HRV) to evaluate the effects of ablation of atrial tachycardia (AT) arising from the atrioventricular annulus (AVAT) on autonomic function. Ten patients with AVAT were referred for ablation (group AT) and compared with 8 patients with paroxysmal atrial fibrillation who underwent PV isolation (group Paf), and 13 patients with idiopathic ventricular tachycardia successfully treated by ablation (group VT). Time and frequency domain analysis of HRV on 24‐hour ambulatory ECG recordings was performed before and after ablation. Root mean square of differences of consecutive N‐N intervals (rMSSD), percentage of difference between consecutive N‐N intervals >50 ms (pNN50), and high frequency (HF) component were measured to examine the effects on parasympathetic nerve activity. In group AT, rMSSD, pNN50, and HF decreased significantly after ablation, while they remained unchanged in group Paf and group VT. These observations suggest that parasympathetic denervation after ablation was limited to group AT, and depended on the site of energy delivery along the tricuspid or mitral valve as opposed to atrial or ventricular muscle.

Effect of Left Atrial-Coronary Sinus Musculature Connections on the Coronary Sinus Activation Pattern via Retrograde Conduction in Patients with WPW Syndrome

AbstractBackground: Double potential (DP) activation patterns observed in coronary sinus (CS) electrograms recorded during left lateral atrial pacing, were explained by an initial low-frequency left atrial (LA) activation potential and secondary high-frequency CS musculature activation potential in canine hearts. Moreover, the connections between the LA and CS musculature vary greatly in size and location in the human heart. The purpose of this study was to investigate the relationship between the CS activation pattern during retrograde conduction via an accessory pathway (AP) and the location of left-sided APs.nMethods and Results: Fifty-one patients (31 males, mean age 48.6 years) who underwent radiofrequency catheter ablation of left-sided APs were divided into two groups according to the successful ablation site. The CS electrograms during retrograde AP conduction were classified into 3 types; single, fractionated, and DP activation patterns. A DP pattern was identified in 10 of 12 patients (83.3%) with posteroseptal to posterolateral APs, and in particular, 9 had a divergent sequence. Twenty-six of 39 patients (66.7%) with lateral to anterolateral APs, demonstrated a single pattern. The number of radiofrequency applications was significantly higher in patients with a DP pattern than in those with a single pattern (3.4 ± 3.3 vs. 7.8 ± 6.8, p < 0.01).nConclusion: Misleading information obtained when mapping for optimal ablation sites might result from DP patterns with a divergent sequence produced by discrete muscular connections between the LA and CS musculature. Ablation around left posterior APs may require meticulous observation of the CS activation patterns.

Electrophysiological Characteristics During Slow Pathway Ablation of Posterior Atrio ventricular Junctional Reentrant Tachycardia

The purpose of this study was to compare the electrophysiological characteristics of posterior and anterior atrioventricular junctional reentrant tachycardia (AVJRT) during radiofrequency (RF) catheter ablation of a slow pathway. Twenty‐four patients with common A VJRT, including 4 posterior (P) and 20 anterior AVJRT (A) were studied. We analyzed the retrograde atrial activation sequence of junctional rhythm and the presence of transient HA block during slow pathway ablation. When HA block developed, the AH interval before ablation and immediately after the end of energy delivery was measured. Successful ablation sites were divided into three groups; high (H), middle (M), and low (L) from the His bundle to the floor of the coronary sinus orifice. The results were: (1) the number of successful ablation sites were H 0, M 1, L 3 in P and H 1, M 8, L 11 in A; (2) the HA interval during AVJRT in P was longer than that in A (109 ± 48 ms vs 43 ± 6 ms, P < 0.01); (3) the retrograde atrial activation sequence during Junctional rhythm was strictly concordant with that during AVJRT in both groups, but HA block developed during slow pathway ablation more often in P than in A (100% vs 30%, P < 0.01); and (4) The AH interval did not lengthen after HA block developed in P. These data suggest that another pathway does exist from the A V node to the atrium in addition to anterograde fast pathway and slow pathway, and that this pathway is used as the retrograde limb of P.