Yasutsugu Nagamoto

Bipolar electrogram amplitudes in the left atrium are related to local conduction velocity in patients with atrial fibrillation

AIMS It is unclear how the amplitude of bipolar electrogram relates to the local conduction velocity (CV) in patients with atrial fibrillation (AF). For 50 AF patients (paroxysmal/persistent AF: 40/10 patients), contact bipolar voltage maps of the left atrium (LA) were constructed during sinus rhythm using EnSite version 6.0J in a point-by-point recording fashion. Patients were divided into Groups A (n = 16), B (n = 19), and C (n = 15) according to the level of the lowest electrogram amplitudes: <0.5, 0.5-0.75, and 0.75-1.0 mV, respectively. Low-voltage zone (LVZ) was defined separately for these groups as a bipolar electrogram amplitude of <0.5, 0.5-0.75, and 0.75-1.0 mV, respectively. The local CV through the LVZ and non-LVZ was calculated along the direction of local activation within each zone for all groups. METHODS AND RESULTS Low-voltage zone was consistently found at the septal, anterior, and posterior LA in all groups. In Group A, CV through the LVZ was significantly slower compared with the non-LVZ (0.8 +/- 0.5 vs. 1.4 +/- 0.6 m/s, P = 0.004), but those through the LVZ and non-LVZ were similar in Group B (1.2 +/- 0.5 vs. 1.3 +/- 0.5 m/s, P = 0.07) and Group C (1.5 +/- 0.5 vs. 1.4 +/- 0.6 m/s, P = 0.79). The percentage of points showing fractionated or double potentials in the LVZ was significantly more in Group A (76/293 points, 26%) than in Group B (11/185 points, 6%), and Group C (7/135 points, 5%) (P < 0.0001 and P < 0.0001, respectively). CONCLUSION There was a significant slowing of local conduction in the LVZ defined as <0.5 mV and was frequently associated with fractionated or double potentials in patients with AF.

Characterization of non-pulmonary vein foci with an EnSite array in patients with paroxysmal atrial fibrillation

AIMS Non-pulmonary vein (PV) foci are sometimes difficult to identify and eliminate. The EnSite array (EA) reveals the detailed beat-to-beat virtual activation. This study aimed to characterize non-PV foci using the EA. METHODS AND RESULTS Sixty-five patients with paroxysmal atrial fibrillation (AF) were included. All had ectopy initiating AF and/or focal atrial tachycardia analysed using the EA. All patients underwent PV isolation (PVI) and additional ablation of non-PV foci if present. The EA revealed 59 PV foci in 48 patients (Group P) and 19 non-PV foci in 17 patients (Group N). In Group N, 12 patients (71%) also had 17 PV foci. The non-PV foci were frequently distributed in the left atrial (LA) roof (n = 5) and superior vena cava (n = 5). Pulmonary vein isolation during on-going AF terminated AF in 34 of 37 in Group P (92%) and 4 of 14 in Group N (29%) patients (P < 0.0001). All non-PV foci were eliminated by an EA-guided ablation. During a 23 ± 10 month follow-up, 11 patients (17%) had AF recurrences, mainly due to LA-PV reconnection. CONCLUSION Non-PV foci are prevalent in the LA roof and SVC sites, but can originate from other sites as well. When non-PV foci are observed, PVI may be insufficient and should be supplemented with non-PV foci ablation.

Chronic cardiac resynchronization therapy reverses cardiac remodelling and improves invasive haemodynamics of patients with severe heart failure on optimal medical treatment

AIMS The aim of this study was to assess chronic invasive haemodynamic effects of cardiac resynchronization therapy (CRT) in patients with severe heart failure. METHODS AND RESULTS Seventeen patients with New York Heart Association (NYHA) class III or IV and QRS duration >120 ms on optimal treatments underwent CRT. Haemodynamic data were obtained by cardiac catheterization before and 1 month after CRT. Clinical parameters and exercise tolerance were also evaluated. Chronic CRT improved haemodynamics significantly; mean pulmonary capillary wedge pressure decreased from 15.9 +/- 6.1 to 10.2 +/- 5.3 mmHg (P < 0.05), systolic pulmonary artery pressure decreased from 36.5 +/- 13.2 to 26.7 +/- 11.9 mmHg (P < 0.05), left ventricular end-diastolic pressure decreased from 15.6 +/- 7.2 to 10.5 +/- 7.3 mmHg (P < 0.05), end-diastolic volume decreased from 358.8 +/- 84.6 to 322.9 +/- 99.0 mL (P < 0.05), end-systolic volume decreased from 264.1 +/- 67.6 to 219.2 +/- 74.3 mL (P < 0.05), left ventricular ejection fraction increased from 25.4 +/- 6.2 to 33.1 +/- 4.9% (P < 0.05), and cardiac index increased from 1.9 +/- 0.4 to 2.2 +/- 0.5 L/min/m(2) (P < 0.05). Chronic CRT significantly improved functional capacity such as NYHA classification, 6 min walk distance, and peak oxygen uptake. CONCLUSION Chronic CRT improved not only symptoms and exercise tolerance but also invasive haemodynamics associated with reversed cardiac remodelling.

Characterization of bipolar electrograms during sinus rhythm for complex fractionated atrial electrograms recorded in patients with paroxysmal and persistent atrial fibrillation.

AIMS Complex fractionated atrial electrogram (CFAE) has been reported to relate to maintain atrial fibrillation (AF). The aims of this study were to investigate the relationship between CFAE and background conditions during sinus rhythm (SR). METHODS AND RESULTS Electroanatomical mapping using an EnSite Array was performed in 20 patients (paroxysmal AF:persistent AF = 16:4) who underwent pulmonary vein antrum isolation (PVAI). Contact bipolar electrograms were recorded before PVAI, during SR, and subsequently during induced AF. Peak-to-peak voltages and morphologies of the electrograms during SR were compared between sites with and without CFAE during AF. Among 1947 points obtained during SR, 974 (50%) were included in CFAE sites and 973 (50%) in non-CFAE sites. Electrogram amplitude during SR was higher at the CFAE sites than at the non-CFAE sites (2.4 +/- 1.7 vs. 1.9 +/- 1.9 mV; P < 0.0001), whereas fractionated or double electrograms were found in a similar range between the two areas (2 vs. 3%; P = 0.21). When analysed further in terms of AF termination by PVAI followed by confirmation of non-inducibility, the voltage of electrograms at the CFAE sites was lower (2.1 +/- 1.7 vs. 2.6 +/- 1.8 mV; P = 0.0001) and the morphology was more complex in patients without AF termination compared with those with AF termination. CONCLUSION Our results suggest that in paroxysmal and persistent AF with minimally damaged LA, the CFAE sites in patients with AF termination by PVAI alone represent healthy atrial tissue with rapid electrical activity in response to an AF driver located in the pulmonary vein. However, in patients without AF termination, they represent more damaged tissue responsible for maintaining AF.

Implantation of pacemaker for sick sinus syndrome in a patient with persistent left superior vena cava and absent right superior vena cava

Absent right superior vena cava with persistent left superior vena cava in normal situs is an exceedingly rare congenital anomaly. In such cases, pacemaker implantation (PMI) is very difficult or even impossible. We report the case of a patient with sick sinus syndrome in whom PMI was easily performed via the left superior vena cava by using a steerable stylet.