Acute Left Ventricular Dyssynchrony Improvement Predicts Long-Term Benefit from Cardiac Resynchronization Therapy

Study Objective: To evaluate the relationship between acute response to cardiac resynchronization therapy (CRT) and long-term clinical outcome in patients with drug refractory heart failure.
Methods and Results: In 28 patients undergoing CRT implant, left ventricular (LV) dyssynchrony was evaluated by tissue Doppler imaging (TDI)-derived longitudinal strain by mean of septum-lateral basal asynchrony index (S-Li) and basal delayed longitudinal contraction (DLC). TDI measurements were made before, and 30 minutes and 1 year after implant. Baseline and 1-year follow-up New York Heart Association (NYHA) functional class, 6-minute walking test (6-MWT) distance, and quality of life (QoL) score were measured. Responders (n = 22) were defined by a ≥ 1 decrease in NYHA functional class and 6-MWT ≥25% at 1 year. At baseline, no differences were observed between responders and nonresponders in clinical and echocardiographic measurements. LV dyssynchrony acutely recovered only in responders 30 minutes after implantation, with a significant reduction in S-Li and DLC. Moreover, the percent decreases in S-Li and DLC were highly correlated with those observed in NYHA class (r = 0.70, and r = 0.81, respectively, P < 0.001), 6-MWT (r = 0.59, and r = 0.57, respectively, P < 0.001 and P < 0.01), and QoL score (r = 0.71, and r = 0.83, respectively, p < 0.001) at 1-year follow-up.
Conclusions: Acute recovery of LV intraventricular dyssynchrony is a major discriminator between responders and nonresponders to CRT, which strongly correlates with a favorable long-term clinical outcome.     

Alternating Left and Right Bundle Branch Block Aberration of Atrial Extrasystoles in Bigeminal Rhythm

We report two cases of atrial extrasystolic bigeminy manifesting with alternating right and left bundle branch block aberration. The manifestation is explained on the basis of cycle-dependent variations of the bundle branch refractory period with alternate resetting of bundle branch refractoriness.     

Right Atrial Appendage Versus Bachmann's Bundle Stimulation: A Two-Year Comparative Study of Electrical Parameters in Myotonic Dystrophy Type-1 Patients

Aim: We performed a two-year follow-up comparative study of long-term electrical parameters between the right atrial appendage (RAA) and Bachmann's Bundle (BB) stimulation in myotonic dystrophy type 1 (MD1) patients.
Methods: Twenty-five MD1 patients (18 men; age: 54 ± 13 years) with no difference in the electrical parameters between the RAA site and the BB region at implantation were randomized into two groups: in group I (13 patients; age: 52 ± 14 years; four women) the atrial lead was placed in the RAA and in group II (12 patients, age: 56 ± 12 years, three women) the lead was placed in the BB region. Measurements of electrical parameters were recorded at follow-up intervals of 6 weeks and then 12 and 24 months postimplant.
Results: There was no statistically significant different in P-wave amplitude, pacing threshold, and impedance values between the two groups at 6 weeks. At 24 months follow-up, the intrinsic P-wave amplitude was 2.05 ± 1.45 mV in the RAA group versus 3.28 ± 1.09 mV in the BB group (P < 0.05); the pacing threshold was 1.85 ± 1.8 V in the RAA group versus 0.50 ± 0.39 V in the BB group (P = 0.03); there were no differences in the atrial impedance between the two groups during the follow-up period.
Conclusions: In a direct two-year follow-up comparison between the RAA and BB atrial pacing sites, we showed a statistically significant increased pacing threshold and decreased intrinsic P-wave amplitude during RAA stimulation in MD1 patients.     

Right atrial preference pacing algorithm in the prevention of paroxysmal atrial fibrillation in myotonic dystrophy type 1 patients: a long term follow-up study

Atrial Preference Pacing (APP) is a pacemaker (PM) algorithm that works by increasing the atrial pacing rate to achieve continuous suppression of a spontaneous atrial rhythm and prevent supraventricular tachyarrhythmias. We have previously shown that atrial preference pacing may significantly reduce the number and the duration of AF episodes in myotonic dystrophy type 1 (DM1) patients who are paced for standard indications.However, the role that APP therapies play in the prevention of AF in a long-term period remains still unclear. Aim of the present prospective study was to evaluate whether this beneficial effect is maintained for 24-months follow-up period.To this aim, 50 patients with Myotonic Dystrophy type 1 who underwent dual-chamber PM implantation for first- and second- degree atrioventricular block, were consecutively enrolled and followed for 2 years. One month later the stabilization period, after the implantation, they were randomized to APP algorithm programmed OFF or ON for 6 months each, using a cross-over design, and remained in the same program for the second year. The results showed that while the number of AF episodes during active treatment (APP ON phases) was lower than that registered during no treatment (APP OFF phases), no statistically significant difference was found in AF episodes duration between the two phases. Furthermore, during the APP OFF and APP ON phases, the percentage of atrial pacing was 0 and 99%, respectively, while the percentage of ventricular pacing did not show differences statistically significant (11 vs. 9%, P = 0.2). Atrial premature beats were significantly higher during APP OFF phases than during APP ON phases. Lead parameters remained stable over time and there were no lead-related complications. Based on these 24-months follow-up data, we can conclude that, in DM1 patients who underwent dual-chamber PM implantation, APP is an efficacy algorithm for preventing paroxysmal AF even in long term periods.Key words: myotonic dystrophy, atrial preference pacing, atrial fibrillation     

META-ANALYSIS OF ALCOHOL INTAKE IN RELATION TO RISK OF LIVER CIRRHOSIS

The heterogeneity in the results of observational studies thatinvestigated the association between alcohol consumption andrisk of liver cirrhosis was ana]ysed by means of a meta-analysisthat included 15 articles published from 1978 to 1997. Relativerisks associated with low levels of alcohol intake (25 g/day)ranged from 1.5 [95% confidence interval (CI): 1 4–1.5]for a linear model fitting the results of the six studies performedin Mediterranean areas, to 3.6 (95% CI 3.1–4.3) for aquadratic model fitting the results of the nine studies performedin other areas. A strong indication of heterogeneity was observedwhen combining all studies. Quadratic term of alcohol intake,quality of the study and area in which the study was performedexplained most of this heterogeneity. Efforts should be madeto explain the strong heterogeneity in the trend estimates.Reproducible methods to collect relevant and valid informationon alcohol intake should be developed and the role of drinkingpatterns and viral and nutritional factors in modifying theeffect of alcohol on the risk of liver cirrhosis should be investigated.     

Ropivacaine in paediatric surgery: preliminary results

In a double blind study 40 patients, aged 1–9 years, undergoing elective minor surgery were examined and randomly divided in two groups (20 children each). After light general anaesthesia Group 1 received caudal injection of bupivacaine 0.25% 2 mg·kg^?1 while Group 2 received 0.2% ropivacaine 2 mg·kg^?1. No differences were observed in demographic data, HR, BP and duration of surgery; the onset time of anaesthesia was 12 min and 9 min in Group 1 and 2 respectively. Ten patients in Group 1 received paracetamol in the first 24 h after surgery while only two children in Group 2 needed analgesic; even the duration of analgesia in the patients requiring paracetamol was superior in group 2 (520 min vs 253 min). No motor block was apparent at awakening in either group and no side effect was noticed. In conclusion ropivacaine seems to be an effective and safe drug in paediatric regional anaesthesia.     

Left Ventricular Functional Recovery During Cardiac Resynchronization Therapy:

Cardiac resynchronization therapy (CRT) improves myocardial performance in patients with heart failure (HF) and left bundle-branch block (LBBB). Tissue Doppler echocardiography (TDE) has already been used to guide the selection of candidates for CRT. The objective of this study is to correlate the effects of CRT on left ventricular (LV) systolic function with wall motion synchrony assessed by TDE. High frame TDE data were obtained in 15 patients (mean age = 68.9 years, 11 men) with LBBB (QRS = 163 ± 13 ms) to derive temporal intraventricular horizontal asynchrony indexes, expressed as the time difference at the onset of shortening between the septum and the lateral (S-L) and antero-inferior (A-I) walls, and measure the amount of delayed longitudinal contraction (DLC) within the LV. All measurements were made at baseline, 24 hours after implantation, and at 1 year of follow-up. The results show that LV ejection fraction (EF) increased from 25 ± 6.2% at baseline to 36.9 ± 7.9% at 1 year, and was strongly related to DLC, expressed either by time duration (DLCd, r =−0.51; P < 0.0001) or percent of the basal segments (%DLC, r =−0.50; P < 0.001). New York Heart Association functional class, which decreased from 3.6 ± 0.5 to 2.3 ± 0.8, was correlated with %DLC (r = 0.50) and DLCd (r = 0.48, P < 0.001). Weaker correlations were found between LVEF and S-Li (r =−0.40) and between NYHA and S-Li (r = 0.40). It is concluded that DLC was the best among intraventricular asynchrony indexes in predicting increases in LVEF after CRT. DLC may be useful to identify responders to CRT.     

Radiographic Assessment of Atrial Dipole Position in Single Pass Lead VDD and DDD Pacing

Atrial electrode position was determined by radiographic analysis in 160 patients paced in single-lead VDD for second- or third-degree A-V block, implanted > 1 year with Phymos single pass leads and Phymos 3D pacemakers. The pacing lead features an atrial dipole with a 30-mm electrode interspace. In 44% of patients, the upper atrial electrode was positioned within a band of 20 mm centered at the level of the superior vena caval insertion (junctional area) and was in the inferior vena cava or in the atrium in 35% and 21 % of cases, respectively. In spite of these different dipole locations, all patients had stable atrium-driven pacing at routine follow-up visits. With the electrode in the junctional area, unipolar stimulation of up to 5 V for 1 ms resulted in stable atrial capture in 63% and 59% of the patients in supine and upright positions, respectively. With the electrode in the atrium, corresponding success rates were 45% and 54%. In the atrium, however, the prevalence of diaphragmatic stimulation was significantly lower than at the junction (10% vs 42% in supine position; 21 % vs 47% upright). Though atrial sensing function proved adequate in a wide range of positions, these results suggest that the Phymos lead atrial dipole should be positioned within the atrium, as close as possible to the atrial wall, to maximize the number of VDD patients who might benefit from single-lead DDD pacing.     

Remote Navigation and Ablation of Atrial Fibrillation

We have developed a new approach based on remote navigation and ablation by a magnetic catheter in a large number of patients with paroxysmal, persistent, or permanent atrial fibrillation. The operator sits in a separate control room, away from the X-ray beam and the patient's body. A 4 mm magnetic catheter is integrated with a newly developed electroanatomical mapping system. The catheter is moved by a joystick that allows to and fro movement inside the left atrium. Magnetic field vectors for each navigation target are stored and, if necessary, they are reapplied at any time while the magnetic catheter is navigated automatically. Remote circumferential pulmonary vein ablation is performed with a target temperature of 65°C and a power limit of 50 W. Navigation and ablation targets can be safely and successfully achieved in all patients in a relatively short period of time (usually in less than one hour). The manual approach is totally operator-dependent, while the remote one is not, but it mostly depends on a well-trained team. When combined with an accurate electroanatomical mapping system this remote technology allows not only to optimize contact and stability with tissue, but also to enable movement between preassigned intracardiac points automatically, either avoiding intervening tissue structures or moving at a defined rate across the surface of the intervening tissue. Finally, there is a significant shortening of radiation exposure time, relevant both for the unprotected patient and the operator.     

Effect of Secretin, Glucagon and Duodenal Acidification on Bombesin-induced Hypergastrinemia in Man

The action of duodenal acidification, of continuous I.V. infusion of secretin and glucagon and of a one bolus I.V. administration of secretin and glucagon at maximal doses on BBS-induced gastrin secretion has been studied in a group of 18 healthy subjects.
Continuous infusion of secretin and glucagon and the acidification of the duodenum did not alter significantly the levels of gastrin stimulated by BBS. Secretin and glucagon administered by a single I.V. bolus paritially inhibit the effect of BBS on gastrin levels.
On the basis of these results it is not possible to affirm or to exclude the possibility that BBS is a hormone physiologically present in man.