Giorgio Corbucci

Direct His bundle pacing preserves coronary perfusion compared with right ventricular apical pacing: a prospective, cross-over mid-term study

AIMSnThe His bundle is regarded as the most physiological site for ventricular pacing, in that it avoids the adverse effects of right ventricular apical pacing (RVAP). However, very few studies have compared the effects of direct His bundle pacing (DHBP) and RVAP. The aim of our study was the intra-patient comparison of myocardial perfusion corresponding to these two different pacing techniques, as perfusion expresses local workload and is related to long-term outcome.nnnMETHODS AND RESULTSnTwelve consecutive patients with standard pacemaker indication (9 male, 74 +/- 9 years) entered the study. Pacing leads were implanted in the right ventricular apex and directly in the His bundle, and were connected to different ports of the pacemaker. All patients first underwent 3 months of DHBP, followed by 3 months of RVAP. At the end of each 3-month period, myocardial perfusion was measured at rest using scintigraphy with Tc99m-SestaMIBI. The average values of perfusion were evaluated on a 20-segment basis. All patients also underwent clinical evaluation, echocardiography, and tissue Doppler imaging (TDI), to measure dyssynchrony, and a blood sample was taken for brain natriuretic peptide (BNP) assay. The perfusion score during DHBP pacing was significantly better than during RVAP (0.44 +/- 0.5 vs. 0.71 +/- 0.53, respectively; P = 0.011). None of the patients showed lower perfusion during DHBP than during RVAP. We found no significant difference in NYHA class, ventricular volumes, ejection fraction, or plasmatic BNP between DHBP and RVAP. However, mitral regurgitation (0.26 +/- 0.21 vs. 0.37 +/- 0.25; P < 0.001) and dyssynchrony (13.75 +/- 4.28 vs. 22.02 +/- 8.44; P = 0.008) were significantly less during DHBP than during RVAP.nnnCONCLUSIONnDirect His bundle pacing is superior to RVAP in preserving the physiologic distribution of myocardial blood flow and reducing mitral regurgitation and left ventricular dyssynchrony.

Ventricular-arterial coupling in patients with heart failure treated with cardiac resynchronization therapy: may we predict the long-term clinical response?

OBJECTIVEnTo evaluate the effects of cardiac resynchronization therapy (CRT) on ventricular-arterial coupling (VAC) in patients with refractory congestive heart failure (HF), left bundle brunch block, and sinus rhythm.nnnBACKGROUNDnThe ratio between arterial elastance (Ea) and left ventricular end-systolic elastance (Ees), the so-called VAC, defines the efficiency of the myocardium in pumping blood.nnnMETHODSnSeventy-eight patients were studied with echocardiography before CRT, and 1 year later. End-systolic elastance was calculated according to the method of Chen. Arterial elastance (ratio of the systolic pressure to the stroke volume), end-systolic volume (ESV), and quality of life (QoL) (Minnesota Living with Heart Failure Questionnaire) were assessed at the baseline and after 1 year. Patients with a reduction>15% of ESV or a decrease>33% in QoL score were considered responders to CRT.nnnRESULTSnQRS duration and interventricular delay were significantly reduced with CRT compared with baseline (156+/-2 vs. 195+/-3 ms, P<0.001; and 25+/-2 vs. 55+/-3 ms, P<0.001, respectively). Arterial elastance/Ees decreased significantly on CRT (2.47+/-1.48 vs. 1.41+/-0.87, P<0.0001). The lowering of Ea/Ees was congruent to a decrease in intraventricular delay (83.1+/-55.7 vs. 28.4+/-49.5 ms, P<0.0001) and an increase in ejection fraction (26+/-6.3 vs. 36.9+/-8.0%, P<0.0001). Responders to CRT were 74 and 71% of the overall patient population, considering as endpoint QoL or ESV, respectively. The analysis of VAC showed a baseline cut-off value of 2, above which 88% and 69% of patients responded to CRT, considering as endpoint QoL or ESV, respectively.nnnCONCLUSIONSnThe non-invasive assessment of VAC may be proposed as an immediate, easy, and optimal tool for quantifying the effect of CRT in patients with HF.

Is pretreatment with ibutilide useful for atrial fibrillation cardioversion when combined with biphasic shock

Objective Cardioversion of atrial fibrillation by means of a monophasic transthoracic shock is facilitated by pretreatment with ibutilide. The aim of this study was to randomly and prospectively compare the energy requirements of transthoracic biphasic cardioversion of atrial fibrillation with and without ibutilide pretreatment. Methods Fifty patients were enrolled and randomized into two groups: immediate cardioversion with biphasic shock (group 1) or ibutilide pretreatment followed by cardioversion with biphasic shock (group 2). In group 2, ibutilide was administered intravenously in 10 min at a dose of 0.01 mg/kg. A pause of 10 min was observed before the patients underwent cardioversion. Results All patients of both groups were successfully cardioverted (100%). Energy and number of shocks were significantly lower in group 2 than in group 1 (P < 0.02). Eleven of 25 patients (44%) in group 1 and 15 of 23 patients (65%) in group 2 were cardioverted at the first attempt with 50 J. The number of patients cardioverted at the first attempt with 50 J was significantly higher in group 2 than in group 1 (P = 0.018). Conclusions Although not essential for a successful outcome, pretreatment with ibutilide can lower energy requirements in transthoracic biphasic cardioversion.

Prevalence of conduction delay of the right atrium in patients with SSS: Implications for pacing site selection

Objectives To evaluate the prevalence of severe right atrial conduction delay in patients with sinus node dysfunction (SND) and atrial fibrillation (AF) and the effects of pacing in the right atrial appendage (RAA) and in the inter-atrial septum (IAS). Methods Forty-two patients (15 male, 72 ± 7 years) underwent electrophysiologic study to measure the difference between the conduction time from RAA to coronary sinus ostium during stimulation at 600 ms and after extrastimulus (ΔCTos). Patients were classified as group A if ΔCTos > 60 ms and group B if < 60 ms. Each Group was randomized to RAA/IAS pacing and algorithms ON/OFF. Results Fifteen patients (36%, group A) had ΔCTos = 76 ± 11 ms and 27 patients (64%, group B) had ΔCTos = 36 ± 20 ms. Twenty-two patients were paced at the RAA and 20 at the IAS. During the study, no AF recurrences were reported in 11 of 42 (26%) patients, independently of RAA or IAS pacing. Patients from group A and RAA pacing had 0.79 ± 0.81 episodes of AF/day during DDD, which increased to 1.52 ± 1.41 episodes of AF/day during DDDR + Alg (P = 0.046). Those with IAS pacing had 0.5 ± 0.24 episodes of AF/day during DDD, which decreased to 0.06 ± 0.08 episodes of AF/day during DDDR + Alg (P = 0.06). In group B, no differences were reported between pacing sites and pacing modes. Conclusions Severe right atrial conduction delay is present in one-third of patients with SND and AF: continuous pacing at the IAS is superior to RAA for AF recurrences. In patients without severe conduction delay, no differences between pacing site or mode were observed.

Long-term follow-up of patients paced in VDD mode for advanced atrioventricular block: a pilot study.

Objective The aim of this pilot study was to estimate the survival trend of patients implanted with VDD pacemakers, and to compare it with the survival curve of the general population of the same region. Methods Ninety-seven patients (65 male, mean age 78 ± 6 years) with advanced atrioventricular block referred to our institution were implanted with single-lead VDD pacemakers. All patients were stimulated at the right ventricular apex. At each follow-up visit, a clinical examination was performed and telemetric data collected. In case of death, the family was contacted to record the cause of death. Data on the survival probability of the general population in the Marche Region were obtained from the Italian Institute of Statistics (ISTAT). Results During the follow-up (mean 7 ± 6 years), 17 patients (17.5%) died and eight patients (8.2%) developed atrial fibrillation. Atrioventricular synchrony was 97 ± 3% in the overall patient population, excluding patients with atrial fibrillation. Only one patient was upgraded to DDD pacing owing to symptomatic loss of atrial sensing; after the upgrading procedure symptoms disappeared. During the follow-up period, 19 pacemakers were replaced for end of life of the battery. Patients who died during follow-up were aged 80 ± 7 years at implantation and 85 ± 6 years at death. The comparison between the trend line simulating the patient survival probability of the studied VDD population, and the survival probability of males in the Marche Region did not show any significant difference. Conclusions In patients chronically paced with a single-lead VDD system, survival probability seems to be similar to that of the general population.