Biomedical subjects

Nicola Musilli

Publications and source records attributed to Nicola Musilli.

10 recordsLinked to original sources

PubMed2006

Effects of cardiac resynchronization therapy on the mechanisms underlying functional mitral regurgitation in congestive heart failure.

AIMS: Functional mitral regurgitation (FMR) improvement induced by cardiac resynchronization therapy (CRT) has been related to left ventricular (LV) remodeling reversal and contractility enhancement. The effects induced by the changes of LV synchronicity indexes on FMR severity have not been investigated. METHODS AND RESULTS: In 30 patients with CRT for heart failure (HF) and QRS>130 ms, LV function parameters, FMR severity as mitral jet regurgitation/left atrial area ratio (JA/LAA) and standard deviation (SD) of the time to the systolic peak velocity at 6-basal and mid-LV segments as asynchrony indexes were evaluated (echo/tissue Doppler) before and 6 months after implant. At follow-up, 15 patients resulted responders to LV reverse remodeling with > or =15% end-systolic volume (ESV) and LV systolic function improvement. Improvement of FMR with > or =15% JA/LAA reduction was observed in 19 patients, 7 were nonresponders to LV reverse remodeling. In patients with > or =15% JA/LAA reduction a significant decrease of LV asynchrony indexes was observed as compared to patients without > or =15% JA/LAA reduction in whom LV asynchrony indexes were increased. Reduction of LV mid-segmental asynchrony was the variable most strongly related to JA/LAA reduction (r(2)=0.697, P<0.01), with good agreement between observed and predicted values (only 1 patient outside the mean+/-2SD). CONCLUSION: These data reveal that CRT can reduce FMR irrespective to LV remodeling reversal; this effect is related to LV asynchrony reduction and further support CRT employment in patients with HF and FMR.

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PubMed2005

Evolution and prognostic significance of diastolic filling pattern in cardiac resynchronization therapy.

BACKGROUND: Cardiac resynchronization therapy (CRT) is an emerging treatment for heart failure patients with left bundle branch block; in these patients left ventricle filling pattern (LVFP) abnormalities are recognized as cause of symptoms and predictors of outcome. We investigated the effects of CRT on diastolic function and the prognostic value of LVFP in patients on CRT. METHODS: 65 patients treated with CRT were studied over a 12 months period. At baseline, according to defined echocardiographic criteria, restrictive LVFP (RFP) was present in 25 patients, whereas 40 patients showed no-RFP. RESULTS: After CRT, opposite changes occurred in the two groups. In no-RFP patients, early-to-atrial filling velocity ratio (E/A) increased from 0.8+/-0.3 to 1.0+/-0.6 (p=0.006) and E wave deceleration time (DT) decreased from 234+/-83 ms to 196+/-51 ms (p=0.028). In 13 RFP patients, E/A decreased from 2.2+/-0.9 to 0.8+/-0.5 and DT increased from 128+/-43 ms to 205+/-52 ms (both p<0.001), leading to reversal of RFP. In both groups, clinical, functional and echographic benefits were evident, with mortality rates of 5% (2/40) and 15% (2/13) respectively. The remaining patients showed persistence of RFP (E/A and DT unchanged), no improvement and a mortality rate of 42% (5/12) (p=0.005, versus no-RFP). CONCLUSIONS: CRT improves diastolic function, inducing also reversal of LVFP in a consistent number of RFP patients. The persistence of RFP after CRT is associated to an extremely poor prognosis.

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PubMed2005

Pacemaker selection: time for a rethinking of complex pacing systems?

Evidence from randomized trials indicates that the clinical benefits of dual-chamber (DDD) pacing are modest: (i) no significant differences exist between physiological pacing and single-chamber pacing in mortality and stroke; (ii) ventricular desynchronization resulting from chronic right-ventricular pacing in DDD mode, induces a significantly increased incidence of atrial fibrillation (AF) and heart failure hospitalizations; (iii) AF pacing prevention and therapy algorithms have shown a modest to minimal or absent efficacy; (iv) the widespread use of physiological pacemakers is not an economically attractive strategy. Thus, these data provide a reliable body of evidence on which to make more rationale clinical decisions for individual patients and policy decisions for health costs saving. The cheaper single-chamber AAI(R) or VVI(R) has been shown to satisfy both conditions in most cases of sinus node disease and AV block.

Atrial Fibrillation↗

PubMed2005

Echocardiographic examination of atrioventricular and interventricular delay optimization in cardiac resynchronization therapy.

In 21 patients implanted with a biventricular pacing device with programmable interventricular delay (VVd), the myocardial performance index (MPI) was evaluated during spontaneous sinus rhythm, simultaneous biventricular pacing, and sequential biventricular pacing at different VVds and atrioventricular delays (AVds). The AVd-VVd combination associated with the minimum MPI defined patient-tailored biventricular pacing. Simultaneous biventricular pacing significantly improved MPI compared with spontaneous sinus rhythm. An additional improvement was obtained by tailored biventricular pacing. The optimal AVds were significantly shorter during right ventricular preactivation than during left ventricular preactivation.

Acute Disease↗

PubMed2005

Rate stabilization by right ventricular apex or His bundle pacing in patients with atrial fibrillation.

AIMS: In patients with atrial fibrillation right ventricular pacing can block antegrade conduction at pacing intervals longer than the shortest spontaneous R-R interval, causing the stabilization of ventricular rhythm. In this study the effects of pacing at two sites were compared in order to evaluate the role of conduction times in determining the stabilization of ventricular rhythm. METHODS: In eight patients with permanent atrial fibrillation, the ventricular rate was recorded before and during pacing at the right ventricular apex and the His bundle with different cycle lengths. RESULTS: In all patients, we obtained a reduction in spontaneous QRS complexes with respect to those anticipated at pacing rates slightly above the spontaneous mean rate, and the ventricular rhythm stabilized at pacing intervals longer than the spontaneous shortest R-R intervals. Between pacing sites we did not observe any difference in the reduction in spontaneous beats and the cycle stabilizing the rhythm. Moreover, simulation of the interaction between antegrade and retrograde impulses in a computer model confirmed that results obtained by pacing at the His bundle cannot be readily explained as a consequence of conduction delays. CONCLUSION: This study suggests that the lag introduced by the His-Purkinje conduction cannot explain, as proposed, the stabilization of ventricular rhythm observed in patients with atrial fibrillation and right ventricular pacing.

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PubMed2004

Atrial fibrillation and cardiac resynchronization therapy: the MASCOT study.

Atrial fibrillation (AF) and congestive heart failure (CHF) share several characteristics and often coexist in the same patient. Both are responsible for significant morbidity and mortality, are increasing in prevalence, and are major sources of health expenditure. The Management of Atrial fibrillation Suppression in AF-HF COmorbidity Therapy (MASCOT) study is a European, single-blind, prospective, controlled, multicentre, randomized clinical trial designed to examine whether adding the AF Suppression Algorithm to cardiac resynchronization therapy (CRT) improves the prognosis of patients with CHF. The patients will be randomly assigned to a CRT-only group, with the AF Suppression algorithm programmed OFF (control group), versus a CRT+AF Suppression group, with the algorithm programmed ON (treatment group). The primary study endpoint is development of permanent AF, and secondary endpoints are safety of the AF Suppression algorithm, and evolution of multiple clinical variables over 24 months of follow-up. CRT combined with a refined atrial tachyarrhythmia prevention pacing algorithm may represent a major advance in the management of AF and CHF by electrical stimulation.

Algorithms↗

PubMed2004

A perspective on atrioventricular delay optimization in patients with a dual chamber pacemaker.

Atrioventricular delay (AVD) is critical in patients with DDD pacemakers (PM). Echo/Doppler evaluation of AVD providing the longest left ventricular filling time (FT) or the highest cardiac output (CO) is used for AVD optimization. Recently myocardial performance index (MPI) has been shown to improve by optimizing AVD. The aim was to compare the CO, FT, MPI derived optimal AVD, and to analyze systolic and diastolic performance at every optimal AVD. Twenty-five patients, 16 men 68 +/- 11 years, ejection fraction >or= 50%, with a DDD PM for third-degree AV block, without other major cardiomyopathies, underwent echo/Doppler AVD optimization. CO, FT, and MPI derived optimal AVDs were identified as the AVDs providing the highest CO, the longest FT, and the minimum MPI, respectively. Isovolumic contraction and relaxation time (ICT, IRT), ejection time (ET), ICT/ET, and IRT/ET ratios were also evaluated at every optimal AVD. CO, FT, and MPI derived optimal AVDs were significantly different (148 +/- 36 ms, 116 +/- 34 ms, and 127 +/- 33 ms, respectively). ICT/ET was similar at CO, FT, and MPI derived optimal AVD (0.22 +/- 0.10, 0.23 +/- 0.11, and 0.21 +/- 0.10, respectively). IRT/ET ratio was similar at FT and MPI derived optimal AVDs (0.34 +/- 0.15 and 0.33 +/- 0.15, respectively) and significantly shorter (P < 0.02) than at CO derived optimal AVD (0.40 +/- 0.15). Different methods indicate different optimal AVDs. However analysis of systolic and diastolic performance shows that different AVDs result in similar systolic or diastolic performance. At MPI optimized AVD, a high CO combined with the most advantageous conditions of both isovolumic contraction and relaxation phases is achieved.

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PubMed2004

Atrial septal pacing: a new approach to prevent atrial fibrillation.

Atrial pacing may prevent the onset of atrial fibrillation (AF) because of: (1) prevention of the relative bradycardia that triggers paroxysmal AF; (2) prevention of the bradycardia induced dispersion of refractoriness; (3)suppression or reduction of premature atrial contractions that initiate reentry and predispose to AF; (4) preservation of AV synchrony, which might prevent switch induced changes in atrial repolarization predisposing to AF. Atrial pacing locations that decrease atrial activation and dispersion of refractoriness may be preferable in patients with a history of AF. Two different interatrial septum sites have been proposed: the Bachmann's bundle and the coronary sinus ostium. The results of two prospective randomized studies indicate that septal pacing, when compared to the traditional right atrial appendage pacing, significantly reduces : (1) paroxysmal AF recurrences and burden; and (2) progression to chronic AF.

Animals↗

PubMed2003

Prevention of paroxysmal atrial fibrillation in patients with sinus bradycardia: role of right atrial linear ablation and pacing site.

INTRODUCTION: Right atrial linear lesions (RALL), either alone or in combination with antiarrhythmic drug therapy, may modify the substrate for maintenance of atrial fibrillation (AF). The aim of this prospective randomized study was to determine whether RALL provides additional benefit to right atrial appendage pacing (RAAP) and/or interatrial septum pacing (IASP) and drug therapy in patients with symptomatic paroxysmal AF and sinus bradycardia requiring permanent atrial pacing. METHODS AND RESULTS: Sixty-four patients (33 men and 31 women, mean age 73 +/- 10 years) completed the 6-month follow-up. Patients were randomized to either RALL (n = 33) or non-right atrial linear lesions (NRALL), and then to either IASP (n = 32) or RAAP (n = 32). Fifteen RALL patients were paced at the IAS and 18 at the RAA. Seventeen NRALL patients were paced at the IAS and 14 at the RAA. No statistical difference was observed with regard to the mean atrial tachyarrhythmia (AT) burden between NRALL (84 +/- 169 min/day) and RALL patients (202 +/- 219 min/day). Mean AT burden was significantly lower in the IASP group (70 +/- 150 min/day) than in RAAP group (219 +/- 317 min/day; P < 0.016). In the RALL group, the mean AT burden was 99 +/- 180 min/day in the IASP patients and 288 +/- 372 min/day in the RAAP patients (P < 0.046). In the NRALL group, no statistical difference in the mean AT burden was observed between IASP patients (46 +/- 117 min/day) and RAAP patients (130 +/- 211 min/day). CONCLUSION: The results of the present study indicate that RALL did not provide any additional therapeutic benefit to combined antiarrhythmic drug therapy and septal or nonseptal atrial pacing in patients with sinus bradycardia and paroxysmal AF.

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PubMed2002

Interatrial septum pacing avoids the adverse effect of interatrial delay in biventricular pacing: an echo-Doppler evaluation.

AIMS: Biventricular pacing (BVP) can improve haemodynamics in patients with dilated cardiomyopathy (DCM) and left bundle branch block by reducing interventricular delay (IVD). Since in DCM interatrial delay (IAD) and IVD frequently coexist, the aim of this study was to test the hypothesis that IVD reduction associated with IAD produces an imbalance between the programmed right atrioventricular (AV) delay and the effective AV delay on the left, and that interatrial septum pacing (IASP) combined with BVP overcomes this adverse effect. METHODS AND RESULTS: IAD, IVD, left and right mechanical atrioventricular delay (L-RMAVD) were measured by echo-Doppler in 29 patients with BVP: 17 patients (Group A) had the atrial lead in the right atrial appendage, 12 patients (Group B) who experienced paroxysmal atrial fibrillation had the atrial lead on the interatrial septum. In Group A, LMAVD was significantly shorter than RMAVD (172 +/- 24 vs 207 +/- 24 ms, P<0.002), IAD was significantly longer than IVD (52 +/- 24 vs 21 +/- 18 ms, P<0.0001). In Group B, no differences were observed between LMAVD and RMAVD (187 +/- 32 vs 185 +/- 28 ms, NS), and between IAD and IVD (11 +/- 12 vs 13 +/- 16 ms, NS). CONCLUSIONS: IAD produces different left and right atrioventricular sequences in BVP. IASP combined with BVP, by resynchronizing both atria and ventricles, is able to avoid this adverse effect.

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