Biomedical subjects

Giorgio Corbucci

Publications and source records attributed to Giorgio Corbucci.

11 recordsLinked to original sources

PubMed2006

VDD pacemaker replacement is safe and reliable independently of the previously implanted lead: a prospective and controlled study.

UNLABELLED: Theoretically, replacement of a VDD device requires using a similar pacemaker to provide the best match between the filtering characteristics of the pacemaker and the atrial dipole of the lead. This study evaluated the performance of newly implanted Vitatron VDD pacemakers connected to dedicated leads and compared the results with those of the same Vitatron pacemakers used as replacement but connected to a variety of nondedicated leads. METHODS: 23 consecutive patients (15 M, 8 F, 78 +/- 6 years) in Group 1 underwent pacemaker replacement with a VDD(R) Saphir 3 (Vitatron BV, Arnhem, The Netherlands) device designed for an 8.6 mm atrial dipole. Atrial dipoles of the previously implanted leads ranged from 5 to 30 mm. Another 22 consecutive patients (14 M, 8 F, 80 +/- 7 years) in Group 2 received a Saphir 3 pacemaker with the related dedicated lead. RESULTS: P-wave amplitude measured by the same Pacing Sensing Analyzer (PSA) at the first implantation was 1.7 +/- 0.8 vs. 1.7 +/- 0.5 mV (P = NS) in groups 1 and 2 respectively. P-wave amplitudes measured at 1 month follow-up after replacement in Group 1 and at 1 month follow-up after implantation in Group 2 were 0.69 +/- 0.5 vs. 0.85 +/- 0.3 mV (P = NS) respectively. The percentage of atrial sensing at the same follow-up was 97 +/- 3 vs. 95 +/- 5% (P = NS) in groups 1 and 2 respectively. CONCLUSIONS: Replacement of VDD pacemakers with the Saphir 3 model designed for a short dipole is safe and reliable when used in combination with previously implanted nondedicated leads.

Aged↗

PubMed2006

The risk profile for obstructive sleep apnea does not affect the recurrence of atrial fibrillation.

BACKGROUND: Obstructive sleep apnea (OSA) has been linked to increased prevalence and recurrence of atrial fibrillation (AF). We hypothesized that OSA may aggravate AF in patients with pacemakers implanted for sinus bradycardia who had documented paroxysmal AF. METHODS: Seventy-two patients (36 M, aged 77 +/- 6 years) completed the study. All patients received a dual-chamber pacemaker equipped with diagnostic and preventive functions for AF. OSA was diagnosed with the Berlin Questionnaire, which is validated to identify patients with OSA. Four-month continuous pacemaker recordings were collected for all patients. RESULTS: OSA was diagnosed in 28% of patients. Patients at high risk for OSA (HR group) and patients at low risk for OSA (LR group) were equivalent for gender, age, and body mass index. The rate of hypertension was higher in HR than in LR group (90% vs 44%, P < 0.01). The prevalence of paroxysmal AF during the study period was similar in HR and LR group (53% vs 44%, P = NS). Overall number of AF episodes per month was not significantly different between HR and LR group (7 +/- 13 vs 36 +/- 122, P = NS). Similarly, AF burden (AF%) was not significantly different between HR and LR group (0.3 +/- 0.6 vs 2.0 +/- 4.8, P = NS). Circadian distribution of AF episodes was similar in both groups. CONCLUSION: Long-term pacemaker recording of AF recurrence, AF burden, and its circadian distribution is similar in patients with paroxysmal AF at high risk for OSA and those at low risk for OSA.

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PubMed2006

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.

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PubMed2005

The fusion band in V1: a simple ECG guide to optimal resynchronization? An echocardiographic case report.

BACKGROUND: Patients with left bundle branch block have a preserved right bundle branch conduction and the efficacy of left ventricular pacing could be explained with the fusion between artificial pulse delivered in the left lateral wall and the spontaneous right ventricular activation. Moreover, the efficacy of left ventricular pacing could be enhanced with an optimal timing between the spontaneous right ventricular activation and the left ventricular pulse. CASE PRESENTATION: We evaluated a patient (male, 47 yrs) with surgically corrected mitral regurgitation, sinus rhythm and left bundle branch block, heart failure (NYHA class III) despite medical therapy and low ejection fraction (25%): he was implanted with a biventricular device. We programmed ventricular pacing only through the left ventricular lead. We defined what we called electrocardiographic "fusion band" as follow: programming OFF the stimulator, we recorded the native electrocardiogram and measured, through the device, the intrinsic atrioventricular interval. Then, atrioventricular interval was progressively shortened by steps of 20 ms down to 100 ms. Twelve leads electrocardiogram was recorded at each step. The fusion band is the range of AV intervals at which surface electrocardiogram (mainly in V1 lead) presents an intermediate morphology between the native left bundle branch block (upper limit of the band) and the fully paced right bundle branch block (lower limit). The patient underwent echocardiographic examination at each atrioventricular interval chosen inside the fusion band. The following parameters were evaluated: ejection fraction, diastolic filling time, E wave deceleration time, aortic velocity time integral and myocardial performance index. All the echocardiographic parameters showed an improvement inside the fusion band, with a "plateau" behaviour. As the fusion band in this patient ranged from an atrioventricular delay of 200 ms to an atrioventricular delay of 120 ms, we chose an intermediate atrioventricular delay of 160 ms, presuming that this might guarantee the persistence of fusion even during any possible physiological (autonomic, effort) atrioventricular conduction variation. CONCLUSION: In this heart failure patient with left bundle branch block, tailoring of the atrioventricular interval resynchronized myocardial contraction with left ventricular pacing alone, utilizing a sensed right atrial activity and the surface electrocardiographic pattern.

Bundle-Branch Block↗

PubMed2005

Digital technology in cardiac pacing: methods for morphology analysis of sensed endocavitary signals.

UNLABELLED: Proper functioning of a pacemaker depends exclusively on the detection of intrinsic cardiac signals. Conventional devices merely establish the presence of an endocavitary potential, but do not evaluate it qualitatively. The recent incorporation of digital signal processing of sensed events in pacemaker permits diagnostic characterization heretofore impossible. METHODS: Digital processing was used in 268 cardiac cycles recorded from 5 patients during elective dual chamber pacemaker replacement, The signals were classified in real time by an external pacemaker equipped with hardware and software capabilities for this purpose. RESULTS: The parameters used for morphological analysis were the minimum value of the slope signal and the minimum value of the filtered signal. The discrimination of a true atrial signal from a far-field R wave was correct in every patient (p < 0.0001). CONCLUSION: Digital devices may monitor and classify every event continually, and dramatically increase device reliability and the amount of information that can be processed and stored.

Cardiac Pacing, Artificial↗

PubMed2005

DDD versus VVIR versus VVI mode in patients with indication to dual-chamber stimulation: a prospective, randomized, controlled, single-blind study.

BACKGROUND: The aim of this study was to compare VVI, VVIR and DDD modes in patients with indication to dual-chamber stimulation, depending on left ventricular function. METHODS: Two groups of patients were implanted with a DDD pacemaker: Group I with ejection fraction > 40% and Group II with ejection fraction < 40%. Patients with a history of atrial arrhythmia or retrograde conduction were excluded. At follow-up (1 month each) quality of life (QoL), patient preference and echo parameters were collected. At hospital discharge all patients were programmed in DDD for 1 month and then randomized to VVI or VVIR mode. At the end of the period in VVI or VVIR mode each patient underwent a control period in DDD and then was programmed in VVIR or VVI mode. RESULTS: Seventeen patients out of 23 preferred DDD mode and 6 did not perceive any subjective difference among DDD, VVI and VVIR modes (4/9 in Group I and 2/14 in Group II, p = 0.0017). QoL was significantly different between the two groups and at each follow-up showed the best values in DDD. The correlation between QoL and Tei index was 0.62 in Group I (p < 0.001) and 0.35 in Group II (p = 0.001). Neither ejection fraction nor fractional shortening showed any significant difference during the three phases of the study. CONCLUSIONS: Most patients preferred the DDD mode. The Tei index showed a good correlation with QoL and both QoL and Tei index significantly improved with DDD mode as compared to VVI and VVIR.

Adult↗

PubMed2004

Heart rate regularisation in patients with permanent atrial fibrillation implanted with a VVI(R) pacemaker.

UNLABELLED: Irregularity of ventricular cycles is a cause of haemodynamic impairment and symptoms in patients with atrial fibrillation (AF). AIM OF THE STUDY: Aim of the study was to determine the optimal pacing rate to stabilise ventricular cycle length at rest in patients with chronic AF, bradycardiac symptoms and VVI pacing. METHODS: The compensatory pause (CP) in AF, as defined by Langendorf, was used as a reference value in pacing the heart. The spontaneous mean heart rate (MHR) was assessed with the PM OFF. The CP was then calculated with the pacing rate programmed at 40 bpm. Four pacing rates were tested: rate of the CP (RCP), RCP + 5 bpm, RCP - 5 bpm and RCP - 10 bpm. RESULTS: RCP provided a good estimate of the MHR (r = 0.92). Pacing percentage (P%) was 24 +/- 15% at the pacing rate of RCP - 10 bpm, 39 +/- 19% at RCP - 5 bpm, 63 +/- 17% at RCP, and 79 +/- 19% at RCP + 5 bpm (p < 0.001). The corresponding HR modestly increased from 65 +/- 13 bpm to 66 +/- 13 bpm (p = NS), 68 +/- 13 bpm (p < 0.001) and 71 +/- 13 bpm (p < 0.001), respectively. CONCLUSION: The RCP estimates, during pacing, what the spontaneous MHR would be. Ventricular stimulation at the RCP causes a high P%, stabilising cardiac cycles with a modest increase in HR.

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PubMed2004

Methods for testing automatic mode switching in patients implanted with DDD(R) pacemakers.

The assessment of automatic mode switching (AMS) algorithms is impossible in vivo, due to a low chance of seeing the patient at the onset of a spontaneous episode of atrial fibrillation (AF). As the induction of AF to test AMS has clinical concerns, three alternative and non-invasive techniques may be proposed for this purpose: myopotentials, chest wall stimulation, and an external supraventricular arrhythmia simulator. The first method is simple and does not require additional equipment, even though in some patients adequate signals cannot be generated with a soft effort such as handgrip or hand compression. The main advantage of the chest wall stimulation method is the possibility that it be performed in every implanting center, since it is based on the use of standard devices for cardiac stimulation. The method based on the external supraventricular arrhythmia simulator allows the most detailed of the ECG traces, but it needs a dedicated electronic device.

Atrial Fibrillation↗

PubMed2004

Reduced mitral regurgitation in heart failure patients submitted to cardiac resynchronization therapy: a short-term prospective study.

BACKGROUND: The intraventricular delay is a determinant of functional mitral regurgitation (MR). MR contributes to the progression of congestive heart failure (CHF) and represents a marker of a worse outcome. The aim of this study was to test the hypothesis that cardiac resynchronization therapy (CRT) significantly reduces MR in CHF patients with ventricular conduction defects. METHODS: We studied 45 consecutive patients (37 males, 8 females, mean age 72 +/- 9 years) in NYHA class III-IV, with left ventricular ejection fraction < 35%, QRS duration > 150 ms with left bundle branch block or already paced in the right ventricle, and MR score > or = 1. We compared the QRS duration and the basal peak of the V-wave before and 15 min after CRT. Before implantation and 1 week after we measured ejection fraction, systolic mitral annulus diameter, MR area, left atrial area, MR area expressed as the percentage of the left atrial area (%MR area), and MR score (range 1-4). RESULTS: The QRS duration before and after CRT was 195 +/- 30 and 156 +/- 17 ms (p < 0.01) respectively. Significant decreases were observed in the systolic mitral annulus diameter (-7.9%, p < 0.001), MR area (-38%, p < 0.001), MR score (-33.4%, p < 0.001), left atrial area (-5.9%, p < 0.05), and %MR area (-36.2%, p < 0.001). The peak of the V-wave decreased by 33%. The ejection fraction increased by 46% (p < 0.001). CONCLUSIONS: CRT significantly reduces MR and improves cardiac function in patients with CHF and ventricular conduction defects. The combination of the degree of MR and a low ejection fraction and large QRS duration may contribute to a more reliable patient selection for CRT.

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PubMed2003

VDD pacemaker replacement independently of the implanted lead: a prospective study.

BACKGROUND: Single-lead VDD pacing is effective, safe and reliable. The only still open, practical issue is represented by the theoretical need of replacing each device with a similar one compatible with the already implanted lead to guarantee the performance of the system. The aim of our study was to investigate the atrial sensing performance of VDD pacemakers working in combination with non-dedicated chronic leads. METHODS: We enrolled 16 consecutive patients (12 males, 4 females, mean age 78 +/- 7 years) admitted to our institution for end of life of the battery. Atrial dipoles ranged from 5 to 30 mm. All replacements were done with a VDD(R) Saphir 3 (Vitatron) designed for an atrial dipole of 8.6 mm. RESULTS: All pacemakers were found to be performing well without any complaint by the patients imputable to stimulation defects. The P-wave amplitudes measured by the old and new pacemakers are similar and respectively 0.64 +/- 0.40 vs 0.73 +/- 0.53 mV (p = NS). So the old and new devices detect similar P waves. The atrial sensing percentage at 1 month of follow-up with the new pacemaker was even better than that of the old one (97 +/- 4 vs 95 +/- 3% respectively, p = 0.016): this is not imputable to the pacemaker but to the higher programmed atrial sensitivity (0.17 +/- 0.06 vs 0.18 +/- 0.07 mV respectively, p = NS). CONCLUSIONS: Independently of the implanted lead, the replacement of VDD pacemakers with devices designed for a short dipole is feasible, safe and reliable. This possibility overcomes a presumed limitation of this pacing modality.

Aged↗

PubMed2002

How to test mode switching in pacemakers implanted in patients: the MOST study.

Optimal management of atrial arrhythmias with dual chamber pacemakers requires proper performance of automatic mode switching (AMS). The aim of this study was to develop a reliable technique to test the AMS function by using an external electronic device capable of mimicking the occurrence of supraventricular arrhythmias (Supraventricular Arrhythmia Simulator [SAS]). The SAS delivers low voltage pulse trains (200 mV, 20 ms) through two skin electrodes. Each pulse train lasts 15 seconds and starts synchronously with a pacing pulse of the implanted pacemaker to avoid interference from the operator. The pulse train rate is set at 350, 250, and 160 beats/min to simulate AF, atrial flutter, and atrial tachycardia (AT), respectively. Thirty-five patients implanted with Vitatron pacemakers, whose AMS system has been previously validated, were enrolled. Atrial and ventricular sensing were programmed in unipolar mode at 0.5 mV and in bipolar mode at > 2 mV, respectively. All pulses from the SAS were detected by the atrial channel at an amplitude ranging from 1 to 3 mV. The test proved to be safe and reliable at rest and during exercise. AMS occurred immediately at onset or at offset of atrial arrhythmias, and no adverse interference on pacemaker function was seen from the SAS. In conclusion, the described technique and the SAS are safe and reliable for patient and pacemaker function and can be proposed as a useful method to verify proper performance of AMS function irrespective of the type of implanted devices.

Aged↗