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Biomedical subjects

Giuseppe Boriani

Publications and source records attributed to Giuseppe Boriani.

At least 37 records · Page 2Linked to original sources
PubMed2005

Electrocardiographic remodeling during cardiac resynchronization therapy.

BACKGROUND: More information is required on the relationship between electrical and structural reverse remodeling in patients treated with cardiac resynchronization therapy. METHODS: QRS and JT intervals were investigated during different pacing modes before and 3 months after implantation of a device for biventricular (BiV) pacing in 20 patients with severe drug-refractory heart failure (with left ventricular ejection fraction < 40% and QRS > 120 ms); structural remodeling was evaluated by echocardiography. RESULTS: QRS interval was significantly shortened by BiV pacing both acutely (p=0.002) and at 3 months (p=0.007). No significant change was found in the JT interval. The extent of QRS shortening obtained by BiV pacing showed moderate correlations with the reduction of end-systolic and end-diastolic volumes (r=0.53, p=0.016 and r=0.45, p=0.045, respectively) as well as with increase of left ventricular ejection fraction (r=0.49, p=0.028) at 3 months. The widening of QRS observed during right ventricular (RV) pacing was greater after 3 months of BiV pacing (with respect to acute assessments), suggesting accentuation of pacing-induced electrical dyssynchrony after a period of pacing-induced resynchronization. CONCLUSION: The extent of QRS shortening induced by BiV pacing appears to correlate with the reverse structural remodeling (in terms of reduction in end-systolic volume). The acute changes and the remodeling process occurring at mid-term in the overall population of CRT-treated patients do not appear to involve the JT interval. A period of pacing-induced resynchronization appears to accentuate the potential for RV pacing-driven electrical dyssynchrony.

Adult↗
PubMed2005

Implantable dual-chamber defibrillator for the selective treatment of spontaneous atrial and ventricular arrhythmias: arrhythmia incidence and device performance.

INTRODUCTION: Atrial tachyarrhythmias are a common co-morbidity in patients with an ICD indication. Recently introduced ICD's are equipped to independently detect and treat atrial and ventricular tachyarrhythmias. The purpose of this prospective study was to evaluate the incidence and termination of spontaneous atrial and ventricular tachyarrythmias in patients with a history of atrial tachyarrhythmias. METHODS AND RESULTS: Ninety patients, 70% male with an ICD indication and history of atrial tachyarrhythmia (LVEF 45 +/- 6%, [AT/AF indication 55 +/- 10, AT/VT 45 +/- 16], 46% CAD) were enrolled and 89 were implanted with a VENTAK PRIZM AVT (Guidant). Spontaneous atrial and ventricular tachyarrhythmias were printed and evaluated during an average follow-up period of 272 +/- 72 days utilizing the stored intracardial electrogram function of the device. Nineteen patients (21%) presented had only atrial tachyarrhythmias, 32 patients (36%) had both atrial and ventricular tachyarrhythmias and 18 patients (20%) had only ventricular tachyarrhythmias. Patients with only atrial tachyarrhythmias had a total of 3274 atrial episodes; 2002 terminated spontaneously, 1264 were treated with ATP and 8 with shock therapy. ATP was successful in 735 (58%) of 1264 episodes. Patients with both atrial and ventricular tachyarrhythmias had 7277 documented atrial tachyarrhythmias, 5231 terminated spontaneously, 1153 of 2009 were terminated by ATP (57.4%) and 37 by shock therapy (20 patient controlled). Atrial tachyarrhythmias identified as atrial flutter (AT) by the atrial rhythm classification (ARC) algorithm had a higher ATP conversion success rate than episodes identified as atrial fibrillation (AF); 66.7% for AT and 26.4% for AF. Patients with only ventricular tachyarrhythmias had 690 documented episodes, 401 terminated spontaneously, 248 (85.8%) were terminated by ATP and 41 by shock. CONCLUSION: Seventy-seven percent of patients with an ICD indication had spontaneous atrial and/or ventricular tachyharrhythmias within the first 6 months after ICD implantation. ATP therapy terminated 58% of all atrial tachyarrhytmias and 66.7% of the atrial flutters. The dual chamber ICD detected, classified and terminated all ventricular tacharrhythmias appropriately.

Aged↗
PubMed2005

Pacing with capture verification in candidates for resynchronisation therapy: a feasibility study.

BACKGROUND: Devices for cardiac resynchronisation therapy (CRT) deliver energy into 3 output channels. Such a burden can significantly reduce device longevity. Autocapture has been shown to improve pacemaker longevity and safety of right ventricular pacing in clinical studies. The aim of this study was to investigate the application of Autocapture during biventricular pacing (BIV) to decrease the energy cost of CRT. METHODS: During implantation of BIV devices, an acute study was performed to test the hypothesis that the evoked response (ER) elicited by each delivered stimulus is correctly detected and measured either on the right ventricular (RV) channel during BIV pacing with the left ventricular (LV) channel pacing first, or in the LV channel with the RV channel pacing first. A reliable measurement of ER is the critical requirement for the correct performance of Autocapture. RESULTS: ER amplitude in the right ventricle during BIV pacing was not significantly decreased compared with RV pacing in the VVI mode (16.36+/-5.27 mV vs 17.09+/-6.12 mV). ER amplitude in the left ventricle during BIV pacing was not significantly decreased compared with LV pacing in the VVI mode (12.4+/-8.95 mV vs 12.25+/-8.97 mV). Three patients in atrial fibrillation had a DDDR pacemaker with the LV lead connected to the atrial port, and received BIV pacing with Autocapture turned on in the RV channel. Autocapture performance in the long term, as assessed by the trend of RV threshold over 20+/-8 months, showed that LV depolarisation was never sensed as an ER on the RV channel. CONCLUSIONS: Our observations support the feasibility and safety of capture verification during BIV pacing on the ventricular channel paced secondly, which could increase the longevity of CRT devices, and decrease the costs of this new therapy for heart failure patients.

Algorithms↗
PubMed2005

Mechanisms of pain associated with internal defibrillation shocks: results of a randomized study of shock waveform.

BACKGROUND: Shock pain has limited the acceptance of the implantable atrial cardioverter and is a complication of ventricular implantable cardioverter-defibrillator therapy. Rounding off of the peak of a shock waveform reduces pain. Whether the pain reduction results from reduction in the peak voltage or from the rounding has not been established. In other words, does reducing the extreme dV/dt (voltage derivative) of the conventional truncated exponential capacitive discharge waveform reduce pain? OBJECTIVES: The purpose of this study was to compare the relative contributions of peak voltage and waveform shape to pain. METHODS: We compared rounded and conventional waveforms with equal peak voltages. Eighty-five shocks of 50 to 500 V were delivered to 10 patients requiring atrial cardioversion for persistent atrial fibrillation. The patient touched an analog pain scale (0-15 cm) and orally reported a pain score on a scale from 0 to 5. An observer scored thoracic contractions on a scale from 0 to 5. RESULTS: No differences between the rounded and conventional waveform on any scale were noted for either univariate or multivariate analyses. However, all three response scales were strongly predicted by voltage with r(2) = 0.77 (oral), r(2) = 0.86 (analog), and r(2) = 0.85 (contraction) after correcting for patient variability and including a log voltage term. CONCLUSIONS: Patient pain perception was determined primarily by waveform peak voltage and not by the rounding, per se.

Adult↗
PubMed2005

Long-term reduction of atrial tachyarrhythmia recurrences in patients paced for bradycardia-tachycardia syndrome.

BACKGROUND: Atrial tachyarrhythmias (AT) are considered progressive diseases. Several rhythm control therapies for treatment of AT have been proposed. OBJECTIVES: The Italian AT500 Registry was designed to prospectively study long-term AT evolution in patients paced for the brady-tachy form of sinus node disease (BT-SND). METHODS: Three hundred forty-six BT-SND patients received an antitachycardia dual-chamber pacemaker and were followed-up for a minimum of 12 months (median 19 months). Prevention and antitachycardia pacing (ATP) features were enabled in all patients. RESULTS: During the observation period, 224 (65%) patients were treated by antiarrhythmic drugs and 45 (13%) patients were cardioverted. Five patients suffered a stroke, 4 transient ischemic attack, 22 permanent AT, and 98 AT recurrences longer than 7 days. AT mean cycle length changed from 246 to 270 ms, and the percentage of patients with AT-related hospitalizations significantly decreased with an annual 28% relative reduction. AT burden and the percentage of patients with AT recurrences longer than 2 days remained constant with time in the overall population but decreased significantly in the subgroup of patients who did not develop permanent AT. High ATP efficacy was associated with an increasingly higher prevention of AT recurrences longer than 2 days. CONCLUSION: In a long-term observation of BT-SND patients, AT-related hospitalizations decreased significantly and mean AT cycle length increased significantly. The data suggest that rhythm control therapies induce inversion of AT progression.

Aged↗
PubMed2005

Quantification of fatty tissue mass by magnetic resonance imaging in arrhythmogenic right ventricular dysplasia.

INTRODUCTION: Arrhythmogenic right ventricular dysplasia (ARVD) is a heart muscle disorder in which the pathological substrate is a fatty or fibro-fatty replacement of the right ventricular (RV) myocardium. METHODS AND RESULTS: Magnetic resonance imaging (MRI) studies were performed in 10 patients with arrhythmogenic right ventricular dysplasia and in 24 matched controls in order to assess right ventricular epicardial/intramyocardial fatty tissue mass, RV myocardial mass, and RV functional parameters. Functional abnormalities were found in all ARVD cases. Patients with ARVD showed increased fatty tissue compared to controls (8.2 +/- 4 g vs. 2.0 +/- 1.0 g; P = 0.001), whereas no significant differences were found in RV myocardial mass (29.5 +/- 9.2 g vs. 23.2 +/- 6.7 g; P = NS). A correlation coefficient between 0.87 and 0.97 was found for repeated measurements. CONCLUSION: Quantification of fatty tissue with MRI is feasible and constitutes an objective method for differentiating normal from pathological conditions. This approach may lead to a complete diagnostic assessment of ARVD with the potential application for monitoring the evolution of the disease.

Adipose Tissue↗
PubMed2005

Cardiac resynchronization therapy: effects on left and right ventricular ejection fraction during exercise.

In patients with heart failure and wide QRS complex, cardiac resynchronization therapy (CRT) is associated with improvement of symptoms and cardiac function. This study examined the effects of a 3-month period of CRT on left ventricular (LV) and right ventricular (RV) ejection fraction (EF) and on LV volumes, both at rest and during exercise. A CRT system was implanted in 15 patients with severe heart failure and wide QRS. Before implant and 3 months later, all patients underwent assessment of cardiac performance with equilibrium Tc(99) radionuclide angiography with imaging in the best septal left anterior oblique view. Exercise was performed on a bicycle ergometer. At 3 months, a significant improvement in New York Heart Association functional class was observed, and radionuclide angiography showed a significant decrease in LV volumes and a significant increase in LVEF at rest, as well as a significant increase in LVEF during exercise. The remodeling processes associated with CRT did not appear to include RV function, since RVEF did not improve, and changes in RVEF did not correlate with changes in LVEF, neither at rest nor during exercise.

Cardiac Pacing, Artificial↗
PubMed2005

Evaluation of fusion beat detection with a new ventricular automatic capture algorithm in ICDs.

This study evaluated a newly developed automatic capture verification scheme for implantable cardioverter defibrillators (ICDs) regarding discrimination of capture, fusion, and noncapture beats, with an emphasis on fusion detection. The algorithm uses evoked response detection based on a sensing vector from right ventricular shocking coil to Can. Patients undergoing ICD implant or replacement were enrolled in this study. An external system was used for pacing and data acquisition. To provoke ventricular fusion beats, VVI patients were paced close to the rate of their intrinsic rhythm and DDD patients were paced close at their intrinsic PR interval. Surface ECG and wideband filtered intracardiac electrograms were recorded for off-line analysis. Each paced beat was independently classified visually by surface ECG and by the automatic detection algorithm. The algorithm performance was then evaluated by comparing the classification results. Twenty-seven patients (22 males, 5 females; 63.8 +/- 12.5 years) were analyzed. Device and lead demographics were: 18 DDD/9 VVI; 16 dedicated bipolar, 11 integrated bipolar leads; 18 acute, 9 chronic (3.7 +/- 2.0 years) leads. In total, 2064 beats were analyzed, including 1,477 fusion beats and 587 capture beats. Fusion detection sensitivity and specificity were 99.5% and 99.0%, respectively. Seven true-fusion beats (0.5%) were classified as capture and 6 capture beats (1.0%) were identified as fusions. Capture or fusion beats were never detected as non-capture beats. It is concluded that the algorithm was effective in detecting fusion beats. It could potentially be used in ICD applications that need accurate fusion detection.

Algorithms↗
PubMed2005

Evaluation of the atrial evoked response for capture detection with high-polarization leads.

AutoCapture based on the evoked response can be confounded by electrode polarization. In this study, polarization was measured in human subjects who had chronic atrial leads. The aim of the study was to determine whether electrode polarization can be measured using a time integral atrial evoked-response integral (AERI) of the negative portion of the atrial paced ER evoked-response signal and to determine whether high-polarization atrial leads unsuitable for AutoCapture can be identified a priori. Atrial intracardiac-electrogram (IEGM) signals from 39 patients with implanted pacemakers were recorded and analyzed. The signals were recorded during conventional atrial-threshold searches. A total of 221 atrial-capture thresholds were recorded, ranging from 0.25 to 2.75 V with a mean of 0.79 V. Each evoked response was evaluated using the AERI in a 36 ms window following the 0.4 ms atrial stimulus. The polarization was estimated as a linear function of stimulus voltage using the evoked-response signal integral of captured beats identified on the IEGM. The 221 threshold-search datasets were obtained using leads with eight different electrode materials. Polarization could be measured using AERI as a function of stimulus voltage. Furthermore, this polarization measure can be used to identify high-polarization leads, which are ill suited for the atrial AutoCapture algorithm.

Aged↗
PubMed2005

Predictors of atrial antitachycardia pacing efficacy in patients affected by brady-tachy form of sick sinus syndrome and implanted with a DDDRP device.

UNLABELLED: Predictors of ATP efficacy in brady/tachy patients. BACKGROUND: Recent options to treat atrial tachyarrhythmias (ATA) include implantable devices delivering antitachycardia pacing therapies (ATP). No prospective study selected patients with higher chances of episode termination by ATP or indicated the most effective ATP use. Our aim was to study ATP efficacy in patients with brady-tachy form of sinus node disease (SND), identifying clinical factors, ATA characteristics, and device features predicting ATP efficacy. METHODS AND RESULTS: Three hundred and sixteen patients (105 M, aged 71.1+/-8.8 years) received a DDDRP pacemaker and were prospectively followed. Median follow-up was 18 months: 37,125 ATA episodes occurred in 217 patients; ATP treated 5,536 of them. Overall, ATP efficacy was 50.0%. A multivariate analysis identified longer arrhythmia cycle lengths (OR=1.25; CI=1.07-1.47) and shorter delays to ATP delivery (OR=0.15; CI=0.10-0.22) as independent predictors of ATP efficacy for episodes preceded by >or=5 minutes of sinus rhythm. Additionally, ATP efficacy for all treated episodes was predicted by lower New York Heart Association (NYHA) class (OR=0.64; CI=0.42-0.98), episode classification as nonimmediate recurrence of ATA (non-IRAT) (OR=0.07; CI=0.02-0.33), absence of overlap in the device detection windows (OR=0.54; CI=0.32-0.91), and flecainide treatment (OR=2.22; CI=1.04-4.71). CONCLUSIONS: In patients paced for SND, multivariate analysis shows that ATP efficacy is associated to longer arrhythmia cycle lengths, shorter ATP delivery delays, NYHA class I, episode classification as non-IRAT, absence of overlap in the atrial arrhythmia device detection windows, and flecainide treatment.

Aged↗
PubMed2005

Comparison of induced and spontaneous atrial tachyarrhythmias in patients with a history of spontaneous atrial tachyarrhythmias.

INTRODUCTION: This retrospective study investigated whether induced episodes could be used to predict the morphology of future spontaneous atrial episodes. METHODS: Eighty-two patients (64 +/- 12 years; 77% male; CAD in 60%; left ventricular ejection fraction 45 +/- 16%) with a history of atrial tachycardia or atrial fibrillation (AT/AF) were implanted with a dual-chamber implantable cardioverter defibrillator (ICD) and followed for 6 months. A total of 224 episodes of induced and spontaneous AT/AF were classified into type I, II, and III according to the method of Israel et al. and then compared based on average cycle length (CL) and atrial amplitude. Episodes were also grouped as "pace-terminable" or "nonpace-terminable" based on the CL definition of Gillis et al. RESULTS: The analysis of 121 induced episodes (from 80 patients) and 103 spontaneous episodes (from 43 patients) showed that within each arrhythmia type, there were no significant differences in CL or mean amplitude between induced and spontaneous episodes. Additional analysis of patients that had both induced and spontaneous episodes (n = 41) showed 78% had at least one spontaneous episode that matched the induced episode. Fifty-seven percent of spontaneous episodes were considered to be pace-terminable based on CL. CONCLUSIONS: Our data suggest that there is no significant difference between induced and spontaneous episodes of AT/AF of the same type. The majority of patients had at least one spontaneous episode of the same type as the induced episode, showing that induced atrial arrhythmias may be useful in predicting the morphology of future spontaneous episodes and in identifying patients potentially benefiting from atrial antitachycardia pacing.

Adult↗
PubMed2005

Atrial fibrillation in patients with a dual defibrillator: characteristics of spontaneous and induced episodes and effect of ventricular tachyarrhythmia induction.

BACKGROUND: The pattern of FF intervals during atrial fibrillation (AF) has been analyzed in induced and spontaneous AF episodes, after the induction of ventricular fibrillation (VF) and after atrial shock, in order to suggest practical considerations for AF management in patients implanted with antitachycardia devices. METHODS: In 13 patients implanted with a dual-chamber defibrillator, FF intervals were analyzed during two separate induced AF episodes, before and after VF induction over AF, as well as during spontaneous AF episodes and after unsuccessful atrial shocks. The following parameters were considered: mean atrial cycle length (CL), atrial CL stability, and standard deviation of the atrial cycle. RESULTS: The AF pattern had comparable characteristics considering two separate inductions of AF, as well as spontaneous AF episodes. Ventricular tachyarrhythmia induction resulted in a shortening of atrial CL (P < 0.02) and in a less organized AF pattern (P < 0.005). Changes in the FF interval after ineffective shock therapy showed a shortening of AF cycles after shocks with energies far below the defibrillation threshold. CONCLUSIONS: (a) The AF pattern is reproducible in separate inductions of sustained AF and in spontaneous episodes, (b) dynamic changes involving a shortening of the AF cycle and an evolution to a less homogeneous pattern occur after VF induction, revealing a complex interplay between AF and VF, and (c) FF interval analysis after ineffective shock delivery may allow the relationship between delivered shock energy and effective defibrillation energy to be estimated, thereby providing practical suggestions for step-up protocols in atrial cardioversion.

Atrial Fibrillation↗
PubMed2004

Temporal variability of atrial tachyarrhythmia burden in bradycardia-tachycardia syndrome patients.

AIMS: Several studies have tested non-pharmacological therapies for atrial tachyarrhythmias (ATs) by measuring the cumulative time (burden) the patient spends in arrhythmia. Contradictory results questioned either therapy efficacy or statistical power of the trials. We studied AT burden variability in patients paced for sinus node disease (SND) in order to interpret currently published data appropriately and to evaluate reliable sample sizes. METHODS AND RESULTS: One hundred and five patients with AT and SND received a dual chamber pacemaker with antitachyarrhythmia-pacing capability, and were followed for 13 months. Seventy-eight patients (74%) suffered AT recurrences. Device-gathered diagnostic measures were used to simulate results of randomized studies both with crossover and parallel design. The sample size required for statistically significant results was calculated as a function of the expected therapy-induced burden reduction. AT burden intra-patient variability was high: 43% of patients showed intrinsic fluctuations hiding any therapy-induced burden reduction lower than 30%. Demonstrating therapeutic breakthrough through a 6 month study would require 290 patients with crossover design and 5800 patients with parallel design. Doubling the study period requires 400 and 3000 patients, respectively. CONCLUSION: Patients with AT and paced for SND showed high intra-patient burden variability, which could possibly hide an AT burden reduction induced by a therapy. Previous studies involving non-pharmacological therapies utilizing AT burden endpoints could lack the power to reach statistical significance.

Aged↗