Massimiliano Maines

Permanent His-bundle pacing maintains long-term ventricular synchrony and left ventricular performance, unlike conventional right ventricular apical pacing

AIMS Right ventricular apical pacing (RVAP) may be deleterious, determining abnormal left ventricular (LV) electrical activation and progressive LV dysfunction. Permanent His-bundle pacing (HBP) has been proposed to prevent this detrimental effect. The aim of our study was to compare the long-term effects of HBP on LV synchrony and systolic performance with those of RVAP in the same group of patients. METHODS Our analysis included 26 patients who received both an HBP lead and an RVAP lead, as backup, in our electrophysiology laboratory between 2004 and 2007. After implantation, all devices were programmed to obtain HBP. An intra-patient comparison of the effects of HBP and RVAP on LV dyssynchrony and function was performed at the last available follow-up examination. RESULTS After a mean of 34.6 ± 11 months, the pacing modality was temporarily switched to RVAP. During RVAP, LV ejection fraction significantly decreased (50.1 ± 8.8% vs. 57.3 ± 8.5%, P < 0.001), mitral regurgitation significantly increased (22.5 ± 10.9% vs.16.3 ± 12.4%; P = 0.018), and inter-ventricular delay significantly worsened (33.4 ± 19.5 ms vs. 7.1 ± 4.7 ms, P = 0.003) in comparison with HBP. However, the myocardial performance index was not statistically different between the two pacing modalities (P = 0.779). No asynchrony was revealed by tissue Doppler imaging during HBP, while during RVAP the asynchrony index was significantly higher in both the four-chamber (125.8 ± 63.9 ms; P = 0.035 vs. HBP) and two-chamber (126 ± 86.5 ms; P = 0.037 vs. HBP) apical views. CONCLUSION His-bundle pacing has long-term positive effects on inter- and intra-ventricular synchrony and ventricular contractile performance in comparison with RVAP. It prevents asynchronous pacing-induced LV ejection fraction depression and mitral regurgitation.

Intrathoracic and Ventricular Impedances are Associated with Changes in Ventricular Volume in Patients Receiving Defibrillators for CRT

Background: Some implantable cardioverter defibrillators (ICD) are able to monitor intrathoracic impedance to detect pulmonary fluid overload. This is achieved by measuring impedance between the ICD case and the right ventricular (RV) lead. We hypothesized that the measured impedance would rise with improvement in left ventricular (LV) volumes during cardiac resynchronization therapy (CRT), and that such impedance changes would be more apparent when measured with an alternative pacing vector.

Intrathoracic impedance and pulmonary wedge pressure for the detection of heart failure deterioration

AIMS The aims of this analysis were to assess the agreement between implantable defibrillator (ICD)-measured intrathoracic impedance and pulmonary capillary wedge pressure (PCWP) collected during long-term follow-up, as well as to evaluate whether PCWP measures may improve the performance of the impedance detection algorithm in predicting heart failure (HF) worsening. METHODS AND RESULTS We studied 23 HF patients implanted with an ICD capable of intrathoracic impedance measurement and alerting for fluid accumulation diagnosis. At regular follow-up and at visits for HF decompensation or device alert, clinical status was assessed and PCWP was non-invasively estimated with a validated echo-Doppler method. During 23 +/- 11 months, 45 paired assessments of impedance and PCWP were performed. The Kappa analysis revealed good agreement between impedance and PCWP (k = 0.701, SE 0.113, P < 0.001). Moreover, PCWP estimations and the paired values of the impedance fluid index resulted significantly correlated (r = 0.677, P < 0.001). The impedance-alert detected clinical HF deterioration with 92% sensitivity and 69% positive predictive value. The combined finding of decreased impedance and increased PCWP resulted in enhanced positive predictive value (92%) and no change in sensitivity (92%). CONCLUSION These data confirm the inverse correlation between impedance and PCWP at long-term follow-up and suggest the potential clinical value of a combined impedance and pressure assessment for the improved detection of HF deterioration.

Intrathoracic Impedance and Ultrasound Lung Comets in Heart Failure Deterioration Monitoring

Purpose: Echographic examination of the lung surface may reveal multiple ultrasound lung comets (ULCs) originating from water‐thickened interlobular septa. These images were demonstrated to be useful for noninvasive assessment of interstitial pulmonary edema. Similarly, the correlation between implantable defibrillator‐measured intrathoracic impedance and pulmonary capillary wedge pressure (PCWP) was demonstrated in heart failure (HF) patients. The aims of this analysis were to assess the agreement between defibrillator‐detected impedance decrease and the presence of ULCs, as well as to compare the performance of the impedance‐detection algorithm and the ULCs assessment in predicting HF worsening.

Computational generation of the Purkinje network driven by clinical measurements: The case of pathological propagations

To properly describe the electrical activity of the left ventricle, it is necessary to model the Purkinje fibers, responsible for the fast and coordinate ventricular activation, and their interaction with the muscular propagation. The aim of this work is to propose a methodology for the generation of a patient-specific Purkinje network driven by clinical measurements of the activation times related to pathological propagations. In this case, one needs to consider a strongly coupled problem between the network and the muscle, where the feedback from the latter to the former cannot be neglected as in a normal propagation. We apply the proposed strategy to data acquired on three subjects, one of them suffering from muscular conduction problems owing to a scar and the other two with a muscular pre-excitation syndrome (Wolff-Parkinson-White). To assess the accuracy of the proposed method, we compare the results obtained by using the patient-specific Purkinje network generated by our strategy with the ones obtained by using a non-patient-specific network. The results show that the mean absolute errors in the activation time is reduced for all the cases, highlighting the importance of including a patient-specific Purkinje network in computational models.

Comparison between low-dose dobutamine echocardiography and thallium-201 scintigraphy in the detection of myocardial viability in patients with recent myocardial infarction

AIM To compare the predictive value of thallium-201 single photon emission computed tomography (SPECT) scintigraphy (Sci) and low-dose dobutamine echocardiography (Dob) in predicting late recovery of dysfunctioning myocardium in patients with recent, uncomplicated myocardial infarction (MI). METHODS AND RESULTS 19 patients (18 male, aged 58+/-8 years) with recent MI and ejection fraction <50% (35.5+/-8.3%) underwent 5-15 microg/kg per min Dob, rest-redistribution Sci and coronary angiography, respectively, 14+/-6, 16+/-7 and 17+/-5 days after MI. On an eleven-segment ventricular model devised to compare Dob and Sci segment by segment, each dysfunctioning ventricular segment was considered viable if it showed recovery of mechanical function at the echocardiographic follow-up, performed 6.3+/-1.5 months after revascularization (five PTCA, five GABG) or medical therapy. Among the 104 dysfunctioning segments, of which 26 (25%) showed recovery at follow-up, Dob and Sci gave a concordant response in 50 (48%, k = 0.13), correctly predicting the recovery (or not) of function in 42. Forty-two of 54 discordant responses were due to segments judged viable only by Sci and which had no recovery at follow-up (of these 37 were akinetic or severely hypokinetic at baseline). At the segment-by-segment analysis, the sensitivity, specificity, and accuracy in predicting recovery of function at follow-up were, respectively, 69, 88 and 84% for Dob as against 88, 36 and 49% for Sci (P<0.001 for both specificity and accuracy, P=NS for sensitivity). CONCLUSION In patients with recent MI, the specificity of Dob in the detection of myocardium capable of late mechanical recovery is significantly higher with respect to Sci, whereas sensitivity is slightly, not significantly higher for the latter. It is conceivable that Sci detects viable myocardium even if it is transmurally limited to epicardial layers in segments with severely impaired mechanical function in which viability will not affect late recovery of function.

ICD and Neuromodulation Devices: Is Peaceful Coexistence Possible?

Aim: The aim of this study was to investigate the potential cross‐talk between implantable cardioverter defibrillator device (ICD) and implantable neuromodulation device (IND) during the implantation procedure and the ventricular fibrillation induction test and in daily life.

Clinical impact, safety, and accuracy of the remotely monitored implantable loop recorder Medtronic Reveal LINQTM

Aims Implantable loop recorders (ILR) are indicated in a variety of clinical situations when extended cardiac rhythm monitoring is needed. We aimed to assess the clinical impact, safety, and accuracy of the new Medtronic Reveal LINQTM ILR that can be inserted outside the electrophysiology (EP) laboratory and remotely monitored. Methods and results All 154 consecutive patients (100 males, 63 ± 15 year-old) who received the Reveal LINQTM ILR during the period July 2014-June 2016 were enrolled. The device was implanted in a procedure room and all patients where provided with the MyCareLinkTM remote monitoring system. Data were reviewed every working day via the Carelink® web system by a specialist nurse who, in case of significant events, consulted an electrophysiologist. During a mean follow-up of 12.1 (6.7-18.4) months (range 2-24 months), a diagnosis was made in 99 (64%) patients and in 60 (39%) ≥1 therapeutic interventions were established following recording of arrhythmias. In 26 of these 60 patients, remote monitoring prompted therapeutic interventions following asymptomatic arrhythmic events 3.8 months before the next theoretical scheduled in-office data download. False bradycardia detection for undersensing occurred in 44 (29%) patients and false tachycardia detection for oversensing in 4 (3%). One patient experienced skin erosion requiring explantation and none suffered from infection. Conclusion The remote monitoring feature of the Reveal LINQTM allowed earlier diagnosis of asymptomatic but serious arrhythmias in a significant proportion of patients. Implantation of the device outside the EP laboratory appeared safe. However, R-wave undersensing and consequent false recognition of bradyarrhythmias remains a clinically important technical issue.

Physiopathologic Correlates of Intrathoracic Impedance in Chronic Heart Failure Patients

Background: Increased plasma levels of amino‐terminal fraction of brain natriuretic peptide (NT‐proBNP) and alterations of diastolic filling as described by Doppler transmitral flow pattern are well‐known markers of decompensated heart failure (HF). Recently, some implantable defibrillators have allowed monitoring of intrathoracic impedance, which is related to lung water content, potentially indicating HF deterioration. The aim of this study was to assess the correlation between intrathoracic impedance and NT‐proBNP and echo‐Doppler transmitral flow indexes.

Three-dimensional electroanatomic mapping system-enhanced cardiac resynchronization therapy device implantation: Results from a multicenter registry.

Cardiac resynchronization therapy (CRT) device implantation guided by an electroanatomic mapping system (EAMS) is an emerging technique that may reduce fluoroscopy and angiography use and provide information on coronary sinus (CS) electrical activation. We evaluated the outcome of the EAMS‐guided CRT implantation technique in a multicenter registry.