Permanent His bundle pacing in patients with right atriomegaly: The value of different dedicated delivery sheaths.

BACKGROUND: An enlarged right atrium (RA) is a challenging anatomy that can limit the successful use of His bundle pacing (HBP). It is unknown whether new implantation tools could help overcome these challenges. METHODS: Consecutive patients with RA volume index >25 mL/m2 in men and >21 mL/m2 in women underwent permanent HBP. We used a stylet-driven lead (SDL) with an extendable helix delivered via a dedicated delivery sheath (Selectra 3D, Biotronik) as a first attempt. In case of failure, a second attempt was performed with the same lead but with a different delivery curve. Finally, a lumen-less lead (LLL) was also available as a third attempt. RESULTS: The study cohort included 24 patients (median age 75.7 years [interquartile range, 70.9-79.0], 88% men) with a RA volume of 49 mL/m2 (45-54). Using SDL, HBP was achieved with a single sheath curve in 17 patients (71%). The second attempt with the same lead but a different sheath was successful in four more patients (SDL success 87%). The fluoroscopy time increased significantly when the second attempt was necessary (8 min [6-11] vs. 15 min [13-17], p < .001). In the remaining three patients, HBP was further attempted with a LLL leading to a final procedural success of 96%. No lead dislodgment nor significant increase in pacing threshold was observed at 1-month (1.2 [0.7-1.7] V@1.0 ms vs. 1.1 [0.8-1.7] V@1.0 ms, p = .939). CONCLUSION: The availability of different dedicated delivery systems for HBP can improve procedural outcomes even in challenging circumstances, such as in patients with right atriomegaly.

The PhysioVP-AF study, a randomized controlled trial to assess the clinical benefit of physiological ventricular pacing vs. managed ventricular pacing for persistent atrial fibrillation prevention in patients with prolonged atrioventricular conduction: design and rationale.

AIMS: In patients with prolonged atrioventricular (AV) conduction and pacemaker (PM) indication due to sinus node disease (SND) or intermittent AV-block who do not need continuous ventricular pacing (VP), it may be difficult to determine which strategy to adopt. Currently, the standard of care is to minimize unnecessary VP by specific VP avoidance (VPA) algorithms. The superiority of this strategy over standard DDD or DDD rate-responsive (DDD/DDDR) in improving clinical outcomes is controversial, probably owing to the prolongation of the atrialventricular conduction (PR interval) caused by the algorithms. Conduction system pacing (CSP) may offer the most physiological-VP approach, providing appropriate AV conduction and preventing pacing-induced dyssynchrony. METHODS AND RESULTS: PhysioVP-AF is a prospective, controlled, randomized, single-blind trial designed to determine whether atrial-synchronized conduction system pacing (DDD-CSP) is superior to standard DDD-VPA pacing in terms of 3-year reduction of persistent-AF occurrence. Cardiovascular hospitalization, quality-of-life, and safety will be evaluated. Patients with indication for permanent DDD pacing for SND or intermittent AV-block and prolonged AV conduction (PR interval > 180 ms) will be randomized (1:1 ratio) to DDD-VPA (VPA-algorithms ON, septal/apex position) or to DDD-CSP (His bundle or left bundle branch area pacing, AV-delay setting to control PR interval, VPA-algorithms OFF). Approximately 400 patients will be randomized in 24 months in 13 Italian centres. CONCLUSION: The PhysioVP-AF study will provide an essential contribution to patient management with prolonged AV conduction and PM indication for sinus nodal disease or paroxysmal 2nd-degree AV-block by determining whether CSP combined with a controlled PR interval is superior to standard management that minimizes unnecessary VP in terms of reducing clinical outcomes.

Closed loop stimulation with His bundle lead placement.

Closed-loop stimulation (CLS; BIOTRONIK SE & Co. KG, Berlin, Germany) is a rate-responsive algorithm that analyzes intracardiac impedance trends using a standard lead placed in the right ventricle. It is unknown whether CLS could perform adequately with His bundle (HB) lead placement, as contractility dynamics may be attenuated in this region compared to the right ventricle apex.We performed hand-grip, mental, and bicycle exercise tests in a patient with brady atrial fibrillation and permanent HB pacing. The CLS algorithm responded with an appropriate heart rate to mental and physical tests. Learning objective: A combination of permanent His bundle and closed-loop stimulation-driven pacing may be a valid and physiological option for atrial fibrillation patients with chronotropic incompetence.

His-Purkinje system longitudinal dissociation: From bench to bedside. A case of output-dependent fascicular capture.

INTRODUCTION: Histological studies reported that the His bundle (HB) is partitioned into narrow cords by collagen running in its long axis, providing the anatomical setting necessary for its longitudinal dissociation. Further confirmations came from the demonstration that direct HB pacing normalizes the QRS axis and duration in subjects with proximal HB lesions causing bundle branch block. However, there is no evidence of the possibility of selective HB partitions pacing destined to the composition of branches and fascicles. METHODS AND RESULTS: We describe a case of intra-Hisian left bundle branch block in which permanent distal HB pacing corrects left ventricular delay and produces different QRS morphology at different voltage outputs, as an expression of different selective HB compartments recruitment. CONCLUSION: This case would strengthen the limited data in the literature about HB longitudinal dissociation.

Electrical storm in a patient with COVID-19 treated with hydroxychloroquine: A case report.

Hydroxychloroquine (HCQ) is a widely used drug to treat patients with coronavirus disease 19 (COVID-19). Although evidence of its efficacy and safety remains limited and controversial, both cardiac and non-cardiac adverse events are known to be associated with its use. To our knowledge, electrical storm in patients with COVID-19, or in any case treated with HCQ, has not been reported. We report the case of a 78-year-old male with an implantable cardiac resynchronization defibrillator (CRT-D) and a non-severe form of COVID-19. After a few days of home therapy with HCQ, an electrical storm was revealed that was associated with an increase in QTc. Following admission to the intensive care unit, HCQ was discontinued and progressive reduction of the QTc with electrical stabilization was observed. This clinical case highlights the potential risk of arrythmia associated with the use of HCQ and stresses the need for close electrocardiographic monitoring, especially in patients with established heart disease.

His bundle pacing: Clinical consequences of unnecessary right ventricle backup pacing.

As a backup lead in right ventricle (RV) is often used in His-bundle pacing (HBP) implants, in sinus rhythm patients the His lead is connected to the left ventricular (LV) port of a CRT device. In current devices, the backup pacing will be delivered 100% of time due to cross-channel ventricular refractory periods. Beyond an impact on battery, unnecessary RV pacing could find excitable tissue and capture a portion of the myocardium tissue potentially reducing the benefits of physiological HBP as shown in this case report where the switch from biventricular to LV-only pacing improved acute and 2-month echocardiography parameters.

Interatrial conduction time from electrograms of cardiac resynchronization therapy devices with left ventricular sensing.

BACKGROUND: The interatrial conduction time (IACT) is relevant for atrioventricular delay optimization in cardiac resynchronization therapy (CRT) devices. However, this information cannot be easily used as it requires invasive measurements. We tested whether electrical activation of left atrium (LA) could be detected in CRT devices with left ventricular (LV) sensing and used to estimate IACT. METHODS: The presence of LA activation on LV channel was evaluated in consecutive patients implanted with CRT and quadripolar LV leads whose sensing was temporarily set in the most proximal polarity (Ring LV4-housing). Estimates of IACT during sinus rhythm and atrial pacing were measured and compared with the values obtained with invasive catheterization of coronary sinus. RESULTS: Among six patients (50% female; mean age 73.3 ± 4.9 years) included in the analysis, four (66%) had a visible LA signal on the LV channel. The mean IACT measured with device electrograms was 71 ± 8 ms and 133 ± 15 ms during sinus rhythm and atrial pacing, respectively. These values were equivalent to the measurements obtained during invasive catheterization. Both patients without evidence of LA activation had an LV lead with a short total interelectrodes distance (46 mm) resulting in a significant anatomical distance between Ring LV4 and LA. CONCLUSIONS: In CRT devices with left ventricular sensing, LA signal could be detected and used to estimate IACT especially if long-spaced electrodes are used.

Alternative sites of ventricular pacing: His bundle pacing.

Since its introduction right ventricular apical (RVA) pacing has been the mainstay in cardiac pacing. However, in recent years there has been an upsurge of interest in permanent His bundle pacing (HBP), given the scientific evidence of the harmful role of dyssynchronous ventricular activation, induced by RVA pacing, in promoting the onset of heart failure and atrial fibrillation. After an intermediate period in which attention was focused on algorithms aimed at minimizing ventricular pacing, with partially inadequate and harmful results, scientific attention shifted to HBP, which proved to ensure a physiological electro-mechanical activation of the ventricles. The encouraging results obtained have allowed the introduction of HBP in recent guidelines for cardiac pacing in patients with bradicardia and cardiac conduction delay. Recent studies have also demonstrated the potential of HBP in patients with left bundle branch block and heart failure. HBP is promising as an attractive way to achieve physiological stimulation in patients with an indication for cardiac resynchronization therapy (CRT). Comparative studies of HB-CRT and biventricular pacing have shown similar results in numerically modest cohorts, although HB-CRT has been shown to promote better ventricular electrical resynchronization as demonstrated by a greater QRS narrowing. A widespread use of this pacing tecnique also depends on improvements in technology, as well as further validation of effectiveness in large randomised clinical trials.

Is dedicated implantation tool set really needed for permanent His bundle pacing?

This case describes the feasibility of permanent His bundle pacing (HBP) with a standard bipolar lead positioned through cephalic access without a dedicated delivery sheath. The use of a stylet pre-shaped on an echocardiographic reference allowed a successful procedure without specific technical difficulties. This "simplified" approach may provide some advantages with respect to the only commercially available system.

Usefulness of intracardiac echocardiography for the diagnosis of cardiovascular implantable electronic device-related endocarditis.

OBJECTIVES: The goal of this study was to compare transesophageal echocardiography (TEE) and intracardiac echocardiography (ICE) for the diagnosis of cardiac device-related endocarditis (CDI). BACKGROUND: The diagnosis of infective endocarditis (IE) was established by using the modified Duke criteria based mainly on echocardiography and blood culture results. No previous studies have compared ICE with TEE for the diagnosis of IE. METHODS: We prospectively enrolled 162 patients (age 72 ± 11 years; 125 male) who underwent transvenous lead extraction: 152 with CDI and 10 with lead malfunction (control group). Using the modified Duke criteria, we divided the patients with infection into 3 groups: 44 with a "definite" diagnosis of IE (group 1), 52 with a "possible" diagnosis of IE (group 2), and 56 with a "rejected" diagnosis of IE (group 3). TEE and ICE were performed before the procedure. RESULTS: In group 1, ICE identified intracardiac masses (ICM) in all 44 patients; TEE identified ICM in 32 patients (73%). In group 2, 6 patients (11%) had ICE and TEE both positive for ICM, 8 patients (15%) had a negative TEE but a positive ICE, and 38 patients (73%) had ICE and TEE both negative. In group 3, 2 patients (3%) had ICM both at ICE and TEE, 1 patient (2%) had an ICM at ICE and a negative TEE, and 53 patients (95%) had no ICM at ICE and TEE. ICE and TEE were both negative in the control group. CONCLUSIONS: ICE represents a useful technique for the diagnosis of ICM, thus providing improved imaging of right-sided leads and increasing the diagnostic yield compared with TEE.

Effect of low doses of alcohol on the warm-up phenomenon in patients with stable angina pectoris.

Experimental studies suggest that alcohol may have protective effects similar to that of ischemic preconditioning (IPC). The acute effects of alcohol on IPC in humans, however, are poorly known. In this study, we assessed the effect of alcohol administration on the warm-up phenomenon, as an expression of IPC, in patients with stable coronary artery disease (CAD). We randomized 45 stable CAD patients with positive (ST-segment depression > or =1 mm) exercise stress test to 1 of 3 groups of 15 patients each: (1) group 1 = 60 cc of gin (18.5 g of ethanol); (2) group 2 = 180 cc of red wine (18.9 g of ethanol); and (3) group 3 = placebo (120 cc of water). A first exercise test was performed 15 minutes after beverage administration. In those with a positive exercise test (13, 14, and 14 patients in the gin, wine, and placebo groups, respectively), a second exercise test was performed 15 minutes after the end of the first one. On the first test, there were no differences among groups in rate pressure product and time of exercise at 1-mm ST-segment depression, as well as in maximal ST segment depression. Furthermore, an improvement of the ischemic exercise variables was observed in each group, without any statistically significant differences among them. In conclusion, our data show that, in stable CAD patients, the acute intake of low doses of alcohol does not significantly influence IPC, as expressed by the warm-up phenomenon on exercise stress testing.

Exercise-induced ST-segment elevation in patients with a recent acute myocardial infarction treated by primary percutaneous coronary intervention.

OBJECTIVES: To get insight in the mechanism of exercise-induced ST-segment elevation (STE) in patients with Q/QS waves at the electrocardiogram (ECG). METHODS: We performed exercise stress test in 13 patients with anterior acute myocardial infarction treated by successful primary percutaneous coronary intervention (PCI). RESULTS: Compared to rest, an additional STE > or = 1 mm in one or more precordial ECG leads during exercise occurred in nine patients (69%), in the absence of symptoms. CONCLUSIONS: In acute myocardial infarction (MI) patients, treated by primary PCI and showing optimal coronary blood flow restoration at angiography, STE can still be induced by exercise in Q/QS wave ECG leads. This finding lends further support to the theory that exercise-induced STE in this clinical context is unlikely to represent by itself transient myocardial ischemia or viability.