Predictors of the efficacy of His bundle pacing in patients with a prolonged PR interval: A stratified analysis of the HOPE-HF randomized controlled trial.

AIMS: The randomized, double-blind, placebo-controlled HOPE-HF trial assessed the benefit of atrio-ventricular (AV) delay optimization delivered using His bundle pacing. It recruited patients with left ventricular ejection fraction ≤40%, PR interval ≥200 ms, and baseline QRS ≤140 ms or right bundle branch block. Overall, there was no significant increase in peak oxygen uptake (VO2max) but there was significant improvement in heart failure specific quality of life. In this pre-specified secondary analysis, we evaluated the impact of baseline PR interval, echocardiographic E-A fusion, and the magnitude of acute high-precision haemodynamic response to pacing, on outcomes. METHODS AND RESULTS: All 167 randomized participants underwent measurement of PR interval, acute haemodynamic response at optimized AV delay, and assessment of presence of E-A fusion. We tested the impact of these baseline parameters using a Bayesian ordinal model on VO2max, quality of life and activity measures. There was strong evidence of a beneficial interaction between the baseline acute haemodynamic response and the blinded benefit of pacing for VO2 (Pr 99.9%), Minnesota Living With Heart Failure (MLWHF) (Pr 99.8%), MLWHF physical limitation score (Pr 98.9%), EQ-5D visual analogue scale (Pr 99.6%), and exercise time (Pr 99.4%). The baseline PR interval and the presence of baseline E-A fusion did not have this reliable ability to predict the clinical benefit of pacing over placebo across multiple endpoints. CONCLUSIONS: In the HOPE-HF trial, the acute haemodynamic response to pacing reliably identified patients who obtained clinical benefit. Patients with a long PR interval (≥200 ms) and left ventricular impairment who obtained acute haemodynamic improvement with AV-optimized His bundle pacing were likely to obtain clinical benefit, consistent across multiple endpoints. Importantly, this gradation can be reliably tested for before randomization, but does require high-precision AV-optimized haemodynamic assessment to be performed.

Tricuspid valve disease and cardiac implantable electronic devices.

The role of cardiac implantable electronic device (CIED)-related tricuspid regurgitation (TR) is increasingly recognized as an independent clinical entity. Hence, interventional TR treatment options continuously evolve, surgical risk assessment and peri-operative care improve the management of CIED-related TR, and the role of lead extraction is of high interest. Furthermore, novel surgical and interventional tricuspid valve treatment options are increasingly applied to patients suffering from TR associated with or related to CIEDs. This multidisciplinary review article developed with electrophysiologists, interventional cardiologists, imaging specialists, and cardiac surgeons aims to give an overview of the mechanisms of disease, diagnostics, and proposes treatment algorithms of patients suffering from TR associated with CIED lead(s) or leadless pacemakers.

Effects of haemodynamically atrio-ventricular optimized His bundle pacing on heart failure symptoms and exercise capacity: the His Optimized Pacing Evaluated for Heart Failure (HOPE-HF) randomized, double-blind, cross-over trial.

AIMS: Excessive prolongation of PR interval impairs coupling of atrio-ventricular (AV) contraction, which reduces left ventricular pre-load and stroke volume, and worsens symptoms. His bundle pacing allows AV delay shortening while maintaining normal ventricular activation. HOPE-HF evaluated whether AV optimized His pacing is preferable to no-pacing, in a double-blind cross-over fashion, in patients with heart failure, left ventricular ejection fraction (LVEF) ≤40%, PR interval ≥200 ms and either QRS ≤140 ms or right bundle branch block. METHODS AND RESULTS: Patients had atrial and His bundle leads implanted (and an implantable cardioverter-defibrillator lead if clinically indicated) and were randomized to 6 months of pacing and 6 months of no-pacing utilizing a cross-over design. The primary outcome was peak oxygen uptake during symptom-limited exercise. Quality of life, LVEF and patients' holistic symptomatic preference between arms were secondary outcomes. Overall, 167 patients were randomized: 90% men, 69 ± 10 years, QRS duration 124 ± 26 ms, PR interval 249 ± 59 ms, LVEF 33 ± 9%. Neither peak oxygen uptake (+0.25 ml/kg/min, 95% confidence interval [CI] -0.23 to +0.73, p = 0.3) nor LVEF (+0.5%, 95% CI -0.7 to 1.6, p = 0.4) changed with pacing but Minnesota Living with Heart Failure quality of life improved significantly (-3.7, 95% CI -7.1 to -0.3, p = 0.03). Seventy-six percent of patients preferred His bundle pacing-on and 24% pacing-off (p < 0.0001). CONCLUSION: His bundle pacing did not increase peak oxygen uptake but, under double-blind conditions, significantly improved quality of life and was symptomatically preferred by the clear majority of patients. Ventricular pacing delivered via the His bundle did not adversely impact ventricular function during the 6 months.

Contrast-enhanced magnetic resonance imaging for the detection of ruptured coronary plaques in patients with acute myocardial infarction.

PURPOSE: X-ray coronary angiography (XCA) is the current gold standard for the assessment of lumen encroaching coronary stenosis but XCA does not allow for early detection of rupture-prone vulnerable plaques, which are thought to be the precursor lesions of most acute myocardial infarctions (AMI) and sudden death. The aim of this study was to investigate the potential of delayed contrast-enhanced magnetic resonance coronary vessel wall imaging (CE-MRCVI) for the detection of culprit lesions in the coronary arteries. METHODS: 16 patients (13 male, age 61.9±8.6 years) presenting with sub-acute MI underwent CE-MRCVI within 24-72h prior to invasive XCA. CE-MRCVI was performed using a T1-weighted 3D gradient echo inversion recovery sequence (3D IR TFE) 40±4 minutes following the administration of 0.2 mmol/kg gadolinium-diethylenetriamine-pentaacetic acid (DTPA) on a 3T MRI scanner equipped with a 32-channel cardiac coil. RESULTS: 14 patients were found to have culprit lesions (7x LAD, 1xLCX, 6xRCA) as identified by XCA. Quantitative CE-MRCVI correctly identified the culprit lesion location with a sensitivity of 79% and excluded culprit lesion formation with a specificity of 99%. The contrast to noise ratio (CNR) of culprit lesions (9.7±4.1) significantly exceeded CNR values of segments without culprit lesions (2.9±1.9, p<0.001). CONCLUSION: CE-MRCVI allows the selective visualization of culprit lesions in patients immediately after myocardial infarction (MI). The pronounced contrast uptake in ruptured plaques may represent a surrogate biomarker of plaque activity and/or vulnerability.

Persistent atrial fibrillation presenting in sinus rhythm: pulmonary vein isolation versus pulmonary vein isolation plus electrogram-guided ablation.

BACKGROUND: The classification of atrial fibrillation as paroxysmal or persistent (PsAF) is clinically useful, but does not accurately reflect the underlying pathophysiology and is therefore a suboptimal guide to selection of ablation strategy. AIM: To determine if additional substrate ablation is beneficial for a subset of patients with PsAF, in whom long periods of sinus rhythm (SR) can be maintained. METHODS: We included patients presenting with PsAF in whom continuous periods of SR>3months were documented. All patients were in SR on the day of the procedure. Electrical pulmonary vein isolation (PVI) was performed in all patients. Additional electrogram (EGM)-guided ablation was left to the discretion of the operator. Patient characteristics and follow-up were analysed with respect to presence or absence of additional EGM-guided ablation. RESULTS: Sixty-five patients (mean age 60.1±8.9years; 81.5% men) met the inclusion criteria. EGM-guided ablation was performed in 32 (49%) patients. Patients with and without EGM-guided ablation had similar baseline characteristics. Absence of EGM-guided ablation was one of the independent predictors for arrhythmia recurrences after the index procedure (hazard ratio 0.24; confidence interval 0.12-0.47). After a median follow-up of 18±10months, the number of procedures required was significantly higher in the 'PVI-only' group (2.24±0.75 vs. 1.84±0.81; P=0.04) to achieve a similar success rate (84% vs. 81%; P=0.833). CONCLUSION: The addition of EGM-guided ablation requires fewer procedures to achieve similar clinical efficacy in mid-term follow-up compared with a PVI-only strategy in patients with PsAF presenting for ablation in SR.

Single site left ventricular pacing induced dyssynchrony and cardiomyopathy.

Single site left ventricular (LV) pacing in the absence of intrinsic ventricular activity can be as detrimental to LV function as right ventricular apical pacing. This report describes a patient with complete heart block who developed significant dyssynchrony and cardiomyopathy secondary to single site lateral LV pacing. The process was reversed by placement of a second anterior LV lead.

Future of cardiac resynchronization therapy.

Cardiac resynchronization therapy (CRT) has proven to be a beneficial treatment option in patients with severe drug refractory heart failure in the presence of electromechanical dyssynchrony. More recent trials have demonstrated mortality benefits associated with CRT, and even further reductions when combined with an internal cardiac defibrillator. Addressing the 20-30% cohort of patients who do not derive benefit from this novel therapy is a rapidly emerging area of research activity with encouraging results. Here we review the CRT trial evidence that forms the basis of patient-selection guidelines for device implantation and describe the present outstanding issues, alongside identifying future trends in CRT that appear promising.

Occurrence of atrial fibrillation after flutter ablation: the significance of intra-atrial conduction and atrial vulnerability.

Atrial vulnerability and intra-atrial conduction delay are important substrates for paroxysmal atrial fibrillation (AFib); however, their significance is unknown in patients undergoing atrial flutter ablation. Antegrade (high right atrium to coronary sinus: HRA-CS) and retrograde (CS-HRA) intra-atrial conduction times and AFib inducibility were assessed in 61 patients undergoing ablation for type I atrial flutter. Twenty-three patients had structural heart disease and 18 AFib before the procedure. After 16 +/- 12 months of follow-up 17 patients experienced AFib, 5 of which progressed into chronic AFib. During the study, AFib was easily inducible in 14 patients, 7 of which developed AFib (P =.03). Patients with post- ablation AFib were older (59 +/- 11 vs. 44 +/- 15 years, P =.001), had longer intra-atrial conduction times before (98 +/- 17 ms vs. 68 +/- 20 ms, P <.001) and after ablation (91 +/- 19 ms vs. 73 +/- 21 ms, P =.01) than those without AFib. Discriminant analysis revealed that only age, previous AFib and inta-atrial conduction delay (>90 ms) were independent predictors of postablation AFib. Patients without a history of AFib and with normal intra-atrial conduction had a 3% risk of AFib, while patients with both factors had a 90% risk of AFib after ablation. Intra-atrial conduction delay is an important electrophysiological factor predicting atrial fibrillation after successful flutter ablation.