Patrick Houthuizen

Left Bundle-Branch Block Induced by Transcatheter Aortic Valve Implantation Increases Risk of Death

Background— Transcatheter aortic valve implantation (TAVI) is a novel therapy for treatment of severe aortic stenosis. Although 30% to 50% of patients develop new left bundle-branch block (LBBB), its effect on clinical outcome is unclear. Methods and Results— Data were collected in a multicenter registry encompassing TAVI patients from 2005 until 2010. The all-cause mortality rate at follow-up was compared between patients who did and did not develop new LBBB. Of 679 patients analyzed, 387 (57.0%) underwent TAVI with the Medtronic CoreValve System and 292 (43.0%) with the Edwards SAPIEN valve. A total of 233 patients (34.3%) developed new LBBB. Median follow-up was 449.5 (interquartile range, 174–834) days in patients with and 450 (interquartile range, 253–725) days in patients without LBBB (P=0.90). All-cause mortality was 37.8% (n=88) in patients with LBBB and 24.0% (n=107) in patients without LBBB (P=0.002). By multivariate regression analysis, independent predictors of all-cause mortality were TAVI-induced LBBB (hazard ratio [HR], 1.54; confidence interval [CI], 1.12–2.10), chronic obstructive lung disease (HR, 1.56; CI, 1.15–2.10), female sex (HR, 1.39; CI, 1.04–1.85), left ventricular ejection fraction ⩽50% (HR, 1.38; CI, 1.02–1.86), and baseline creatinine (HR, 1.32; CI, 1.19–1.43). LBBB was more frequent after implantation of the Medtronic CoreValve System than after Edwards SAPIEN implantation (51.1% and 12.0%, respectively; P<0.001), but device type did not influence the mortality risk of TAVI-induced LBBB. Conclusions— All-cause mortality after TAVI is higher in patients who develop LBBB than in patients who do not. TAVI-induced LBBB is an independent predictor of mortality.

Baseline left ventricular dP/dtmax rather than the acute improvement in dP/dtmax predicts clinical outcome in patients with cardiac resynchronization therapy.

The maximum rate of left ventricular (LV) pressure rise (dP/dtmax) has been used to assess the acute haemodynamic effect of cardiac resynchronization therapy (CRT). We tested the hypothesis that LV dP/dtmax predicts long‐term clinical outcome after initiation of CRT.

Occurrence, fate and consequences of ventricular conduction abnormalities after transcatheter aortic valve implantation.

AIMS Transcatheter aortic valve implantation (TAVI) is frequently complicated by new left bundle branch block (LBBB). We investigated the development and persistence of LBBB during follow-up and its clinical consequences. METHODS AND RESULTS ECGs at baseline, within 24 hours, before discharge and at 12 months after TAVI were assessed in 476 patients without pre-existing LBBB and/or pacemaker before or after TAVI. TAVI-induced new LBBB was categorised based on the timing of the occurrence (within 24 hours [acute], after 24 hours but before discharge [subacute], and after discharge [late]), in addition to persistence (transient or persistent). A total of 175 patients (36.8%) developed new LBBB of which 85.7% occurred within 24 hours after TAVI, 12.0% before and 2.3% after hospital discharge, and was persistent in 111 patients (63.4%). Implantation of the Medtronic CoreValve System (MCS) more frequently led to new LBBB than the balloon-expandable Edwards SAPIEN valve (ES) (53.8% versus 21.7%) with less recovery during follow-up (39.0% versus 9.5%). Late new LBBB was only seen in four patients (0.8%). During a median follow-up of 915 (578-1,234) days, persistent LBBB was associated with a significant increase in mortality as compared to no LBBB and temporary LBBB combined (hazard ratio 1.49, 95% confidence interval, 1.10-2.03; p=0.01). CONCLUSIONS TAVI-induced new LBBB occurs in almost 40% of patients, almost all before hospital discharge. It occurs three times more frequently after MCS than after ES valve implantation and has a twofold lower tendency to resolve during follow-up. Persistent LBBB is associated with a higher mortality.

Transseptal left ventricular endocardial pacing: preliminary experience from a femoral approach with subclavian pull-through

AIMS Coronary sinus (CS) lead placement for transvenous cardiac resynchronization therapy (CRT) even combined with transseptal left ventricular (LV) endocardial implantation from a superior approach still does not have 100% success rate. The aim of this study was to assess the feasibility of a femoral transseptal endocardial LV approach pacing in patients in whom a transvenous CS or a transseptal LV endocardial implantation with a superior approach had failed. We report our first experience with LV endocardial lead placement for CRT with a femoral transseptal technique followed by intravascular pull-through to the pectoral location. METHODS AND RESULTS In 11 patients, 10 males (61.5 ± 9.5 years) with failed CS implant (four patients) or repeated CS lead malfunction (seven patients), a 4.1 French active fixation lead was implanted endocardially in the left ventricle employing a femoral approach using an 8F transseptal sheath combined with a hooked 6F catheter. After successful implantation, the lead was pulled through from the femoral insertion site to the pectoral device location. The LV endocardial implantation was successfully performed in all patients. Stimulation threshold was 0.62 ± 0.33 V, lead impedance 825 ± 127 Ω, and R wave 12.8 ± 8.3 mV. Threshold and lead impedance were stable during follow-up, which varied from 1 to 6 months. No dislodgements were observed and there were no thrombo-embolic events during follow-up. CONCLUSION This technique for LV endocardial lead implantation is an alternative for failed CS and superior transseptal attempts using standard techniques and equipment. It is also applicable for pacing sites that are more easily reached from a femoral approach.

Trends in the occurrence of new conduction abnormalities after transcatheter aortic valve implantation

The aim of the study was to investigate trends over time in the occurrence of left bundle branch block (LBBB) and permanent pacemaker implantation (PPI) after transcatheter aortic valve implantation (TAVI) with the Medtronic CoreValve System (MCS) and Edwards SAPIEN Valve (ESV). Background: TAVI‐induced conduction abnormalities (TAVI‐CAs) such as LBBB and the need for PPI are frequent postoperative complication. New techniques, procedural refinements, and increased awareness are focused on the reduction of these abnormalities.

Atrioventricular and interventricular delay optimization in cardiac resynchronization therapy: physiological principles and overview of available methods

In this review, the physiological rationale for atrioventricular and interventricular delay optimization of cardiac resynchronization therapy is discussed including the influence of exercise and long-term cardiac resynchronization therapy. The broad spectrum of both invasive and non-invasive optimization methods is reviewed with critical appraisal of the literature. Although the spectrum of both invasive and non-invasive optimization methods is broad, no single method can be recommend for standard practice as large-scale studies using hard endpoints are lacking. Current efforts mainly investigate optimization during resting conditions; however, there is a need to develop automated algorithms to implement dynamic optimization in order to adapt to physiological alterations during exercise and after anatomical remodeling.

Left ventricular endocardial pacing improves the clinical efficacy in a non-responder to cardiac resynchronization therapy: role of acute haemodynamic testing

Recently, emphasis has been shifted from patient selection to more optimal pacing sites in non-responders to cardiac resynchronization therapy (CRT). We present a patient who was a non-responder during both acute haemodynamic testing at implant as well as clinically thereafter. After first demonstrating acute haemodynamic improvement using LV d P /d t max during a temporary left ventricular (LV) endocardial pacing setup, a permanent LV endocardial lead was transseptally implanted with substantial and persistent clinical improvement.

Interplay of Electrical Wavefronts as Determinant of the Response to Cardiac Resynchronization Therapy in Dyssynchronous Canine Hearts

Background— The relative contribution of electromechanical synchronization and ventricular filling to the optimal hemodynamic effect in cardiac resynchronization therapy (CRT) during adjustment of stimulation-timings is incompletely understood. We investigated whether optimal hemodynamic effect in CRT requires collision of pacing-induced and intrinsic activation waves and optimal filling of the left ventricle (LV). Methods and Results— CRT was performed in dogs with chronic left bundle–branch block (n=8) or atrioventricular (AV) block (n=6) through atrial (A), right ventricular (RV) apex, and LV-basolateral pacing. A 100 randomized combinations of A-LV/A-RV intervals were tested. Total activation time (TAT) was calculated from >100 contact mapping electrodes. Mechanical interventricular dyssynchrony was determined as the time delay between upslopes of LV and RV pressure curves. Settings providing an increase in LVdP/dtmax (maximal rate of rise of left ventricular pressure) of ≥90% of the maximum LVdP/dtmax value were defined as optimal (CRTopt). Filling was assessed by changes in LV end-diastolic volume (EDV; conductance catheter technique). In all hearts, CRTopt was observed during multiple settings, providing an average LVdP/dtmax increase of ≈15%. In AV-block hearts, CRTopt exclusively depended on interventricular-interval and not on AV-interval. In left bundle–branch block hearts, CRTopt occurred at A-LV intervals that allowed fusion of LV-pacing–derived activation with right bundle–derived activation. In all animals, CRTopt occurred at settings resulting in the largest decrease in TAT and mechanical interventricular dyssynchrony, whereas LV EDV hardly changed. Conclusions— In left bundle–branch block and AV-block hearts, optimal hemodynamic effect of CRT depends on optimal interplay between pacing-induced and intrinsic activation waves and the corresponding mechanical resynchronization rather than filling.

The Interplay of Electrical Wave Fronts as Determinant of the Response to Cardiac Resynchronization Therapy in Dyssynchronous Canine Hearts

Background— The relative contribution of electromechanical synchronization and ventricular filling to the optimal hemodynamic effect in cardiac resynchronization therapy (CRT) during adjustment of stimulation-timings is incompletely understood. We investigated whether optimal hemodynamic effect in CRT requires collision of pacing-induced and intrinsic activation waves and optimal filling of the left ventricle (LV). Methods and Results— CRT was performed in dogs with chronic left bundle–branch block (n=8) or atrioventricular (AV) block (n=6) through atrial (A), right ventricular (RV) apex, and LV-basolateral pacing. A 100 randomized combinations of A-LV/A-RV intervals were tested. Total activation time (TAT) was calculated from >100 contact mapping electrodes. Mechanical interventricular dyssynchrony was determined as the time delay between upslopes of LV and RV pressure curves. Settings providing an increase in LVdP/dtmax (maximal rate of rise of left ventricular pressure) of ≥90% of the maximum LVdP/dtmax value were defined as optimal (CRTopt). Filling was assessed by changes in LV end-diastolic volume (EDV; conductance catheter technique). In all hearts, CRTopt was observed during multiple settings, providing an average LVdP/dtmax increase of ≈15%. In AV-block hearts, CRTopt exclusively depended on interventricular-interval and not on AV-interval. In left bundle–branch block hearts, CRTopt occurred at A-LV intervals that allowed fusion of LV-pacing–derived activation with right bundle–derived activation. In all animals, CRTopt occurred at settings resulting in the largest decrease in TAT and mechanical interventricular dyssynchrony, whereas LV EDV hardly changed. Conclusions— In left bundle–branch block and AV-block hearts, optimal hemodynamic effect of CRT depends on optimal interplay between pacing-induced and intrinsic activation waves and the corresponding mechanical resynchronization rather than filling.

Clinical Implications of Conduction Abnormalities and Arrhythmias After Transcatheter Aortic Valve Implantation

Transcatheter aortic valve implantation (TAVI) has become an established treatment option for patients with aortic stenosis at prohibitive risk to undergo surgical aortic valve replacement. Despite conveying obvious clinical benefits and a decreasing frequency of complications, the occurrence of new conduction abnormalities and arrhythmias remains an important issue. Generally considered a minor complication, they may have a profound impact on prognosis and quality of life after TAVI. Therefore the purpose of this review is to assess and discuss the available information on clinical implications of both new conduction abnormalities and arrhythmias after TAVI.