Case report of hidden (yet visible) systolic fascicular potentials in a patient with left bundle branch block during conduction system pacing implantation.

Background: Left bundle branch pacing (LBBP) is being increasingly adopted as a more physiological alternative to conventional pacing. At implantation, appropriate lead depth can be guided by monitoring a number of parameters, including the presence of a fascicular potential during conducted rhythm. However, in patients with left bundle branch block (LBBB), a presystolic fascicular potential is most often absent, due to upstream conduction block. We present for the first time a case where delayed fascicular potentials were visible within the ventricular electrogram (EGM) of the pacing lead. Case summary: An 88-year-old patient with decompensated heart failure of ischaemic origin with a left ventricular ejection fraction of 0.30 and LBBB with a QRS of 180 ms was scheduled for LBBP pacemaker implantation. A pacing lead was screwed deep into the interventricular septum in the left bundle branch area. Upon close inspection, fascicular potentials within the ventricular EGM were visible during cycles with LBBB. A presystolic fascicular potential was visible during cycles with a narrow QRS following blocked atrial premature beats with a pause. Threshold testing revealed transition from non-selective to selective LBBP, confirming conduction system capture. Discussion: The present case illustrates that fascicular potentials, which are most probably retrograde (or alternatively anterograde with very slow conduction), may be visualized within the ventricular EGM during LBBP implantation in patients with LBBB. Implanting physicians should scrutinize the EGM for these potentials, as they provide valuable information that adequate lead depth has been reached. The prevalence of these findings needs to be further evaluated.

Conduction System Pacing: Have We Finally Found the Holy Grail of Physiological Pacing?

The late fifties are considered a high point in the history of cardiac pacing, since this era is marked by the first pacemaker implantation, which has since evolved into life-saving therapy. Right ventricular apical and biventricular pacing are the classic techniques that are recommended as first-l ine approaches for most indications in current guidelines. However, conduction system pacing has emerged as being able to deliver a more physiological form of pacing and is becoming mainstream practice in a growing number of centres. In this review, we aim to compare traditional pacing methods with conduction system pacing.

Eight versus 28-point lung ultrasonography in moderate acute heart failure: a prospective comparative study.

Lung ultrasonography (LUS) is an accurate method of estimating lung congestion but there is ongoing debate on the optimal number of scanning points. The aim of the present study was to compare the reproducibility (i.e. interobserver agreement) and the feasibility (i.e. time consumption) of the two most practiced protocols in patients hospitalized for acute heart failure (AHF). This prospective trial compared 8- and 28-point LUS protocols. Both were performed by an expert-novice pair of sonographers at admission and after 4 to 6 days on patients admitted for AHF. A structured bio-clinical evaluation was simultaneously carried out by the treating physician. The primary outcome was expert-novice interobserver agreement estimated by kappa statistics. Secondary outcomes included time spent on image acquisition and interpretation. During the study period, 43 patients underwent a total of 319 LUS exams. Expert-novice interobserver agreement was moderate at admission and substantial at follow-up for 8-point protocol (weighted kappa of 0.54 and 0.62, respectively) with no significant difference for 28-point protocol (weighted kappa of 0.51 and 0.41; P value for comparison 0.74 at admission and 0.13 at follow-up). The 8-point protocol required significantly less time for image acquisition at admission (mean time difference - 3.6 min for experts, - 5.1 min for novices) and interpretation (- 6.0 min for experts and - 6.3 min for novices; P value < 0.001 for all time comparisons). Similar differences were observed at follow-up. In conclusion, an 8-point LUS protocol was shown to be timesaving with similar reproducibility when compared with a 28-point protocol. It should be preferred for evaluating lung congestion in AHF inpatients.

[Diagnosis of myocardial infarction in patients with cardiac pacing]. / Diagnostic d'un infarctuschez les patientsporteurs d'un stimulateur cardiaque.

Diagnosis of an acute coronary syndrome in patients with cardiac pacing can be difficult, as the usual ECG criteria for ischemia may not apply in case of a ventricular paced rhythm. This article discusses the ECG modifications observed in this setting, as well as in case of previous myocardial infarction. In addition, we discuss the phenomenon of cardiac memory, which may lead to erroneous diagnosis of myocardial ischemia.

Le diagnostic d'un syndrome coronarien aigu, sur la base de l'électrocardiogramme (ECG) chez les patients porteurs d'un stimulateur cardiaque, peut s'avérer particulièrement difficile. En effet, en raison des modifications électrocardiographiques présentes lors d'un rythme ventriculaire électro-entraîné, les critères de diagnostic habituels d'un infarctus aigu du myocarde ne s'appliquent pas. Cet article résume les critères actuellement proposés permettant d'établir ce diagnostic, ainsi que les signes ECG indiquant un ancien infarctus. Nous discutons également de la mémoire cardiaque, un phénomène à ne pas confondre avec un syndrome coronarien aigu.