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Introduction: Cardiac resynchronization therapy (CRT) with biventricular (BV) pacing is an established therapy for heart failure (HF) patients with ventricular desynchronization and reduced left ventricular (LV) ejection fraction. The aim of this study was to evaluate electrical ventricular desynchronization with transthoracic and transesophageal signal averaging electrocardiography in HF, to better select patients for CRT.
Methods: 13 HF patients (age 68 ± 10 years; 2 females, 11 males) with New York Heart Association (NYHA) class 2.8 ± 0.5, 28.6 ± 12.6 % LV ejection fraction and 155 ± 24 ms QRS duration (QRSD) were analysed with transthoracic and transesophageal electrocardiogram recording and novel National Intruments LabView 2009 signal averaging software. Esophageal TO Osypka catheter was perorally applied to the esophagus and placed in the position of maximum LV de-flection. The 0.05-Hz high-pass filtered surface electrocardiogram and the 10-Hz high-pass filtered bipolar transesophageal electrocardiogram were recorded with Bard EP-System and 1000-Hz sampling rate.
Results: Transesophageal LV electrogram recording was possible in all HF patients (n=13). Transesophageal interventricular conduction delay (IVCD) was 51 ± 19 ms and measured between the earliest onset of QRS in the 12-channel surface electrocardiogram and the onset of the LV deflection in the transesophageal electrocardiogram. Transesophageal intra-left ventricular delay (LVCD) was 90 ± 16 ms and measured between the onset and offset of the LV deflection in the transesophageal electrocardiogram. QRSD to transesophageal IVCD ratio was 3.43 ± 1.31 ms, QRSD to transesophageal LVCD ratio was 1.75 ± 0.28 ms and QRSD was evaluated between onset and offset of QRS signal in the 12-channel surface electrocardiogram.
Conclusion: Determination of IVCD, LVCD, QRSD-to-IVCD-ratio and QRSD-to-LVCD-ratio by transesophageal LV electrogram recording with LabView 2009 signal averaging technique may be useful parameters of ventricular desynchronisation to improve patient selection for CRT.
Background: R-wave synchronised atrial pacing is an effective temporary pacing
therapy in infants with postoperative junctional ectopic tachycardia. In the technique
currently used, adverse short or long intervals between atrial pacing and ventricular
sensing (AP–VS) may be observed during routine clinical practice.
Objectives: The aim of the study was to analyse outcomes of R-wave synchronised
atrial pacing and the relationship between maximum tracking rates and AP–VS
intervals.
Methods: Calculated AP–VS intervals were compared with those predicted by experienced
pediatric cardiologist.
Results: A maximum tracking rate (MTR) set 10 bpm higher than the heart rate (HR)
may result in undesirable short AP–VS intervals (minimum 83 ms). A MTR set 20 bpm
above the HR is the hemodynamically better choice (minimum 96 ms). Effects of either
setting on the AP–VS interval could not be predicted by experienced observers. In our
newly proposed technique the AP–VS interval approaches 95 ms for HR > 210 bpm
and 130 ms for HR < 130 bpm. The progression is linear and decreases strictly
(− 0.4 ms/bpm) between the two extreme levels.
Conclusions: Adjusting the AP–VS interval in the currently used technique is complex
and may imply unfavorable pacemaker settings. A new pacemaker design is advisable
to allow direct control of the AP–VS interval.
In cardiac resynchronization therapy (CRT) for heart failure, individualization of the AV delay is essential to improve hemodynamics and to minimize non-responder rate. In patients in sinus rhythm having additional disposition to bradycardia, optimization is necessary for both situations, atrial sensing and pacing. Therefore, echo-optimization is the goldstandard but time consuming. Unfortunately, it depends on the particular CRT systems parameter set if the resulting individually optimal AV delays can be programmed or not. Some CRT systems provide a set of AV delays for DDD operation combined with a set of the pace-sense-compensation to optimize the AV delay in DDD and VDD operation. The pace-sense-compensation (PSC) can be defined by the difference of implant-related interatrial conduction intervals in DDD and VDD operation measured in the esophageal left atrial electrogram. In a cohort of 96 CRT patients we found mean PSC of 59-35ms ranging between 0-143ms. As a consequence, allowing 10ms tolerance, AVD optimization is completely impossible in one of the two modes, VDD or DDD operation, in 34 (35%) or 5 (5%) patients with implants restricting the PSC range to 60ms or 100ms, respectively. Thus, we propose companies to provide CRT systems with programmable pace-sense- compensation between 0ms and 150ms.