Optimization of the atrioventricular delay during cardiac resynchronization therapy using a device for non-invasive measurement of cardiac index at rest and during exercise.

AIMS: It is not clear whether cardiac resynchronization therapy (CRT) should only be optimized at rest or whether it is necessary to perform CRT optimization during exercise. Our study aims to answer this question by using an inert gas rebreathing method (Innocor®). METHODS AND RESULTS: Twenty-seven patients with congestive heart failure and implanted CRT devices were included in the study. The aetiology of the heart failure was ischaemic in nine (33%) patients. Patients had low left ventricular ejection fraction (29 ± 8%) and enlarged LV end-diastolic diameters (63 ± 7 mm). Atrioventricular delay (AVD) was optimized at rest according to cardiac index (CI), measured by inert gas rebreathing (Innocor®). Thereafter, patients performed standardized, steady-state bicycle exercise at 30 W in sitting body position. Three AVDs were tested during exercise in a random sequence: optimized resting AVD (AVD(opt)) according to baseline measurement; AVD(opt) - 30 ms; and AVD(opt) + 30 ms. Cardiac index was measured in each AVD by inert gas rebreathing. Cardiac index increased significantly during exercise. However, neither AVD(opt) shortening nor prolongation during exercise had significant effect on CI (shortening of AVD(opt) - 30 ms was accompanied by a reduction of CI of 4.8%, prolongation of AVD(opt) + 30 ms was accompanied by a reduction of CI of 7.7%). CONCLUSION: Shortening or lengthening of the AVD during exercise has no impact on CI in CRT patients. On the basis of our results, we conclude that in CRT patients the AVD should be programmed, fixed even during exercise.

Transesophageal left ventricular posterior wall potential in heart failure patients with biventricular pacing.

INTRODUCTION: Biventricular (BV) pacing is an established therapy for heart failure (HF) patients with intraventricular conduction delay, but not all patients improved clinically. We investigated the interventricular delay (IVD) by means of the transesophageal left ventricular posterior wall potential (LVPWP). MATERIALS AND METHODS, AND RESULTS: A total of 18 HF patients (age 62+/-9 years; 15 males) with NYHA class 3.1+/-0.3, LV ejection fraction 22+/-7%, left bundle branch block and a QRS duration (QRSD) of 171+/-27 ms were analyzed using transesophageal LVPWP before implantation of a BV pacing device. The median follow up was 14+/-14 months. In 14 responders, IVD was 81+/-25 ms with a QRSD/IVD ratio of 2.2+/-0.3 with reclassification of NYHA class 3.1+/-0.3 to 2.0+/-0.5 (p<0.001) and an increase in LV ejection fraction from 22+/-7% to 36+/-11% (p=0.001) during long-term BV pacing. In four non-responders, transesophageal IVD was significantly smaller at 30+/-11 ms (p=0.001). CONCLUSION: Transesophageal IVD may be a useful method to detect responders to BV pacing. Transesophageal LVPWP may be a simple and useful technique to detect clinical responders to BV pacing in HF patients.

Termination of atrial flutter by directed transesophageal atrial pacing during transesophageal echocardiography.

INTRODUCTION: The purpose of this study was to evaluate termination of atrial flutter (AFL) by directed rapid transesophageal atrial pacing (TAP) with and without simultaneous transesophageal echocardiography (TEE) performed using a novel TEE tube electrode. MATERIALS AND METHODS, AND RESULTS: A total of 16 AFL patients (age 63+/-12 years; 13 males) with mean AFL cycle length of 224+/-24 ms (n=12) and mean ventricular cycle length of 448+/-47 ms (n=12) were analyzed using either an esophageal TO electrode (n=10) or a novel TEE tube electrode consisting of a tube with four hemispherical electrodes that is pulled over the echo probe (n=6). AFL could be terminated by directed rapid TAP using an esophageal TO electrode, leading to induction of atrial fibrillation (AF) (n=6), induction of AF and spontaneous conversion to sinus rhythm (SR) (n=3), and with conversion to SR (n=1). AFL could also be terminated by directed rapid TAP using the TEE tube electrode, with induction of AF (n=3) or induction of AF and spontaneous conversion to SR (n=3). CONCLUSION: AFL can be terminated by directed rapid TAP with hemispherical electrodes with and without simultaneous TEE. TAP with the directed TEE tube electrode is a safe, simple, and useful method for terminating AFL.

Clinical AV nodal reentrant tachycardia in a patient with left sided accessory pathway and immediate occurrence of antidromic AV reentrant tachycardia after slow pathway ablation.

The only inducible arrhythmia in a patient with exclusive antegrade conducting left anterolateral accessory pathway, consists of slow/fast atrioventricular nodal reentrant tachycardia. After radiofrequency catheter ablation of the slow pathway, true antidromic AV reentrant tachycardia was easily induced by atrial pacing. Following ablation of the accessory pathway no arrhythmia could be induced.

Transesophageal left ventricular electrogram-recording and temporary pacing to improve patient selection for cardiac resynchronization.

Cardiac resynchronization therapy (CRT) with biventricular pacing (BV) is an established therapy for heart failure (HF) patients with inter- and intraventricular conduction delay. The aim of this pilot study was to test the feasibility of both transesophageal measurement of left ventricular (LV) electrical delay and transesophageal LV pacing prior to implantation, to better select patients for CRT. Esophageal TO8 Osypka catheter was perorally applied in 30 HF patients in position of maximum LV deflection to measure LV electrical delay and to study arterial pulse pressure (PP) during transesophageal bipolar LV pacing. There were 15 responders with a PP increase of a mean 65 ± 24 mmHg to 79 ± 27 mmHg (P < 0.001) and a mean LV electrical delay of 86.8 ± 33 ms. The 15 non-responders with poor PP increase of a mean 63.5 ± 23.5 mmHg to 64.1 ± 23.9 mmHg (P = 0.065) had a significantly smaller LV electrical delay of 36 ± 21 ms (P < 0.001). During a 34 ± 26 month CRT follow-up, the responders New York Heart Association (NYHA) class improved from 3.1 ± 0.35 to 2.1 ± 0.35 (P < 0.001). Determination of left ventricular electrical delay by transesophageal electrogram recording and transesophageal left ventricular pacing may be additional useful techniques to improve patient selection for CRT.

Left ventricular lead position and nonspecific conduction delay are predictors of mortality in patients during cardiac resynchronization therapy.

BACKGROUND: Cardiac resynchronization therapy (CRT) is an established treatment of severe systolic heart failure with intraventricular conduction delay. The influence on mortality of the left ventricular (LV) pacing site and the type of bundle-branch block during CRT is unclear. OBJECTIVES: This study investigates the clinical significance of LV lead position, as well as nonspecific conduction delay, in CRT. METHODS: 143 consecutive patients (mean age, 63.9 ± 8.9 years; 121 men) underwent implantation of a CRT device according to established criteria. At the time of implantation, the LV lead position and the type of bundle-branch block were recorded. The etiology of the heart failure was ischemic in 49 patients (34.3%) and nonischemic in 94 patients (65.7%). RESULTS: After a median follow-up of 19 months, 39 patients (27.3%) died, most of them (72%) of cardiovascular causes. The mortality was significantly higher in patients with an anterior or anterolateral LV lead position (P = 0.03). Multivariate analysis suggests that an anterior or anterolateral LV lead position, a nonspecific conduction delay, male sex, and a New York Heart Association functional class worse than III, are all independent predictors of mortality during the follow-up period. CONCLUSION: LV lead position and nonspecific conduction delay are predictors of mortality in patients during cardiac resynchronization therapy.

Transoesophageal left ventricular pacing in heart failure patients with permanent right ventricular pacing.

BACKGROUND: Previous studies of biventricular (BV) pacing for treatment of heart failure (HF) patients with left bundle branch block (LBBB) evaluated responders to BV pacing with acute transvenous left ventricular (LV) pacing and arterial pulse pressure (PP). The aim of this study was to assess transoesophageal LV pacing in evaluation of the haemodynamic response with a view to upgrading responders from permanent right ventricular (RV) pacing to BV pacing. METHODS AND RESULTS: Ten HF patients (age 62+/-8 years; one female, nine males) in NYHA III, LV ejection fraction 24+/-9% and permanent RV pacing by means of an implanted pacemaker or ICD were tested using transoesophageal LV pacing and PP. Permanently RV-paced HF patients were analysed with transoesophageal atrial sensed LV pacing in VAT mode with a different AV delay (n = 6) and with transoesophageal LV pacing in V00 mode during atrial fibrillation (n = 4). In five responders, PP was higher during transoesophageal LV pacing than PP during RV pacing (74+/-42 versus 57+/-31 mmHg, P = 0.015). Responders were upgraded by means of an LV lead via the coronary sinus in the posterior (n = 1) or posterolateral (n = 4) walls and after attaining a high LV pacing threshold with an epicardial LV lead on the anterior (n = 1) or anterolateral (n = 1) walls. NYHA class improved from 3 to 2+/-0.3 (P = 0.003) during 204+/-120 days follow-up and cardiac output increased from 4.4+/-1.5 to 5.6+/-1.7 l/min (P = 0.027) when comparing BV pacing and optimal AV delay with RV pacing. In five nonresponders, PP was not higher during transoesophageal LV pacing than during RV pacing. CONCLUSION: Transoesophageal LV pacing may be a useful technique to detect responders to BV pacing in permanently RV-paced HF patients.