Atrial Dysfunction, Pacemaker Ddd Permanent, Quality of Life
Conditions
Keywords
AV optimization, Interatrial conduction delay
Brief summary
Though AV optimization has become a cornerstone in optimization of patients with a cardiac resynchronization therapy (CRT) device, surprisingly the use of AV optimization in patients with a dual chamber (bicameral (BIC)) pacemaker is not fully implemented in daily clinical practice. Some patients with a BIC pacemaker have a too short AV delay (AVD), secondary to an important interatrial conduction delay (IACD), which can lead to an atrial dyssynchrony syndrome. Others have a too long AV delay, also leading to a suboptimal diastolic filling time. Some patients may not need an optimization. Our aim was to evaluate the effect of AV optimization in all comer ambulatory patients with a BIC pacemaker on clinical outcomes, with a correlation to atrial pathophysiology, since until now existing evidence only emphasizes a possible hemodynamic benefit of this non invasive intervention.
Detailed description
Given the high prevalence of interatrial block (WHO definition: PWD on surface ECG \> 110 ms) in a general hospitalized population and especially in patient groups with tachyarrhythmias (18% and 52 % respectively), this phenomenon will be important to recognize in a BIC pacemaker patient population. Actually, the prevalence of advanced interatrial block (PWD \> 120 ms with biphasic P wave morphology) is 10% in candidates for definitive pacing and 32 % in patients with a bradycardia-tachycardia syndrome. The main underlying mechanism is thought to lie in abnormalities of the Bachmann bundle resulting in partial or advanced interatrial conduction delay (IACD). A normal IACD varies between 60 and 85 ms. Two potential mechanisms are spatial dispersion of refractory periods or anisotropy resulting from scarce side-to-side electrical coupling and fibrosis disrupting the arrangement of atrial muscle fibers. Patients with an interatrial conduction delay may have a suboptimal left atrioventricular timing due to delayed contraction of the left atrium with foreshortening of ventricular filling. This may be an issue in pacemaker patients, with our without a substrate for heart failure. Beside the loss of reduction of left atrial contraction, it might even induce neurohormonal changes due to atrial stretch and pressure thus lowering blood pressure. Coronary sinus or multisite atrial pacing, both with the aim of synchronizing right and left atrial electrical activation, have shown to (i) improve hemodynamics in patients with an important IACD, both invasively and noninvasively, and to (ii) decrease recurrences of atrial fibrillation. In patients with a conventional BIC pacemaker, prevention of left atrioventricular asynchrony can be achieved by AV optimization (lengthening of the AV delay in case of too short nominal settings) as an alternative. Though all these interventions have proven to have positive hemodynamic results until now evidence about positive effects on clinical patient outcomes are lacking. On the other hand, some of the patients implanted with a bicameral pacemaker have a too long AV delay. As a consequence diastolic filling time is impaired. Without compromising left atrioventricular synchrony AV delay, optimal AVD (AVO) can be achieved by lengthening of the AVD with conventional methods. In contrast to the setting of CRT, AV optimization in patients with a bicameral (BIC) pacemaker is not fully implemented in daily clinical practice. Given the proven effect on mitral inflow on echocardiography, we wanted to evaluate the effect of this non invasive intervention on patient functionality and quality of life, based on a comprehensive assessment of atrial pathophysiology.
Interventions
DEVICEAV optimization
Iterative DFT (diastolic filling time) method for AV optimization. Optimal AV delay for both atrial sensed and atrial paced settings was defined by two experienced echocardiographists, after 3 separate measurements.
Sponsors
Jessa Hospital
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
TREATMENT
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Ambulatory all comer patient population at least 3 months after implantation of a dual chamber pacemaker * Programmed in a DDD(R) modus * Right ventricular pacing percentage of \> 50%
Exclusion criteria
* permanent atrial fibrillation * endstage chronic obstructive lung disease * severe psychiatric, orthopedic or neurological comorbidity * acute illness at the moment of inclusion * changes in cardiovascular medication the month before inclusion until the end of the study protocol
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in exercise capacity, expressed by oxygen uptake efficiency slope | baseline, 4 weeks, 8 weeks | Ergospirometry protocol: Symptom-limited exercise testing was performed on an electronically braked cycle ergometer (eBike 1.8, GE (General Electric) Healthcare) in a non-fasting condition and under medication. All exercise tests took place at a standardized time for each patient. After 1minute (min) of rest followed by 1min of unloaded cycling, the initial load was set at 20W (Watt) for 1 min, and was increased by 10 or 20W every 2 min until exhaustion. Cycle load increments were based on previous exercise testing, aiming to yield a test duration of approximately 10min. All tests were continued to volitional fatigue and no patients were limited by angina. The recovery period lasted at least 2 minutes. A 12-lead electrocardiogram was monitored continuously (Cardiosoft 6.6); maximum heart rate was registered. The oxygen uptake efficiency slope (OUES) was calculated using \[VO2= m(log10VE)+b, where m= OUES\]. VO2=oxygen consumption |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in left atrial function, measured by left atrial late diastolic peak strain (εm) | baseline, 4 weeks, 8 weeks | — |
| Change in left atrial function, measured by left atrial late diastolic peak strain rate (SRm) | baseline, 4 weeks, 8 weeks | — |
| Change in systolic pulmonary artery pressure (PAPs) | baseline, 4 weeks, 8 weeks | — |
| Change in NYHA class: New York Heart Association Class | baseline, 4 weeks, 8 weeks | — |
| Change in quality of life | baseline, 4 weeks, 8 weeks | Quality of life, measured by a standardized Heart Qol questionnaire |
| Change in 6-Minute Walk test Distance (6MWD) | baseline, 4 weeks, 8 weeks | — |
| Change in serum brain natriuretic peptide (BNP) | 4 weeks, 8 weeks | — |
| Change in left atrial function, measured by left mitral annular late diastolic peak velocity (A'm(c)) | baseline, 4 weeks, 8 weeks | — |
| Change in exercise capacity, expressed by VO2max (maximal oxygen consumption) | baseline, 4 weeks, 8 weeks | cf. Ergospirometry protocol |
Other
| Measure | Time frame | Description |
|---|---|---|
| Correlation between atrial pacing frequency and duration of the IACD | baseline | All measurements were done in sinus rhythm and during atrial pacing. IACD (and left atrial function) was also measured for each patient at an atrial pacing frequency of 75 ppm (at the time of AVD optimization). |
| Correlation between atrial pacing frequency and left atrial function (measured by left mitral annular late diastolic peak velocity (A'm(c)). | 4 weeks | All measurements were done in sinus rhythm and during atrial pacing. IACD (and left atrial function) was also measured for each patient at an atrial pacing frequency of 75 ppm (at the time of AVD optimization). |
| Correlation between IACD and pacing indication | baseline | Hypothesis: AV block indication might have smaller IACD compared to bradycardia tachycardia syndrome indication, since in the latter one might consider more elaborate atrial pathology. |
| Correlation between IACD and the length of the optimal AV delay. | baseline, 4 weeks | Hypothesis: the larger the IACD, the more the AV delay should be lengthened to optimize mitral inflow. |
| Correlation between 3 distinct measurements of interatrial conduction delay (IACD) | baseline | IACD¹ is defined as the time interval from the onset of the P wave on the ECG to the onset of the mitral peak late (A) velocity. IACD² is defined as the time interval from the onset of the P wave on the ECG to the onset of A'm (with A'm representing late diastolic myocardial velocity at the lateral mitral annulus level). IACD³ is defined as the time interval from the onset of the P wave on the ECG to the onset of A'm(c)(with A'm(c) representing the annular late diastolic peak velocities lateral mitral annular level). |
| Prevalence of interatrial conduction delay (IACD) in the study population | baseline | IACD is defined as the time interval from the onset of the P wave on the ECG to the onset of A'm(c)(with A'm(c) representing the annular late diastolic peak velocities lateral mitral annular level). IACD measured this way in the study is called IACD³. |
| Correlation of IACD with age | baseline | Hypothesis: interatrial conduction time will be higher in an elderly population |
| Correlation of IACD with P Wave Duration (PWD) | baseline | All standard 12-lead ECGs were obtained using the same recorder (Schiller, CARDIOVIT AT-10 plus) set at a 50 mm/s paper speed and 2 mV (millivolt)/cm standardization. To decrease the error, we measured P-wave duration manually with calipers. The mean P-wave duration (PWD) of 3 complexes was calculated in lead II. A PWD of \> 120 ms, with or without a biphid P wave morphology was considered to be pathological and used for correlation study with IACD. |
| Correlation of IACD with left atrial function | 4 weeks | Components of left atrial function, as mentioned in secondary outcomes measures, namely left mitral annular late diastolic peak velocity (A'm(c)), left atrial late diastolic peak strain (εm), left atrial late diastolic peak strain rate (SRm). Hypothesis: the larger the IACD, the poorer the left atrial function. |
| Correlation of change in VTI(A) (velocity-time integral) after AV optimization with clinical response (measured by OUES) after AV optimization | baseline, 4 weeks, 8 weeks | Hypothesis: change in VTI of the A wave on mitral inflow on echocardiography is a predictor of clinical response after AV optimization. |
| Correlation of change in mitral annular late diastolic peak velocity (A'm(c)) after AV optimization with clinical response (OUES) after optimization. | baseline, 4 weeks, 8 weeks | Hypothesis:change in mitral annular late diastolic peak velocity (A'm(c)) after AV optimization on echocardiography is a predictor of clinical response after AV optimization. |
| Prevalence of right and left intraatrial asynchrony. | baseline | Intra-atrial asynchrony was defined as the differences between EMD(electromechanical delay)s'(c) and EMDt'(c) (RA asynchrony) and between EMDm'(c) and EMDs'(c) (LA asynchrony). EMDm'(c) is defined as the time interval from the onset of the P wave on the ECG to the onset of A'm(c). EMDt'(c) is defined as the time interval from the onset of the P wave on the ECG to the onset of A't(c). EMDs'(c) is defined as the time interval from the onset of the P wave on the ECG to the onset of A's(c). A't(c), A's(c) and A'm(c) are defined as the annular late diastolic peak velocities at lateral tricuspid, interatrial and lateral mitral annular level. |
| Role of P sense offset in IACD (interatrial conduction delay) | baseline | Hypothesis: the larger the IACD, the larger the P sense offset (time from P-onset to P-detection). |
| Change of the incidence of atrial fibrillation on a short term after rigourous AV optimization | baseline, 4 weeks, 8 weeks | — |
Countries
Belgium
Outcome results
None listed