Acute hemodynamic effects of a novel algorithm for cardiac resynchronization therapy optimization: Results from the BIO|Adapt study

Figures

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  Figure 1. Flowchart of the CRT AutoAdapt algorithm executed every 60 seconds. Adaptive AV delay is set to the smaller of (A–RV time minus 40 ms) or (A–RV time multiplied by 0.7), where 0.7 is a programmable factor in the range 0.5–0.9. A–RV and A–LV times are measured according to the patient’s current atrial rhythm, whether intrinsic or paced. If the atrial rhythm transitions between intrinsic and paced before the next measurement cycle, the algorithm uses the programmed sense compensation parameter (40 ms) to adjust the adaptive AV delay for the new rhythm type. No patient had both an atrial rate of >100 bpm and a PR interval of >250 ms. However, 4 patients had an atrial rate of >100 bpm, and 11 patients had a PR interval of >250 ms. A = atrial pacing or sensing; AV = atrioventricular; BiV pacing = simultaneous delivery of current to the RV and LV leads; bpm = beats/min; CRT = cardiac resynchronization therapy; LV = left ventricular; RV = right ventricular.

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  Figure 2. Comparison of cardiac performance between echocardiography-guided AV optimization (labeled “Echo”) and CRT AutoAdapt–optimized programming, in terms of AoVTI and LVEF measured by echocardiography before hospital discharge. Solid line: linear regression line. Dotted line: line of equality (slope = 1; intercept = 0). For an explanation of the AutoAdapt (0.7) and AutoAdapt (optimized or 0.7) datasets—labeled “AA (0.7)” and “AA (0.7 or opt)”—see the section “AutoAdapt (0.7) and AutoAdapt (optimized or 0.7) datasets” in Methods. AoVTI = aortic velocity time integral; AV = atrioventricular; CCC = concordance correlation coefficient (95% confidence interval); CRT = cardiac resynchronization therapy; LVEF = left ventricular ejection fraction.

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  Figure 3. Proportion of patients achieving the narrowest QRS width under each AV-delay programming method. The total percentage exceeds 100% because, in some patients, the narrowest QRS was achieved by more than 1 method. AV = atrioventricular; opt = optimized.