Effects of Continuous Accelerated Pacing on Cardiac Structure and Function in Patients With Heart Failure With Preserved Ejection Fraction: Insights From the myPACE Randomized Clinical Trial.

BACKGROUND: Heart failure with preserved ejection fraction ≥50% is prevalent with few evidence-based therapies. In a trial of patients with heart failure with preserved ejection fraction with specialized pacemakers, treatment with accelerated personalized pacing averaging 75 bpm (myPACE) markedly improved quality of life, NT-proBNP (N-terminal pro-brain natriuretic peptide), physical activity, and atrial fibrillation burden compared with the standard lower rate setting of 60 bpm (usual care). METHODS AND RESULTS: In this exploratory study, provider-initiated echocardiographic studies obtained before and after the trial were assessed for changes in left ventricular (LV) structure and function among participants who continued their pacing assignment. The analytic approach aimed to detect differences in standard and advanced echocardiographic parameters within and between study arms. Of the 100 participants, 16 myPACE and 20 usual care arm had a qualifying set of echocardiograms performed a mean (SD) 3 (2.0) years apart. Despite similar baseline echocardiogram measures, sustained exposure to moderately accelerated pacing resulted in reduced septal wall thickness (in cm: myPACE 1.1 [0.2] versus usual care 1.2 [0.2], P=0.008) and lower LV mass to systolic volume ratio (in g/mL: myPACE 4.8 [1.9] versus usual care 6.8 [3.1], P=0.038) accompanied by a minor reduction in LV ejection fraction (in %: myPACE 55 [5] versus usual care 60 [5], P=0.015). These changes were paralleled by improvements in heart failure-related quality of life (myPACE Minnesota Living with Heart Failure Questionnaire improved by 16.1 [13.9] points, whereas usual care worsened by 6.9 [11.6] points, P<0.001). Markers of diastolic function and LV performance were not affected. CONCLUSIONS: Exposure to continuous accelerated pacing in heart failure with preserved ejection fraction is associated with a reduced LV wall thickness and a small amount of LV dilation with small reduction in ejection fraction.

Subclinical cardiac stiffness is associated with arterial stiffness in healthy young nulligravid women: Potential links to preeclampsia.

OBJECTIVES: Preeclampsia is an independent risk factor for subsequent cardiovascular disease and diastolic dysfunction and has been linked to arterial stiffness. We hypothesized that arterial stiffness would be associated with echocardiographic markers of diastolic dysfunction in healthy nulligravid women. STUDY DESIGN: 31 healthy nulligravid women underwent assessment of peripheral arterial stiffness via aorto-femoral pulse wave velocity, popliteal distensibility and ß stiffness measures as well as hemodynamic response to volume challenge. 22 underwent cardiac assessment via conventional and stress echocardiography with a focus on diastolic function utilizing tissue/pulse wave Doppler imaging and 3D speckle tracking. Bivariate associations between variables were evaluated using correlation coefficients (Pearson r) and Student's t-tests. RESULTS: No participants had echocardiographic values meeting criteria for overt diastolic dysfunction. Baseline global circumferential strain was significantly correlated with distensibility and ß stiffness (n = 18, r = -0.61, p = 0.007, n = 18, r = 0.56, p = 0.01). Peak deceleration time was correlated with ßstiffness (n = 9; r = 0.80, p = 0.01). Pulse wave velocity was not significantly correlated with cardiac measures (p > 0.05). Family history of a first or second degree relative with myocardial infarction or hypertension was associated with decreased popliteal artery distensibility (p = 0.02 and p = 0.03, respectively). CONCLUSIONS: In healthy nulligravid women there is evidence that markers of decreased left ventricular relaxation are associated with increased peripheral vascular stiffness as is a family history of myocardial infarction or hypertension. These findings raise the possibility that the diastolic dysfunction and arterial stiffness observed in the setting of preeclampsia are driven by underlying properties present prior to pregnancy and contribute to lifetime cardiovascular risk.

Cardiac Rehabilitation Participation Rates and Outcomes for Patients With Heart Failure.

PURPOSE: Exercise training has been shown to reduce combined cardiovascular mortality and hospitalizations in patients with chronic heart failure (CHF) with reduced ejection fraction (HFrEF). Whereas there are extensive data on exercise training for individuals with HFrEF in a research setting, the experience of delivering cardiac rehabilitation (CR) services in the clinical setting has not been well described. With little knowledge regarding the number of qualifying patients with HFrEF in the United States, we described our 18-month experience recruiting hospitalized inpatients and stable outpatients into phase 2 CR. METHODS: Patients hospitalized with CHF HFrEF were tracked for enrollment in CR. Exercise training response was described for patients identified as inpatients and for stable HFrEF outpatients referred from cardiology clinic or heart failure clinic. RESULTS: The cohort included 83 patients hospitalized with CHF and 36 outpatients. Only 17% (14/83) of eligible HFrEF inpatients enrolled in CR following CHF hospitalization compared with 97% (35/36) outpatient referrals. Improvements in aerobic capacity for the total cohort were observed whether expressed as estimated metabolic equivalents (n = 19, 4.6 ± 1.6 to 6.2 ± 2.4, P < .0001) or (Equation is included in full-text article.)O2peak (n = 14, 14.4 ± 3.5 to 16.4 ± 4.6 mL/kg/min, P = .02) for those who completed CR. CONCLUSION: Significant barriers to recruiting and enrolling patients with HFrEF were observed and only 17% of inpatients attended CR. Systematic in-hospital referral with close followup in the outpatient setting has the potential to capture more eligible patients. The participation of referred stable outpatients with HFrEF was much higher. Regardless of the referral source, patients with HFrEF completing CR can expect improvements in aerobic capacity, muscle strength, and depressive symptoms.