Gustafsson, Finn

Abstract Background Patient-worn accelerometer is increasingly used in patients with heart failure and reduced ejection fraction (HFrEF) to assess daily activity and and as surrogate endpoint. We examined the association between cardiac physiology and daily activity by patient-worn accelerometer recordings in stable HFrEF patients. Methods In this descriptive study, physical average daily accelerometer units (PADA) and total average daily accelerometer unit (TADA) were assessed by a accelerometer recordings. Sixty three stable ambulatory patients with HFrEF, mainly men (92%), mean age 58±10 years, and ejection-fraction 26±4% underwent hemodynamic exercise testing, and accelerometry (Table 1). Patients were divided by PADA in a low and high activity level groups based on counts per minute physical activity. Results Patients in the low activity group were older and more frequently treated with diuretics. At rest, the low activity group was characterized by a lower cardiac index (CI) (2.2±0.4 vs. 2.4±0.4 l/min/m2, p=0.01), Stroke volume (SV) (70±19 vs. 81±17 ml, p=0.02) but not pulmonary capillary wedge pressure (PCWP) (12±5 vs. 11±5 mmHg, p=0.3) (Figure 1). Low activity group reached a lower CI (4.8±1.7 vs. 6.6±1.7 l/min/m2, p<0.001) and SV (94±32 vs. 121±29 ml, p<0.001), but not in PCWP (31±12 vs. 27±8 mmHg, p=0.2) or arterial-venous O2 content difference (A-VO2 diff) (13.00±2.32 vs. 12.96±1.65 ml O2/dl, p=0.9) at peak exercise. The attenuated increase was associated with attenuated increase in SV rther than increase in heart rate (42±23 vs. 52±21 bpm, p=0.07). Finally, CI at peak exercise was the only independent variable associated with PADA after adjusting for age, gender, and BMI (p<0.0001). The PADA and TADA were associated to functional assessments using Kansas City Cardiomyopathy Questionnaire, but not with New York Heart Association class or N-terminal pro brain natriuretic peptide (NT-proBNP) (Table 1). Conclusion Accelerometer-assessed activity in patients with HFrEF are associated with impairments in LV performance, SV reserve and cardiac output during exercise, to a greater extent than changes in arterial-venous O2 content difference or pulmonary vascular pressures. Accelerometer data may provide information about the functional status that we do not nessecary find in the widely used tools in both research and daily clinical practice. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): This work was supported by the Danish Heart Foundation [grant numbers 17-R116-A7714-22076, 18-R124-A8573-22107]; Steno Diabetes Center Odense, Denmark [grant number 3363] and A.P. Møller Foundation for the Advancement of Medical Science [grant number 17-L-0339]. Table 1. Baseline and regression analysisFigure 1. Change in PCWP and CI by exercise

Abstract Aims A hallmark of heart failure with preserved ejection fraction (HFpEF) is impaired exercise capacity of varying severity. The main determinant of exercise capacity is cardiac output (CO), however little information is available about the relation between the constituents of CO – heart rate and stroke volume – and exercise capacity in HFpEF. We sought to determine if a heterogeneity in heart rate and stroke volume response to exercise exists in patients with HFpEF and describe possible clinical phenotypes associated with differences in these responses. Methods and results Data from two prospective trials of HFpEF ( n = 108) and a study of healthy participants ( n = 42) with invasive haemodynamic measurements during exercise were utilized. Differences in central haemodynamic responses were analysed with regression models. Chronotropic incompetence was present in 39–56% of patients with HFpEF and 3–56% of healthy participants depending on the definition used, but some ( n = 47, 44%) had an increase in heart rate similar to that of healthy controls. Patients with HFpEF had a smaller increase in their stroke volume index (SVI) (HFpEF: +4 ± 10 mL/m 2 , healthy participants: +24 ± 12 mL/m 2 , P < 0.0001), indeed, SVI fell in 28% of patients at peak exercise. Higher body mass index and lower SVI at rest were associated with smaller increases in heart rate during exercise, whereas higher resting heart rate, and angiotensin‐converting enzyme inhibitor/angiotensin II receptor blocker use were associated with a greater increase in SVI in patients with HFpEF. Conclusion The haemodynamic response to exercise was very heterogeneous among patients with HFpEF, with chronotropic incompetence observed in up to 56%, and 28% had impaired increase in SVI. This suggests that haemodynamic exercise testing may be useful to identify which HFpEF patients may benefit from interventions targeting stroke volume and chronotropic response.

Approximately 50% of patients with heart failure have preserved ejection fraction. Although a wide variety of conditions cause or contribute to heart failure with preserved ejection fraction, elevated left ventricular filling pressures, particularly during exercise, are common to all causes. Acute elevation in left‐sided filling pressures promotes lung congestion and symptoms of dyspnea, while chronic elevations often lead to pulmonary vascular remodeling, right heart failure, and increased risk of mortality. Pharmacologic therapies, including neurohormonal modulation and drugs that modify the nitric oxide/cyclic GMP‐protein kinase G pathway have thus far been limited in reducing symptoms or improving outcomes in patients with heart failure with preserved ejection fraction. Hence, alternative means of reducing the detrimental rise in left‐sided heart pressures are being explored. One proposed method of achieving this is to create an interatrial shunt, thus unloading the left heart at rest and during exercise. Currently available studies have shown 3‐ to 5‐mm Hg decreases of pulmonary capillary wedge pressure during exercise despite increased workload. The mechanisms underlying the hemodynamic changes are just starting to be understood. In this review we summarize results of recent studies aimed at elucidating the potential mechanisms of improved hemodynamics during exercise tolerance following interatrial shunt implantation and the current interatrial shunt devices under investigation.

Background Interatrial shunt device (IASD) effects have been described in patients with heart failure and ejection fractions (EFs) ≥40%. However, baseline characteristics that correlate with greatest hemodynamic effects are unknown. On the basis of fundamental principles, we hypothesized that larger pressure gradients between left and right atria would yield greater shunt flow and greater hemodynamic effects. Methods and Results REDUCE LAP-HF (Reduce Elevated Left Atrial Pressure in Patients With Heart Failure) was a multicenter study that investigated IASD safety and performance. Sixty-four patients with EF ≥40% underwent device implantation followed by hemodynamic assessments at rest and exercise, including pulmonary capillary wedge pressure (PCWP, surrogate for left atrial pressure) and central venous pressure (CVP). At 6 months, IASD resulted in an average pulmonary-to-systemic blood flow ratio of 1.27 and increased exercise tolerance. The PCWP-CVP gradient (ie, the driving pressure for shunt flow) decreased at peak exercise from 16.8±6.9 to 11.4±5.5 mm Hg, because of increased CVP (17.5±5.4 to 20.3±7.9 mm Hg; P =0.04) and decreased PCWP (34.1±7.6 to 31.6±8.0 mm Hg; P =0.025). Baseline PCWP-CVP gradient during exercise correlated with changes of both PCWP-CVP and PCWP: Δ(PCWP-CVP)=10.0−0.89·(PCWP-CVP) baseline ( r 2 =0.56) and ΔPCWP=7.54−0.60·(PCWP-CVP) baseline ( P =0.001). Hemodynamics of patients with EF ≥50% and those with EF <50% responded similarly to IASD. Conclusions In heart failure patients with EF ≥40%, IASD significantly reduced PCWP and PCWP-CVP at peak exercise. Patients with higher baseline PCWP-CVP gradient had greater reductions in both parameters at follow-up. Results were sustained through 12 months and were independent of whether EF was ≥50% or between 40% and 49%. Additional studies will help further define the baseline hemodynamic predictors of exercise, hemodynamic, and clinical efficacy of the IASD. Clinical Trial Registration URL: https://www.clinicaltrials.gov . Unique identifier: NCT01913613.

Abstract Aims Patients with heart failure and preserved ejection fraction (HFpEF) are characterized by functional impairment and an abnormal haemodynamic response to exercise. The six-minute walk test (6MWT) serves as a standardized test for functional capacity quantification in heart failure patients, and is associated with cardiovascular outcomes. However, as the association between 6MWT and haemodynamic parameters during rest and exercise in HFpEF patients is unknown, we sought to elucidate this relationship. Methods and results Overall, 64 patients enrolled in the REDUCE LAP-HF trial completed a 6MWT at baseline. Univariate and multivariable linear regression models were used to assess the associations between 6MWT and measured or derived haemodynamic variables at baseline, during light/moderate exercise (20 W), and at peak supine exercise. The average 6MWT distance was 318 ± 106 m. At rest, in a multivariable model, only pulmonary capillary wedge pressure (PCWP) was significantly associated with 6MWT [coefficient: –5.4, 95% confidence interval (CI) –10.4, –0.5, P = 0.033]. During light/moderate exercise, mean pulmonary artery pressure was associated with 6MWT in a multivariable model (coefficient: –3.5, 95% CI –6.8, –0.3, P = 0.033). During peak exercise, central venous pressure, cardiac index (CI), and PCWP/CI correlated with 6MWT; however, workload corrected PCWP was the only variable independently associated with 6MWT (coefficient: –0.8, 95% CI –1.3, –0.4, P &lt; 0.001). The variance in 6MWT was modestly explained by measured or derived haemodynamic variables at rest or at any stage of exercise (r2 = 7–17%). Conclusion Workload corrected PCWP correlated best with 6MWT performance in HFpEF patients. Baseline haemodynamic variables were modestly correlated with 6MWT, suggesting that 6MWT performance in HFpEF patients may be significantly influenced by extra-cardiac factors.

Background— Diastolic dysfunction is frequently seen after myocardial infarction and is characterized by a disproportionate increase in filling pressure during exercise to maintain stroke volume. We hypothesized that sildenafil would reduce filling pressure during exercise in patients with diastolic dysfunction after myocardial infarction. Methods and Results— Seventy patients with diastolic dysfunction and near normal left ventricular ejection fraction on echocardiography were randomly assigned sildenafil 40 mg thrice daily or matching placebo for 9 weeks. Before randomization and after 9 weeks of treatment patients underwent simultaneous echocardiography and right heart catheterization at rest and during exercise. Primary end point was pulmonary capillary wedge pressure, and secondary end points comprised cardiac index and pulmonary arterial pressure at rest and during exercise after 9 weeks. After 9 weeks there were no differences in pulmonary capillary wedge pressure at rest (13±4 versus 13±3 mm Hg, P =0.25) or at peak exercise (35±8 mm Hg versus 31±7 mm Hg, P =0.07). However, with treatment cardiac index increased at rest ( P =0.006) and peak exercise ( P =0.02) in the sildenafil group, and systemic vascular resistance index (resting, P =0.0002; peak exercise, P =0.007) and diastolic blood pressure (resting, P =0.005; peak exercise, P =0.02) were lower in the sildenafil group. Resting left ventricular end-diastolic volume index increased ( P =0.001) within the sildenafil group but was unchanged in the placebo group. Conclusions— Sildenafil did not decrease filling pressure at rest or during exercise in post–myocardial infarction patients with diastolic dysfunction. However, there were effects on secondary end points, which require further studies. Clinical Trial Registration— URL: http://www.clinicaltrials.gov/ct2/show/NCT01046838 . Unique identifier: NCT01046838.

Background— Left ventricular diastolic dysfunction (DD) is common after myocardial infarction (MI) despite preservation of left ventricular ejection fraction, yet it remains unclear how or whether DD affects cardiac hemodynamics with stress. Methods and Results— Invasive hemodynamic exercise testing was performed in 46 patients with a recent MI and left ventricular ejection fraction >45% and in 10 healthy volunteers. MI patients were enrolled prospectively and divided into those with DD (MI+DD; left atrial volume index >34 mL/m 2 and diastolic E/e′ ratio>8; n=35) and those without DD (MI–DD; left atrial volume index <34 mL/m 2 and E/e′ ratio<8; n=11). All underwent a supine cycle ergometer test with simultaneous right heart catheterization and echocardiography. At rest, 10 patients in MI+DD (29%) had pulmonary capillary wedge pressure >15 (14±4 mm Hg), whereas none of the MI−DD (10±2 mm Hg) or controls (9±2 mm Hg) displayed pulmonary capillary wedge pressure elevation ( P =0.03). During exercise, an abnormal rise in pulmonary capillary wedge pressure (>25 mm Hg) was observed in 94% of MI+DD (36±6 mm Hg) compared with 36% of MI−DD (24±6 mm Hg) and none of the controls (16±6 mm Hg; P <0.0001). Exercise right atrial pressure was the highest in MI+DD followed by MI−DD and control (15±5 versus 9±4 versus 7±5 mm Hg; P <0.001), whereas no difference in cardiac index was found between groups. Conclusions— In post-MI patients with preserved ejection fraction and left ventricular DD, cardiac output with exercise is maintained at the expense of substantially increased filling pressure. DD and loss of diastolic reserve may promote progression from stage B to stage C heart failure after MI. (Circ Heart Fail. 2012;5:-451.)