Shah, Sanjiv J

PR interval (PR) prolongation is a predictor of atrial fibrillation, a common cardiac arrhythmia, and is an established risk factor for pacemaker implantation, heart failure, stroke, and all-cause mortality. Previous genome-wide association studies in European (EU) and African (AA) descent populations have identified multiple loci associated with PR. However, it is unclear whether these loci are relevant in other racial groups, including Hispanic/Latinos (HL). Extending studies to include admixed populations such as HL also provides the potential to narrow regions associated with PR and identify population specific variants. Therefore, we evaluated 1,135 SNPs from four previously identified PR loci ( SCN5A, SCN10A, CAV1-CAV2, and TBX5-TBX3 ), fine-mapped on the Illumina Metabochip for association with PR. Associations were examined using linear regression assuming an additive genetic model and adjusting for global ancestry and clinical covariates (age, sex, RR interval, body mass index, height, systolic blood pressure) in 11,800 HL participants from participating studies of the Population Architecture using Genomics and Epidemiology (PAGE) consortia. Three of the four loci ( SCN5A, SCN10A, and CAV1-CAV2 ) generalized to HL populations ( P <7.1E-4 based on the number of SNPs correlated at r 2 >0.2 with EU-identified index SNPs). At each of these loci, we identified SNPs with stronger evidence of association with PR than the EU-identified index SNP when examined in the HL population ( SCN5A : rs7374540; SCN10A : rs6801957; CAV-CAV2 : rs717957). Conditional analyses also identified two additional independent SNPs at each of the three generalized loci ( SCN5A : rs3796387, rs9861242; SCN10A : rs10428132, rs7433723; CAV1-CAV2 : rs3801995, rs3807994), representing potential secondary signals. Furthermore, linkage disequilibrium (LD) patterns in Hispanics enabled the narrowing of the regions flanking the EU-identified index SNPs. For example, at the CAV1-CAV2 locus, HL LD patterns indicated that seven SNPs were in LD with rs3807989, the EU-identified index SNP, compared to 17 SNPs that were in LD with rs3807989 when applying EU LD patterns, reducing the size of the region by 71 kilobases. Finally, we examined evidence for population specific signals outside of the specific regions identified in EU populations which were associated with PR in Hispanics by focusing on SNPs uncorrelated with the EU index signals. At all four loci, multiple SNPs had evidence of association independent of the signals examined based on EU results. In conclusion, the same genetic loci that influence PR in European descent populations are also important in Hispanic populations, although we detected evidence for population specific SNPs. These results emphasize the importance of examining genetic associations in diverse populations in order to narrow the genomic interval for future functional interrogation.

Background: There are no specific treatments for patients with HFpEF and pulmonary hypertension (PH-HFpEF). Increased central and pulmonary venous pressures (CVP, PCWP) are believed to contribute importantly to symptoms at rest and during exercise. Levosimendan (LEVO), a calcium sensitizer/KATP channel activator, is known to reduce CVP and PCWP in patients with reduced LVEF. We hypothesized that LEVO would have similar effects in PH-HFpEF. Methods: 44 PH-HFpEF patients with mean pulmonary artery (mPAP) ≥35 mmHg, PCWP ≥20 mmHg, LVEF ≥40% and NYHA II or III symptoms underwent hemodynamic measurements at rest, during passive leg raise (PLR) and during supine bicycle exercise for 3 minutes at 25 Watts (EX) at baseline and following a continuous 24-hour infusion of LEVO (0.1 μg/kg/min) as part of a multicenter clinical trial. Measurements included CVP, mPAP, PCWP, mean arterial pressure (MAP) and cardiac index (CI); pulmonary and systemic vascular resistances (PVR, SVR) were calculated. Hemodynamic tracings were analyzed in a core lab blinded to condition and timepoint. The primary endpoint was the change of PCWP at 25 Watts. Results: Patients averaged 69±9.1 years old, 61.4% were female and had a mPAP of 41.0±9.3 mmHg at rest. LEVO decreased mPAP at rest, CVP and PCWP at rest and EX, and increased CI with EX; there were no significant changes in mPAP, PVR or SVR. Resting and EX hemodynamic data are summarized in the Table. 37 of the 44 patients (84%) were considered hemodynamic “responders” based on a pre-specified ≥4 mmHg decrease of EX PCWP. Conclusions: In patients with PH-HFpEF, a 24 hour levosimendan infusion at 0.1 μg/kg/min decreased CVP and PCWP and increased CI at rest and EX, despite no significant effect on SVR or PVR. A majority of patients exhibited acute hemodynamic response. While the underlying mechanism(s) remain to be clarified, LEVO’s effects on CVP and PCWP warrant further study of this drug as a treatment for PH-HFpEF.

Background: Serum levels of vascular cell adhesion molecule-1 (VCAM-1) are reflective of endothelial activation, a pathologic process that is associated with subclinical cardiac dysfunction. While VCAM-1 has been implicated in the pathogenesis of heart failure (HF) with preserved ejection fraction (HFpEF), the prospective association of VCAM-1 with clinically overt HF is unclear. Methods: In the Multi-Ethnic Study of Atherosclerosis, we evaluated the association of VCAM-1 at Exam 2 (2002-2004) with incident HF across ejection fraction (EF) categories (HFpEF and HF with reduced EF [HFrEF]) after adjustment for cardiovascular risk factors. Incident HF was adjudicated as first hospitalization for symptomatic HF, requiring specific clinical and/or imaging criteria. Results: Of 2,298 participants (mean age: 63.0 years, female: 53%), those with higher VCAM-1 were more likely white race, had higher blood pressure, and lower renal function. Over a median of 16.0 years, there were 102 HF events (HFpEF = 65; HFrEF = 37) ( Figure ). After covariate adjustment, VCAM-1 was independently associated with incident HF ( Table ). Upon evaluation of HF subtypes, VCAM-1 was associated with incident HFpEF, and risk effect estimates were consistent for incident HFrEF. The association of VCAM-1 with incident HF was consistent across the spectrum of age, sex, and BMI. Conclusion: In a multiethnic cohort, VCAM-1 was independently associated with incident HF over long-term follow up. These findings suggest a potential role for endothelial activation in driving clinical HF. Lifestyle and pharmacologic therapies that decrease endothelial activation may prevent the progression to clinical HF.

Abstract The diagnosis and management of pulmonary arterial hypertension (PAH) includes several advances, such as a broader recognition of extrapulmonary vascular organ system involvement, validated point-of-care clinical assessment tools, and focus on the early initiation of multiple pharmacotherapeutics in appropriate patients. Indeed, a principal goal in PAH today is an early diagnosis for prompt initiation of treatment to achieve a minimal symptom burden; optimize the patient’s biochemical, hemodynamic, and functional profile; and limit adverse events. To accomplish this end, clinicians must be familiar with novel risk factors and the revised hemodynamic definition for PAH. Fresh insights into the role of developmental biology (i.e., perinatal health) may also be useful for predicting incident PAH in early adulthood. Emergent or underused approaches to PAH management include a novel TGF-β ligand trap pharmacotherapy, remote pulmonary arterial pressure monitoring, next-generation imaging using inert gas–based magnetic resonance and other technologies, right atrial pacing, and pulmonary arterial denervation. These and other PAH state of the art advances are summarized here for the wider pulmonary medicine community.

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.

Background Serum levels of vascular cell adhesion molecule‐1 (VCAM‐1) are reflective of endothelial activation. Although VCAM‐1 has been implicated in the pathogenesis of heart failure with preserved ejection fraction (HFpEF), the prospective association of VCAM‐1 with development of clinically overt heart failure (HF) across ejection fraction categories is unclear. Methods and Results In MESA (the Multi‐Ethnic Study of Atherosclerosis), we evaluated the association of VCAM‐1 at examination 2 (2002–2004) with incident HF (HFpEF and HF with reduced ejection fraction) after adjustment for cardiovascular risk factors. Incident HF was independently adjudicated as first hospitalization for symptomatic HF. Among 2297 participants (mean age, 63 years; women, 53%), those with higher VCAM‐1 were more likely to be White race, had higher blood pressure, and had lower kidney function. Over a median of 14.4 years, there were 102 HF events (HFpEF=65; HF with reduced ejection fraction=37). After covariate adjustment, each doubling of VCAM‐1 was associated with incident HF (hazard ratio [HR], 1.94; 95% CI, 1.17–3.23; P =0.01). This association appeared stronger among current/former smokers compared with never smokers. On evaluation of HF subtypes, VCAM‐1 was associated with incident HFpEF (HR, 1.97; 95% CI, 1.04–3.72; P =0.04) but not with incident HF with reduced ejection fraction, although risk estimates were consistent (HR, 1.82; 95% CI, 0.79–4.21; P =0.16). Conclusions In a multiethnic cohort, VCAM‐1 was significantly associated with incident HF over long‐term follow‐up. These findings suggest a potential role for endothelial activation in driving clinical HF, and specifically HFpEF. Therapies that decrease endothelial activation may prevent the progression from cardiovascular risk factors to clinical HF.

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.