Myocardial Mechanisms in Heart Failure With Preserved Ejection Fraction

Inclusion Criteria:

• HFpEF criteria

1. Age ≥30 years.

2. Left ventricular ejection fraction ≥50% measured by echocardiography, CMR orMUGA (measured within one year + clinical stability)

3. Definition of HFpEF: signs and/or symptoms of HF, NYHA functional class II-IV,and at least one of the following:

4. Elevated BNP (≥75 pg/ml in sinus rhythm or ≥225 pg/ml in atrialfibrillation/flutter) or NTproBNP (≥225 pg/ml in sinus rhythm or ≥675 inatrial fibrillation/flutter) at baseline. Choice of BNP or NTproBNP isbased on availability at each clinical center.

5. Prior HF hospitalization (primary reason for the hospitalization is HFwith elevated natriuretic peptide levels [using the thresholds listedabove], requiring IV diuresis for HF, or pulmonary edema or pulmonaryvascular congestion on chest radiography).

6. Previously documented elevated pulmonary capillary wedge pressure (PCWP)at rest (≥15 mmHg) or during exercise (≥25 mmHg for supine exercise orPCWP/cardiac output ratio ≥2 mmHg/L/min for upright exercise).

7. Elevated H2FPEF score69 (≥5) or HFA-PEFF70 score (≥5).

Suspected HFpEF criteria

1. Age ≥30 years.

2. Left ventricular ejection fraction ≥50% measured by echocardiography, CMR or MUGA (measured within one year + clinical stability)

3. Signs and/or symptoms of HF, NYHA functional class II-IV and all of the following:

4. Does not meet BNP or NT-proBNP criteria for HFpEF (above)

5. No prior HF hospitalization meeting HF criteria (above)

6. No previous hemodynamic catheterization documentation of HF (as above)

Exclusion Criteria:

1. Inadequate echo or fluoroscopic images.

2. Neck anatomy unfavorable for jugular venous cannulation

3. Therapy with direct oral anticoagulants without cessation for a period (age,renal function, and agent specific) deemed adequate to normalize coagulationaccording to local clinical guidelines.

4. Previous or ongoing therapy with warfarin with INR ≥ 1.6 measured day before orof EMB

5. Platelet count < 50,000/ml

6. Active bleeding or coagulation disorder

7. Infection or fever

8. Endocarditis

9. Pregnancy

10. Intracardiac thrombus

11. RV Aneurysm

12. Clinically significant tricuspid, pulmonary or aortic valve stenosis

13. Tricuspid or pulmonary mechanical valve prosthesis

14. Left bundle branch block