Tiny study tests ablation for tough heart condition – but ends early

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * between 18 to 90 years of age, male or female * Left Ventricular Ejection Fraction (LVEF) \> 50% by echocardiogram during routine screening or within 12 months prior to enrollment day. * Symptoms of heart failure requiring treatment with diuretic therapy for at least 30 days preceding enrollment. * Symptomatic paroxysmal or persistent atrial fibrillation. * Paroxysmal atrial fibrillation defined as recurrent AF (at least 2 episodes) that terminated spontaneously within 7 days * Persistent AF was defined as AF which is sustained beyond 7 days, or lasting less than 7 days but necessitating pharmacologic or electrical cardioversion * Included within the category of persistent AF is "long-standing persistent AF" defined as continuous AF of greater than 1 year in duration * AF episodes had to be documented in the last 3 months prior to enrollment by ECG, Holter monitor, Loop recorder, memory of the implanted device, or any suitable device. * Current symptoms of heart failure (NYHA II-IV) at the enrollment visit (Visit 1) * Structural heart disease evidenced by one or both of the following echocardiographic findings (done during the transthoracic echocardiography (TTE) within 6 months of enrollment) * Left atrial enlargement (LAE) defined as LA width \> 3.8 cm or LA length \> 5.0 cm, or LA area \> 20 cm2 or LA volume \> 55 mL or LA volume index \> 29 ml/m2. (of note, LA length greater than 6.0 cm will be excluded) * Left ventricular hypertrophy (LVH) defined by septal thickness or posterior wall thickness \> 1.0 cm * And at least one of the following: * A heart failure hospitalization lasting over 12 hours and including intravenous diuretics at a healthcare facility within 12 months prior to the enrollment visit. * An elevated pro-brain natriuretic peptide (BNP) (\>100 pg/mL, or N-terminal pro b-type natriuretic peptide (NT-proBNP)\>300 pg/mL) * Hemodynamic testing consistent with HFpEF physiology including pulmonary capillary wedge pressure (PCWP) (or LVEDP) ≥ 15 mmHg. Exclusion Criteria: * Previous left heart ablation procedure for AF * Contraindication to chronic anticoagulation therapy or heparin * Longstanding atrial fibrillation, defined here as greater than 3 years of persistent atrial fibrillation * Severe left atrial dilatation, with LA length \> 6.0 cm, optimally from parasternal long view * Acute coronary syndrome within 4 weeks as defined by electrocardiographic (ECG) ST segment depression or prominent T-wave inversion and/or positive biomarkers of necrosis (e.g. troponin) in the absence of ST-segment elevation and in an appropriate clinical setting (chest discomfort or angina equivalent). * Cardiac surgery, angioplasty, or cerebrovascular accident within 4 weeks prior to enrollment. * Planned cardiovascular intervention * Listed for heart transplant * Cardiac assist device implanted or need for mechanical hemodynamic support or inpatient admission * Life expectancy less than 1 year * Uncontrolled hypertension, defined as resting systolic blood pressure \>190 and/or resting diastolic pressure\>110 * Chronic Kidney Disease (CKD) stage 4-5 (GFR\<25 ml/min/1.73m2), or on hemodialysis * Cardiac diagnosis in addition to or other than HFpEF: * Active myocarditis * Hypertrophic obstructive cardiomyopathy * Severe valvular disease * Restrictive or constrictive cardiomyopathy, including known amyloidosis, sarcoidosis, hemochromatosis * Complex congenital heart disease * Constrictive pericarditis * Severe pulmonary hypertension (RVSP \> 60 mmHg), not secondary to HFpEF * Non-cardiac pulmonary edema * Clinical evidence of digoxin toxicity * Sepsis * Inability to comply with planned study procedures * Pregnancy or nursing mothers * Uncontrolled hypothyroidism or hyperthyroidism * BMI of \>65 kg/m2