SHort Of Pace - Heart Failure (SHOP-HF)

Inclusion criteria

• Stable symptomatic heart failure (NYHA functional class ≥II) during the last month.
• Diagnosis criteria of HFpEF according to ESC guidelines:

• symptoms and signs of HF.
• left ventricular ejection fraction ≥50% by Simpson method.
• proBNP >125 pg/mL in the last month.
• at least one additional criterion: 1. relevant structural heart disease (left ventricular hypertrophy and/or left atrial enlargement); and/or 2. Diastolic dysfunction.
• Left ventricular hypertrophy was defined as wall thickness > 10 mm.
• Small ventricular volume was defined as indexed left ventricular end diastolic volume < 45 ml/m2.
• Adults ≥18 years old.
• Previous admission for acute heart failure.
• Chronotropic incompetence assessed by CPET, defined as: [(HRmax - HRrest)]/[(220 - age) - (HRrest)] < 0.62.
• Resting heart rate < 65 bpm in sinus rhythm or 70 bmp in atrial fibrillation.

Exclusion criteria

• Inability to perform a valid baseline exercise test.
• Significant primary pulmonary disease; including pulmonary arterial hypertension, chronic thromboembolic pulmonary disease or chronic obstructive pulmonary disease.
• Patient with prior history of left ventricular ejection fraction <50%.
• History of an acute coronary syndrome in the previous 12 months.
• Effort angina or signs of ischemia during CPET.
• RER threshold at <1.05 at the CPET.
• Significant primary moderate to severe valvular disease.
• Any other comorbidity with a life expectancy lower than 1 year.
• Heart rate at rest > 75 lpm.
• Other pacemaker indication.
• Pregnant women.
• Baseline rhythm different from sinus rhythm or atrial fibrillation.
• Active treatment with beta-blockers, digitalis or non dihidropiridine calcium channel blockers.