Difficulty recruiting

This trial will compare two management strategies for HF patients with preserved LV function in sinus rhythm and LBBB. The control group will be treated with practice guideline optimal medical therapy for HF. The experimental group will be treated with CRT in addition to optimal medical therapy for HF. In addition, the trial will further compare two methods of delivering CRT. One experimental group will receive BiV-CRT, while the second experimental group will receive CS-CRT.

Inclusion Criteria:

• Patients with NYHA class II-IVa HF symptoms and are on diuretic therapy
• LVEF > 35% (stratify by LVEF 36-49% and LVEF ≥ 50%), and recovered LVEF (previously LVEF ≤ 35%, but improved to LVEF > 35% with medical therapy)
• Patients with LVEF ≥ 50% must also have either left atrial enlargement (any of the following: LA diameter ≥3.8 cm, LA length ≥5.0 cm, LA volume ≥55 ml, LA volume index (LAVi) ≥29 mL/m2) or LV hypertrophy (LV mass index (LVMI) ≥115 g/m2 for males and ≥ 95g/m2 for females)
• LBBB and QRS duration ≥ 140 msec. for men or ≥ 130 msec. for women, and with mid-QRS notching or slurring in ≥ 2 leads
• Patients may have permanent RV pacing with a QRS duration ≥180ms
• Patients may have permanent atrial fibrillation with good rate control defined as a resting heart rate of ≤80 bpm at rest and ≤110 bpm with 6-minute walk test
• NT-proBNP ≥ 600 pg/ml on stable medical therapy without previous heart failure hospitalization in the last 12 months, or ≥400 pg/ml on stable medical therapy if there was a heart failure hospitalization within the previous 12 months
• Appropriate pharmacological treatment of HF and co-morbidities.
• Stable diuretic and other HF medications for at least four weeks

Exclusion Criteria:

• Serum creatinine >180 μmol/L; or estimated glomerular filtration rate [eGFR] ≤30 mL/min/1.73 m2, calculated using the Modification of Diet in Renal Disease formula
• In-hospital patients with acute cardiac or non-cardiac illness that requires intensive care
• Acute coronary syndrome (including MI) <4 weeks
• Coronary revascularization (CABG or PCI) < 3 months
• Uncorrected or uncorrectable primary valvular disease
• TAVI < 3 months
• Restrictive, or reversible form of cardiomyopathy, cardiac amyloidosis
• Severe primary pulmonary disease such as cor pulmonale, primary pulmonary hypertension (may include secondary pulmonary hypertension, if mean pulmonary pressure is ≤ 70 mm Hg)
• Expected to undergo cardiac transplantation within one year (status I)
• Patients with a life expectancy of less than one year from non-cardiac cause.
• Patients included in other clinical trials that will affect the objectives of this study
• Patients who are pregnant/intend to get pregnant
• Those unable or unwilling to provide informed consent