Patients who consecutively underwent de novo CRT implantation, CRT upgrade, and DDDR ICD implantation at the Cardiology Clinic of Bursa Postgraduate Hospital between January 2019 and December 2023 according to the European Society of Cardiology (ESC) guideline criteria were included in the study.

100 patients receiving de-novo CRT, 38 patients upgrading from RV pacing to CRT, and 169 patients receiving a DDDR-ICD implantation were included the study. Inclusion criteria were left ventricular ejection fraction lower than 35% and either QRS longer than 130ms for CRT groups or QRS≤120ms for the DDDR-ICD group. Primary endpoints were all-cause mortality and hospitalization for heart failure during a follow-up period extending up to 5 years.

Inclusion Criteria:

De novo CRT group:

• Sinus rhythm,
• age higher than 18,
• EF lower than 35%,
• New York Heart Association (NYHA) class II-IV,
• QRS >130 ms,
• patients with atrial fibrillation (AF) who converted to sinus rhythm and who remained symptomatic despite 3-6 months of guideline-directed medical therapy.

CRT upgrade group:

• Sinus rhythm,

• age higher than 18,

• EF lower than 35%,

• NYHA class II-IV,

• QRS duration >130 ms with RV pacing,

  -> 20% RV pacing rate,

• patients with AF who converted to sinus rhythm, at least 6 months since pacemaker implantation, and symptomatic despite 3-6 months of guideline directed medical therapy.

DDDR ICD group:

• Sinus rhythm,
• age higher than 18,
• EF lower than 35%,
• QRS ≤120 ms,
• NYHA class II-IV,
• patients with AF converted to sinus rhythm,
• receiving guideline-directed medical therapy.

Exclusion Criteria:

• patients with atrial fibrillation
• LV EF higher than 50 %
• NYHA Class 1
• Patients with active infection or cancer

Patients who consecutively underwent de novo CRT implantation, CRT upgrade, and DDDR ICD implantation at the Cardiology Clinic Heart failure group in Sinus rhythm