Unidentified Candidates for Cardiac Resynchronization Therapy: Guideline Adherence in a Large Academic Outpatient Clinic in the Netherlands

BACKGROUND: Cardiac resynchronization therapy (CRT) reduces mortality and morbidity in patients with heart failure, diminished left ventricular function, and prolonged QRS duration. We investigated adherence to the CRT guidelines and screened for unidentified CRT candidates. METHODS: Every unique patient visiting the outpatient clinic during three months was analyzed. In patients with QRS duration ≥120 ms or a paced QRS duration ≥200 ms on the electrocardiogram (ECG), left ventricular ejection fraction (LVEF), and New York Heart Association functional class were retrieved from hospital records and compared with the institutional implantable cardioverter defibrillator/pacemaker implantation database. The appropriateness of CRT indication was studied in patients who previously received CRT. RESULTS: QRS duration was <120 ms in 2,609 out of 3,053 patients screened. LVEF was ≤35% in 28 out of 282 patients with a QRS duration ≥120 ms or a paced QRS duration ≥200 ms. Of those, 11 patients were potential CRT candidates. During follow-up, three patients received a CRT device, two patients died, one patient improved, and one refused implantation, leaving four potential CRT candidates. Forty-six patients previously implanted with a CRT device visited the outpatient clinic, of whom 42 (91.3%) fulfilled the guideline criteria. Hence, 45 out of 49 patients (91.8%) qualifying for CRT had received CRT or were implanted during follow-up, and four (8.2%) CRT candidates were unidentified. CONCLUSION: In a large, tertiary academic hospital, >91% of patients fulfilling guideline criteria received CRT, and 8.2% of patients were unidentified. Systematic ECG screening of every patient may prove a simple tool to detect CRT candidates who were otherwise unrecognized.