Table 1.
Patient characteristics at the time of cardiac resynchronization therapy
| CRT respondera
(n = 40) |
CRT non-responder (n = 65) |
p-value | |
|---|---|---|---|
| Age, years, mean (± SD) | 52 ± 11 | 51 ± 9 | 0.546 |
| Male sex, n (%) | 21 (53) | 42 (65) | 0.258 |
| Race, n (%) | 0.538 | ||
| White | 37 (93) | 60 (92) | |
| Black | 1 (3) | 4 (6) | |
| Hispanic | 1 (3) | 0 | |
| Asian | 1 (3) | 1 (2) | |
| Missense mutation, n (%) | 17/39 (44) | 27/64 (62) | 0.838 |
| NYHA class, n (%) | n = 34 | n = 47 | 0.482 |
| I | 4 (12) | 6 (13) | |
| II | 15 (44) | 25 (53) | |
| III/IV | 15 (44) | 16 (34) | |
| LVEF %, mean (± SD) | 29 ± 8 | 36 ± 11 | 0.001 |
| LVEF <35%, n (%) | 33/40 (83) | 34/65 (52) | 0.002 |
| LVEDD mm, mean (±SD) | 59 ± 8 | 59 ± 7 | 0.981 |
| Atrio-ventricular block, n (%) | n = 39 | n = 61 | 0.619 |
| None/first degree | 9 (23) | 18 (29) | |
| Mobitz I | 6 (15) | 7 (11) | |
| Mobitz II | 5 (13) | 4 (6) | |
| Complete heart block | 19 (49) | 32 (63) | |
| Atrial fibrillation/flutter, n (%) | 28/39 (72) | 50/65 (77) | 0.559 |
| Primary prevention ICD, n (%) | 24/36 (67) | 36/51 (71) | 0.697 |
| Initial device before upgrade, n (%) | 0.091 | ||
| Single ICD | 3 (8) | 7 (11) | |
| Dual ICD | 8 (20) | 23 (35) | |
| Dual PPM | 15 (38) | 13 (20) | |
| Single PPM (ventricular) | 0 | 1 (2) | |
| None (primary CRT implant) | 14 (35) | 21 (32) | |
| Ventricular pacing pre-CRTb, %, mean (±SD) | 93 ± 13 | 72 ± 38 | 0.015 |
| Medications, n (%) | |||
| ACEi/ARB/ARNI | 29/37 (78) | 38/56 (68) | 0.292 |
| Beta blocker | 28/37 (76) | 39/57 (68) | 0.480 |
| Mineralocorticoid receptor antagonist | 9/35 (26) | 21/56 (38) | 0.204 |
| Furosemide (or equivalent) | 22/35 (63) | 29/54 (54) | 0.344 |
| Furosemide (or equivalent), mg, median (range) | 20 (0–40) | 15 (0–40) | 0.414 |
| NT-proBNP, pg/ml, median (range) | n = 12 1069 (51.5–2297) | n = 23 540 (150–878) | 0.775 |
| QRS duration, mean (±SD), ms | 168 ± 31 | 166 ± 33 | 0.821 |
| QRS duration >150 ms, n (%) | 25/33 (76) | 35/45 (77) | 0.834 |
| QRS morphology, n (%) | n = 35 | n = 57 | 0.226 |
| LBBB | 13 (37) | 15 (26) | |
| IVCD | 1 (3) | 8 (14) | |
| RBBB | 0 | 1 (2) | |
| Paced | 21 (60) | 33 (58) |
ACEi, angiotensin-converting enzyme inhibitor; ARB, angiotensin II receptor blocker; ARNI, angiotensin receptor–neprilysin inhibitor; CRT, cardiac resynchronization therapy; ICD, implantable cardioverter defibrillator; IVCD, intraventricular conduction delay; LBBB, left bundle branch block; LVEDD, left ventricular end-diastolic dimension; LVEF, left ventricular ejection fraction; NT-proBNP, N-terminal pro B-type natriuretic peptide; NYHA, New York Heart Association; PPM, permanent pacemaker; RBBB, right bundle branch block; SD, standard deviation.
CRT responders experienced an improvement in LVEF ≥5%, ~6 months after resynchronization.
Restricted to patients with an existing pacemaker and/or defibrillator prior to CRT implantation.