Table 2. Studies addressing recovery of conduction after cardiac surgery.
| Study (Author, year) | Zakhia, 1992 | Kim, 2001 | Simms, 2013 | Rene, 2013 |
|---|---|---|---|---|
| Study characteristics | ||||
| Sample size | 29 | 9 | 14 | 104 |
| N completed | 25 | 7 | 13 | 98 |
| Follow-up duration (mean months) | 35 | 12 | 6 | 43 |
| Mortality n | 17% (5) | - | 7% (1) | - |
| Patient characteristics | ||||
| Age (mean) | 65 | 54 | 68 | 67 |
| Sex (%male) | 55% (16) | 33% (3) | 57% (8) | 66% (65) |
| Comorbid conditions | ||||
| CAD | - | - | 36% (5) | - |
| LVEF <50% | - | 22% (2) | 50% (7) | - |
| DM | - | 11% (1) | 29% (4) | - |
| Preoperative conduction | ||||
| LBBB | 31% (9) | - | - | 11% (11) |
| RBBB | 7% (2) | - | - | 7% (7) |
| 1st degree AV block | 7% (2) | - | - | - |
| LAFB | 3.5% (1) | - | - | 9% (9) |
| 2+ degree AV block | 0 | - | - | 0 |
| Normal sinus rhythm | - | - | - | 82% (80) |
| Atrial Fibrillation | - | - | 0 | - |
| Procedure type | ||||
| AVR | 79% (23) | 44% (4) | 100% (13) | 72% (71) |
| MVR | 10% (3) | 22% (2) | 0 | 11% (11) |
| Combined AVR/MVR | 10% (3) | 0 | 0 | 10% (10) |
| CABG | 0 | 0 | 0 | 33% (32) |
| Combined valve+ CABG | 7% (2) | 33% (3) | 0 | - |
| Pacemaker placement | ||||
| Indications | ||||
| Complete heart block n | 90% (26) | 100% (9) | 100% (13) | 100% (98) |
| Slow atrial fibrillation | 0 | 0 | 0 | 0 |
| Sinus node dysfunction | 0 | 0 | 0 | 0 |
| Mobitz II 2nd degree block | 10% (3) | 0 | 0 | 0 |
| Timing of PM implantation (median days post-operatively) | 10 | 8 | 6.6 | 6 |
| Late recovery of conduction | 16% (4) | 29% (2) | 38% (5) | 42% (41) |
Reported values represent percentage of patients in each category, with numbers in parentheses, unless specified. All studies were retrospective. Abbreviations: AVR–aortic valve replacement, MVR–mitral valve replacement, CABG–coronary artery bypass grafting CAD–coronary artery disease, LVEF–left ventricular ejection fraction, DM–diabetes Mellitus, LBBB—left bundle branch block, RBBB–right bundle branch block, PM–pacemaker