Table 2. Univariable and multivariable Cox regression models demonstrated associations between incident ICD shock (N=25) and diffuse myocardial fibrosis measured by ECV in myocardium without LGE.
The multivariable models stratified for ICD indication (primary versus secondary prevention). The clinical model adjusted for variables believed to represent principal mediators of risk on clinical grounds (i.e., ECV, BNP, extent of myocardial infarction, and extent of focal myocardial fibrosis) within the constraints of limited numbers of events. The stepwise model employed automatic selection of variables associated with outcomes (based on p<0.10) stratified by ICD indication.
| Variable | Univariable HR (95% CI) |
χ 2 | p value |
Clinical Multivariable HR (95% CI) |
χ 2 | p value |
Stepwise Multivariable HR (95% CI) |
χ 2 | p value |
|---|---|---|---|---|---|---|---|---|---|
| Demographics | |||||||||
| Age (10-year increase) | 1.11 (0.82-1.50) | 0.4 | 0.516 | 1.56 (0.94-2.61) | 2.9 | 0.088 | |||
| White race | 1.33 (0.31-5.67) | 0.2 | 0.697 | ||||||
| Male | 0.80 (0.36-1.78) | 0.6 | 0.581 | ||||||
| Comorbidity | |||||||||
| ICD for secondary prevention | 1.11 (0.46-2.66) | 0.1 | 0.815 | ||||||
| Diabetes | 0.71 (0.28-1.78) | 0.5 | 0.462 | ||||||
| Hypertension | 1.07 (0.47-2.42) | 0.0 | 0.879 | ||||||
| Smoking (active) | 2.46 (1.09-5.57) | 4.6 | 0.031 | 3.06 (0.97-9.66) | 3.6 | 0.057 | |||
| Coronary artery bypass surgery | 0.25 (0.03-1.83) | 1.9 | 0.171 | ||||||
| Atrial fibrillation or flutter | 1.87 (0.84-4.17) | 2.4 | 0.124 | 4.24 (0.91-19.8) | 3.4 | 0.066 | |||
| Ischemic cardiomyopathy | 1.00 (0.45-2.21) | 0.0 | 0.998 | ||||||
| Laboratory Data | |||||||||
| Glomerular filtration rate, per 10 mL/min/1.73m2 decrease) | 1.04 (0.89-1.23) | 0.2 | 0.673 | ||||||
| Hematocrit (per 5% decrease) | 1.70 (1.22-2.37) | 9.9 | 0.002 | ||||||
| Log BNP, pg/mL | 2.29 (1.41-3.71) | 11.3 | <0.001 | 1.66 (0.95-2.89) | 3.2 | 0.073 | |||
| CMR Data | |||||||||
| ECV (excluding any LGE), (per 5% increase) | 2.47 (1.54-3.95) | 14.1 | <0.001 | 2.17 (1.17-4.00) | 6.1 | 0.014 | 3.94 (1.77-8.78) | 11.2 | <0.001 |
| Native T1 (per 50 msec increase) | 1.35 (1.02-1.79) | 4.3 | 0.037 | ||||||
| EF (per 5% decrease) | 0.99 (0.87-1.14) | 0.0 | 0.915 | ||||||
| GLS (per 5% increase)* | 0.74 (0.46-1.18) | 1.6 | 0.205 | ||||||
| Myocardial infarction by LGE (present/absent) | 0.91 (0.41-2.01) | 0.1 | 0.817 | ||||||
| Myocardial infarction by LGE (per 5% increase) | 1.12 (0.98-1.27) | 2.8 | 0.092 | 1.13 (0.96-1.32) | 2.1 | 0.148 | 1.18 (0.98-1.41) | 3.1 | 0.080 |
| Non-ischemic scar by LGE (present/absent) | 0.83 (0.34-1.98) | 0.2 | 0.666 | 1.39 (0.43-4.56) | 0.3 | 0.585 | |||
| Non-ischemic scar by LGE (per 5% increase) | 0.17 (0.00-72.6) | 0.3 | 0.561 | ||||||
| Midwall fibrosis by LGE | 0.99 (0.41-2.38) | 0.0 | 0.985 | ||||||
| Moderate or severe mitral regurgitation by CMR, | 0.31 (0.04-2.32) | 1.3 | 0.256 | ||||||
| Left ventricular mass index, per 10 g/m2 | 0.92 (0.75-1.13) | 0.6 | 0.423 | ||||||
| End diastolic volume index (per 10 mL/m2) | 1.04 (0.95-1.13) | 0.6 | 0.435 | ||||||
| End systolic volume index (per 10 mL/m2) | 1.02 (0.94-1.11) | 0.3 | 0.606 |
*
There were 5 patients for whom GLS could not be measured.