Ventricular high-rate episodes predict increased mortality in heart failure patients treated with cardiac resynchronization therapy

Figures & data

Figure 1. Flowchart for inclusion of patients. CRT-P, Cardiac Resynchronization Therapy-pacemaker; CRT-D, Cardiac Resynchronization Therapy-defibrillator; RVOT, Right Ventricular Outflow Tract.

Table I. Baseline characteristics comparing patients with and without VHR episodes during first year of follow-up.

Parameter	All (f = 220)	VHR Yes (f = 30)	VHR No (f = 190)	p value
Male (%)	178 (80.9%)	26 (86.7%)	152 (80.0%)	0.39
Age (years, median, 25th & 75th percentile)	72 (64.1 & 77.3)	75.9 (71.5 & 79.4)	71.9 (62.9 & 76.8)	0.01
Ischemic cardiomyopathy (%)	131 (59.5%)	17 (56.7%)	114 (60.0%)	0.73
NYHA Class (%)
Class I	0 (0%)	0 (0%)	0 (0%)	0.82
Class II	13 (6.6%)	11 (6.5%)	2 (7.1%)
Class III	167 (84.8%)	23 (82.1%)	144 (85.2%)
Class IV	17 (8.6%)	3 (10.7%)	14 (8.3%)
QRS Duration ms (25th & 75th)	168.0 (155 & 184)	162.5 (145.5 & 174)	168.0 (156.0 & 186.0)	0.06
Previous myocardial infarction (%)	125 (58.1%)	17 (56.7%)	108 (58.4%)	0.86
Previous CABG (%)	79 (36.2%)	9 (31.0%)	70 (37.0%)	0.53
Hypertension (%)	83 (37.7%)	15 (50.0%)	68 (35.8%)	0.14
Diabetes (%)	72 (32.7%)	10 (33.3%)	62 (32.6%)	0.94
History of AF (%)	105 (48.8%)	18 (60.0%)	87 (47.0%)	0.19
LVEF (25th & 75th)	22.0 (20.0 & 25.0)	21.0 (19.25 & 25.5)	22.0 (20.0 & 25.0)	0.79
β-Blocker use (%)	171 (79.5%)	22 (75.9%)	149 (80.1%)	0.60
ACE-inhibitor or ARB use (%)	201 (93.9%)	26 (89.7%)	175 (94.6%)	0.30
Loop diuretic use (%)	203 (94.9%)	29 (100%)	174 (94.1%)	0.18
Class I or III antiarrhythmic use (%)	13 (6.1%)	1 (3.4%)	12 (6.5%)	0.52
Digoxin use (%)	85 (39.5%)	13 (44.8%)	72 (38.7%)	0.53
Anticoagulant use (%)	113 (52.3%)	19 (63.3%)	94 (50.5%)	0.19
LBBB (%)	145 (65.9%)	23 (76.7%)	122 (64.2%)	0.42
RBBB (%)	3 (1.4%)	0 (0%)	3 (1.6%)
Atypical (%)	27 (12.3%)	4 (13.3%)	23 (12.1%)
Paced (%)	44 (20.0%)	3 (10.0%)	41 (21.6%)
Median follow-up duration months (25th & 75th)	45.8 (21.9 & 85.3)	24.8 (8.7 & 52.2)	54.3 (25.2 & 86.3)	0.003
Ventricular pacing, in % (25th & 75th)	98.0 (94.1 & 99.4)	97.3 (93.5 & 98.9)	98.0 (93.8 & 99.4)	0.16
Creatinine (25th & 75th)	115 (89 & 147)	118.5 (97.0 & 143.3)	112.0 (89.0 & 149.0)	0.92
Hemoglobin (g/L) (SD)	134 (17.7)	145.0 (18.2)	133.2 (17.4)	0.14

NYHA, New York Heart Association; CABG, Coronary Artery Bypass Grafting; LVEF, Left Ventricular Ejection Fraction; ACE, Angiotensin Converting Enzyme; ARB, Angiotensin Receptor Blocker; LBBB, Left Bundle Branch Block; RBBB, Right Bundle Branch Block; LV, Left Ventricular; AP, Anterior Posterior.

Table II. Mode of death.

n = 132	Total	VHR	No VHR	p value
Cardiac death	97 (75.8%)	19 (76.0%)	78 (78.8%)	0.763
HF	58 (46.8%)	15 (60.0%)	43 (43.4%)	0.138
AMI	16 (12.9%)	2 (8.0%)	14 (14.1%)	0.413
CA	20 (16.1%)	1 (4.0%)	19 (19.2%)	0.065
Transplant	3 (2.4%)	1 (4.0%)	2 (2.0%)	0.565
Non cardiac death	27 (21.8%)	6 (24.0%)	21 (21.2%)	0.763
Unknown cause of death^||	8 (6.1%)	0 (0.0%)	8 (7.5%)	n/a

^||These patients were excluded from statistical analyses. VHR, Ventricular high rate episode; HF, Heart failure; AMI, Acute myocardial infarction; CA, Cardiac arrest.

Figure 2. Kaplan-Meier plot of long-term survival stratified for occurrence of ventricular high rate (VHR) episodes within the first 12 months post-implant.

Table IIIa. Univariate logistic regression analysis of 5-year mortality.

Parameter	n = 220	p value	Hazard Ratio	CI
Male	220	0.198	1.561	0.792–3.077
Age, mean years	220	< 0.001	1.060	1.029–1.092
Ischemic etiology compared to dilated	201	< 0.001	2.926	1.604–5.338
NYHA Class I-II compared to III-IV^§§	190	0.414	0.610	0.187–1.995
QRS Duration, ms	217	0.324	0.995	0.986–1.005
Myocardial infarction^§§	215	0.001	2.642	1.512–4.617
Previous CABG^§§	218	< 0.001	3.957	2.176–7.196
Hypertension	220	0.405	1.262	0.730–2.181
Diabetes	220	0.627	1.150	0.654–2.023
LVEF	213	0.006	0.943	0.903–0.984
β-Blocker use	215	0.715	0.884	0.454–1.718
ACEi or ARB use	214	0.646	1.302	0.423–4.010
Loop diuretic use	214	0.035	5.323	1.122–25.250
Class I or III antiarrhythmic use	214	0.646	0.768	0.249–2.366
Digoxin use	215	0.299	1.338	0.772–2.318
Anticoagulant use^||||	216	0.016	1.948	1.133–3.348
ECG other than LBBB^#	220	0.010	2.128	1.199–3.777
Creatinine	133	< 0.001	1.021	1.011–1.032
Hemoglobin (g/L)	119	0.026	0.975	0.954–0.997
AF preoperatively	215	0.002	2.355	1.361–4.073
Previous pacemaker or ICD	218	0.094	1.791	0.905–3.543
First VHR within 1 year post implant	220	0.005	3.575	1.464–8.728

^§§Variable not included in multivariate analysis because of correlation with ischemic etiology. ^||||Variable not included in multivariate analysis because of correlation with AF preoperatively. NYHA, New York Heart Association; CABG, Coronary Artery Bypass Grafting; LVEF, Left Ventricular Ejection Fraction; ACE, Angiotensin Converting Enzyme; ARB, Angiotensin Receptor Blocker; LBBB, Left Bundle Branch Block; AF, Atrial Fibrillation; ICD, Implantable Cardioverter Defibrillator; VHR, Ventricular High Rate.

Table IIIb. Multivariate logistic regression analysis for 5-year mortality.

Parameter	p value	Odds Ratio	CI
Age, mean years	0.695	1.012	0.952–1.077
Ischemic cardiomyopathy	0.314	1.947	0.532–7.118
LVEF	0.040	0.925	0.858–0.996
Loop diuretic use	0.238	5.528	0.323–94.589
ECG other than LBBB	0.901	1.100	0.244–4.948
Creatinine	0.037	1.016	1.001–1.031
Hemoglobin (g/L)	0.061	0.971	0.942–1.001
Preoperative AF	0.051	3.044	0.997–9.294
Previous pacemaker or ICD	0.319	2.650	0.389–18.032
First VHR within 1 year post implant	0.022	9.963	1.387–71.593

LVEF, Left Ventricular Ejection Fraction; LBBB, Left Bundle Branch Block; AF, Atrial Fibrillation; ICD, Implantable Cardioverter Defibrillator; VHR, Ventricular High Rate.