Prognostic impact of recurrences in patients with electrical storm

Figures & data

Table 1. Baseline characteristics.

Characteristic	Non-ES-recurrence (n = 65; 75%)	ES- recurrence (n = 22; 25%)	p Value
Age, median (range)	66 (22–85)	75 (55–82)	.098
Male gender, n (%)	54 (83)	20 (91)	.373
Cardiovascular risk factors, n (%)
Arterial hypertension	42 (65)	13 (59)	.642
Diabetes mellitus	16 (25)	6 (27)	.804
Hyperlipidemia	26 (40)	11 (50)	.412
Smoking	13 (20)	2 (9)	.242
Cardiac family history	6 (9)	1 (5)	.485
Comorbidities, n (%)
Coronary artery disease	45 (69)	13 (59)	.383
Acute myocardial infarction	0 (0)	0 (0)	-
Cardiogenic shock	2 (3)	0 (0)	1.000
CPR	5 (8)	0 (0)	.324
Atrial fibrillation	26 (40)	10 (46)	.653
Cardiomyopathy	13 (20)	10 (46)	.019
Dilated cardiomyopathy	9 (14)	10 (46)	.019
Hypertrophic cardiomyopathy	3 (5)	0 (0)	.568
ARVD	1 (2)	0 (0)	1.000
Non-compaction cardiomyopathy	0 (0)	0 (0)	-
Long QT syndrome	0 (0)	1 (5)	.253
Brugada syndrome	2 (3)	0 (0)	1.000
Intoxication	1 (2)	0 (0)	1.000
Electrolyte disorders	9 (14)	4 (18)	.622
Infectious cause	1 (2)	4 (18)	.014
Electrophysiological examination, n (%)	19 (29)	3 (14)	.146
VT ablation	15 (7)	3 (100)	.861
Laboratory data, (mean ± SD)
Hemoglobin [mmol/L]	5.2 ± 0.8	4.6 ± 0.6	.001
Potassium [mmol/L]	4.0 ± 0.7	4.3 ± 0.6	.082
Creatinine [µmol/L]	123.8 ± 44.2	141.4 ± 86.6	.285
C-reactive protein [mg/L]	315 ± 78	250 ± 70	.638
Troponin I [ng/L]	0.4 ± 0.1	0.2 ± 0.1	.160
Medication at discharge, n (%)
Beta-blocker	60 (95)	20 (95)	1.000
ACE-inhibitor/ ARB	50 (79)	17 (81)	.875
Statin	39 (62)	11 (52)	.441
Amiodarone	30 (48)	15 (71)	.058
ECG data, ms (mean ± SD)
PQ	214 ± 41	255 ± 7	.208
QRS	127 ± 38	134 ± 27	.934
QT	430 ± 42	466 ± 55	.272
LVEF, n (%)
≥ 55%	8 (14)	1 (5)	.081
54–45	6 (10)	1 (5)
44–35%	9 (15)	0 (0)
≤35%	36 (61)	19 (91)
Type of ICD, n (%)
ICD	57 (88)	19 (86)	.948
CRT-D	6 (9)	2 (9)
s-ICD	2 (3)	1 (5)
ICD indication, n (%)
Primary prevention	26 (41)	6 (27)	.264
Secondary prevention	38 (59)	16 (73)
ICD programming, bpm, median (IQR)
VT detection threshold	171 (164–172)	169 (157–174)	.274
VF detection threshold	214 (215–222)	214 (213–224)	.392

ACE: angiotensin-converting enzyme; ARB: angiotensin receptor blocker; ARVD: arrhythmogenic right ventricular dysplasia; CPR: cardiopulmonary resuscitation; CRT-D: cardiac resynchronisation therapy defibrillator; ECG: electrocardiogram; ES: electrical storming; ICD: implantable cardioverter-defibrillator; IQR: inter quartile range; LVEF: left ventricular ejection fraction; SEM: standard error of measurement; VF: ventricular fibrillation; VT: ventricular tachycardia.

Statistically significant p-values are displayed as bold.

Figure 1. Prognostic impact of ES-R on all-cause mortality (left panel), overall rehospitalization (middle panel) and MACE (right panel) at long-term follow-up.

Table 2. Primary and secondary endpoints.

Characteristic	Non-ES-recurrence (n = 65; 75%)	ES- recurrence (n = 22; 25%)	p Value
Primary endpoint, n (%)
All-cause mortality	21 (32)	11 (50)	.137
Secondary endpoints, n (%)
In-hospital mortality	2 (3)	0 (0)	1.000
First rehospitalization, overall	23 (37)	14 (64)	.031
ES-R	0 (0)	5 (23)	1.000
VT	13 (20)	6 (27)	.544
VF	0 (0)	0 (0)	-
CPR	1 (2)	1 (5)	1.000
Acute heart failure	8 (12)	7 (32)	.001
Acute myocardial infarction	1 (2)	0 (0)	1.000
Stroke	1 (2)	0 (0)	1.000
MACE	23 (35)	12 (55)	.113

CPR: cardiopulmonary resuscitation; ES: electrical storming; MACE: major adverse cardiac event; VF: ventricular fibrillation; VT: ventricular tachycardia.

Statistically significant p-values are displayed as bold.

Table 3. Multivariable Cox regression model to evaluate prognostic factors influencing ES-R with LVEF as discrete variable.

Variable	HR	95% CI	p Value
Age	0.997	0.949–1.047	.895
Male gender	2.604	0.325–20.878	.368
Diabetes mellitus	0.970	0.291–3.235	.961
Impaired renal function	0.526	0.176–1.569	.249
Coronary artery disease	0.542	0.192–1.534	.249
LVEF <35%	12.417	1.329–115.997	.027
VT ablation	0.806	0.222–2.922	.742

CI: confidence interval; ES-R: reoccurrence of electrical storm; HR: hazard ratio; LVEF: left ventricular ejection fraction; VT: ventricular tachycardia.

Impaired renal function defines as creatinine >106 µmol/L.

Statistically significant p-values are displayed as bold.

Table 4. Multivariable Cox regression model to evaluate prognostic factors influencing ES-R with LVEF as continuous variable.

Variable	HR	95% CI	p Value
Age	0.997	0.949–1.045	.890
Male gender	2.605	0.326–20.813	.367
Diabetes mellitus	0.969	0.290–3.237	.960
Impaired renal function	0.554	0.185–1.655	.290
Coronary artery disease	0.551	0.196–1.553	.260
LVEF <35%	3.390	1.022–11.237	.046
VT ablation	0.810	0.223–2.954	.740

CI: confidence interval; ES-R: reoccurrence of electrical storm; HR: hazard ratio; LVEF: left ventricular ejection fraction; VT: ventricular tachycardia.

Impaired renal function defines as creatinine >106 µmol/L.

Statistically significant p-values are displayed as bold.