Results
Baseline characteristics
The study population comprised of 15,200 patients with ACS. Of them 11682 (77%) were males, 5383 (35%) suffered from diabetes mellitus 8894 (59%) had a history of arterial hypertension, 9757 (64%) had dyslipidemia and 6931 (46%) presented with STEMI. Patient’s baseline characteristics are presented in Table 1.
Ventricular tachyarrhythmia characteristics
Four hundred eighty-seven patients (3.2 %) had VTA during their hospitalization. Among those patients, 373/487 (77%) had early VTA and 114/487 (23%) had late VTA. The incidence of both types of VTA’s remained the same in the past 15 years as shown in Figure 1. Patients with late VTA were older (65±14 vs. 64±13, p<0.001) and had significantly higher incidence of co-morbidities and coronary risk factors such as diabetes mellitus, arterial hypertension, as well as known coronary artery disease, and chronic renal failure as shown in Table 1.
Outcome
Rate of MACE was higher in late VTA then in early and non-VTA (49% vs. 23% vs. 8%, respectively, p<0.001). As shown with logistic regression model the presence of late VTA was associated with three folds’ higher ratios for 30 days MACE (p<0.001), Figure 2. In- hospital and 1-year mortality rate were also higher in the presence of late VTA as compared with no VTA [HR 27.44 (95% CI 17.56- 42.49) and 9.78 (95% CI 6.57- 11.18), respectively, p<0.001]. Even after multivariate logistic regression for confounders the presence of early VTA and late VTA, were independently associated with increased risk of in-hospital mortality rate [OR 9.65 (95% CI 7.0-13.13) and 27.64 (95% CI 17.56-42.49), respectively, p<0.001], and early post- discharge mortality rate [OR 8.75 (95% CI 5.98-12.24) and 22.6 (95% CI 14.5-35.62), respectively, p<0.001]. Moreover, multivariable Cox proportional hazard analysis including baseline potential confounders confirmed that 5-year mortality rate was also higher in late VTA then in early and non-VTA (HR 8.27 vs. 2.65, for late and early VTA, respectively 95% CI 2.05-3.42).
Late vs. Early period
The 1 and 5-year all-cause mortality rate was lower during the late period as compared with the early period for patients with no VTA, early VTA and late VTA (8% vs 10%, 20% vs 25% and 37% vs 65%, all log-rank p <0.001, respectively for 1 year) and (20% vs 23%, 26% vs 29% and 45% vs 75%, all log-rank p <0.001, respectively for 5 years) as shown in Figure 3 and 4. Moreover, the late period was associated with lower all-cause mortality rates for in-hospital, 1 year and 5 years mortality rate (OR 0.56, 0.66 and 0.82, p<0.001, respectively).
In the early period ICD was implanted during hospitalization in 15 (0.2%) patients with no VTA, 3 (1.4%) patients with early VTA and 5 (8%) with late VTA (p<0.001). In the late period in hospital implantation of ICD was performed in 25 (0.4%), 8 (5%) and 0 patients, respectively (p<0.001).
In our study during early period chronic treatment with beta blockers was administered to 34%, 24% and 42.5% of patients with no VTA, early VTA and late VTA respectively, p= 0.018; beta blockers at discharge were prescribed to 78%, 72% and 51% of patients respectively, p<0.001
During the late period 38.5%, 35% and 42% of patients with no VTA, early VTA and late VTA, respectively, used beta blockers chronically, p=0.6 and 80.5%, 81.5%, 73% of patients, respectively, were discharged with beta blockers, p=0.4 Chronic angiotensin-converting-enzyme inhibitor (ACEI) treatment in early period was used in 26%, 31% and 22% of patients with no VTA, early VTA and late VTA p=0.8; ACEI after discharge were prescribed to 61%, 61.5% and 57%, respectively, p=0.9
During the late period chronic ACEI treatment was administered to 32%, 32%, 24% of patients with no VTA, early VTA and late VTA respectively, p=0.08; ACEI in discharge were prescribed to 67%, 66%, 47% of patients respectively, p=0.018