Postoperative ventricular arrhythmia tied to poor long-term prognosis
Despite being an uncommon complication of coronary artery bypass surgery (CABG), postoperative ventricular arrhythmia (POVA) increases the risk of in-hospital mortality and poor long-term prognosis, according to a recent poster presented at the recently concluded 23rd ASEAN Federation of Cardiology Congress (AFCC 2018), in Bangkok, Thailand.
Out of 2,388 patients who underwent open cardiac surgery, 0.92 percent (n=26; mean age 62.0±14.2 years; 69.9 percent male) developed POVA and were included in the analysis. A parallel group of 95 participants without POVA (mean age 64.2±13.6 years; 71.6 percent male) was also included as controls. [AFCC 2018, abstract P057]
A vast majority (n=19) of the POVA cases occurred between the 2nd and 7th postoperative days; this was followed distantly by those whose onset were within a day from the operation (n=3). In terms of POVA type, polymorphic ventricular tachycardia (VT) was the most common (46 percent), followed by monomorphic VT (39 percent).
Patients who developed POVA suffered from poorer postoperative prognosis, such as higher mortality rates in the hospital (26.9 percent vs 6.3 percent; p=0.006) and at 1-year follow-up (7.7 percent vs 4.2 percent; p=0.051).
The same was true for the occurrence of death and implantable cardioverter-defibrillator (ICD) shock (POVA vs non-POVA: 19.2 percent vs 4.2 percent; p=0.02).
Unadjusted analysis revealed that left ventricular (LV) systolic dysfunction, mitral valve surgery, right ventricular dysfunction, use of inotropic drugs, prolonged aortic cross-clamp time and emergency surgery, among others, were potential risk factors for POVA occurrence.
However, after multivariate adjustments, only LV systolic dysfunction (odds ratio [OR], 11.3; 95 percent CI, 2.7–48.2; p=0.001), cross-clamp time >75 minutes (OR, 8.7; 1.9–40.4; p=0.005) and the use of inotropic drugs (OR, 8.4; 2.2–32.4; p=0.004) remained statistically significant.
Ten POVA patients (38.5 percent) received automated ICDs prior to hospital discharge for secondary prevention. Of these, four experienced episodes of VT/ventricular fibrillation during the 1-year follow-up period. There were no reports of inappropriate shock of device complications.
“Ventricular arrhythmia after cardiac surgery is a life-threatening condition,” said researchers, noting that the observed incidence rate of 0.9 percent was lower than what was previously reported in other studies, which ranged typically from 1.6–5.0 percent.
Regardless, “[u]nlike previous reports … our study shows that [the] incidence of ventricular arrhythmias after hospital discharge as well as mortality up to 1 year is still high when compared to patients who did not have perioperative ventricular arrhythmia,” they continued.
Moreover, patterns of use of preoperative medications, such as digoxin, amiodarone and beta-blockers, were not significantly different between the POVA and non-POVA groups, suggesting that such treatments may not be effective in the general population, researchers added, though the existing data, particularly in high-risk subgroups, remain inconclusive.