Postoperative Ventricular Arrhythmias after Cardiac Surgery:

Abstract

AF is frequent after cardiac surgery. However, ventricular arrhythmias are less known. The purpose of the study was to evaluate the causes and the prognostic significance of severe ventricular arrhythmias occurring after cardiac surgery. For 10 years, among 2,100 cardiac surgeries, 16 (0.8%) patients (13 men, 3 women; age 49-71 years, mean 62 +/- 9 years) without previous ventricular arrhythmias, with preserved left ventricular ejection fraction, and without acute cause of ventricular arrhythmias, developed VF (n = 4) or a sustained VT between 3 days and 3 weeks after cardiac surgery (coronary artery bypass grafting [n = 6], valve replacement [n = 10]). Rapid AF (n = 5) or slow AF (n = 1) were present at the time of VT/VF. Programmed ventricular stimulation occurred after up to three extrastimuli in the basal state and after infusion of 20-30 micrograms of isoproterenol. An echocardiogram, coronary angiography, Holter monitoring with heart rate variability (HRV) study were performed. Ventricular stimulation was negative in six patients (with AF); sustained and clinical VT was induced in 10 patients with a left ventricular ejection fraction > 0.40, except in one patient. Valvular prothesis and coronary bypass graftings were normal. In all patients, HRV was normal before surgery and decreased after cardiac surgery; before versus after surgery, respectively, HR 69 +/- 9 and 89 +/- 30 beats/min (P < 0.01), SDNN 117 +/- 31 and 50 +/- 11 ms (P < 0.001), low frequency (LF) 474 +/- 658 and 51 +/- 40 ms2 (P < 0.05), high frequency (HF) 115 +/- 23 and 33 +/- 32 ms2 (P < 0.05), LF:HF 4 +/- 3 and 1 +/- 0.6 (P < 0.01). Follow-up lasted from 6 months to 10 years (mean 3 +/- 2 years). In patients without induced VT, 1 patient died from asystole, 1 had an ICD but no subsequent events, and the other 4 untreated patients are free of events. Patients with induced VT were treated with amiodarone and beta-blockers except in one patient who died from extracardiac complications. Six of nine patients had no inducible VT with this treatment and are alive; 3 patients had inducible VT, 1 died suddenly before implantation of ICD, and 2 patients are alive with an ICD; recurrent VTs were noted in one patient and received an ICD. In conclusion, recent heart surgery may increase the risk of ventricular arrhythmias. The reduction of indexes reflecting sympathetic and parasympathetic tone could facilitate the occurrence of atrial arrhythmias (and then VT) in patients without ventricular arrhythmogenic substrate or the development of VT/VF in patients with a latent previous ventricular arrhythmogenic substrate. In patients without inducible VT, the prognosis is excellent and an ICD is not recommended in these patients. In those with inducible VT, there is a high incidence of responders to antiarrhythmic drugs with a favorable prognosis.

Impact of type of intervention for aortic valve replacement on heart rate variability

“…In cardiac surgery post-operative period, atrial and ventricular arrhythmias may occur and seem to be facilitated by a procedurerelated decrease of HRV, especially in patients with pre-existing arrhythmogenic substrate [29]. Weakness, dizziness and fainting associated with hypotension are also relatively frequent [30]: besides other common causes (anaemia, side effects of drugs, hypovolemia, transient arrhythmias, hypoglycaemia), autonomic neuropathy may constitute a relevant factor.…”

Sustained Ventricular Tachycardia Associated With Corrective Valve Surgery

“…2,[11][12][13] In 1 of the largest series reporting postoperative outcomes, VT of Ͼ30 seconds was identified in only 6 of 813 patients with isolated valve-correcting surgery. 11 Narasimhan and coworkers 13 studied 29 patients with sustained monomorphic VT after valve surgery and found bundle-branch reentry in one third of patients.…”

Update to Practice Standards for Electrocardiographic Monitoring in Hospital Settings: A Scientific Statement From the American Heart Association

“…208 Ventricular arrhythmias are common in the immedi ate postoperative period and are related to hypother mia, ischemia, and electrolyte abnormalities. 211 Risk de creases over time but is never eliminated. These rhythms have the potential to affect hemodynamic stability and to cause sudden death.…”