Introduction: Although the identification of silent myocardial ischemia (SMI) has prognostic significan-ce, ECG Holter monitoring in stable coronary artery disease is indicated only for the diagnosis of arrhyth-mias. There is scarce data from the literature about SMI and ventricular arrhythmias identified by ECG Holter monitoring.
Objective: The relationship between SMI and the pre-sence and severity of ventricular arrhythmias assessed by ECG Holter monitoring in stable coronary artery disease.
Methods: Patients with stable coronary heart disea-se diagnosed according to the ESC 2013 Guidelines, asymptomatic, were assessed for cardiovascular risk factors (CVRF), history of myocardial infarction and/ or myocardial revascularization, the presence of athe-rosclerosis in other vascular territories, chronic kid-ney disease (CKD), left ventricular ejection fraction (LVEF), glycosylated hemoglobin (HbA1c) and drug therapy. On 12-channel ECG Holter Monitoring for 24 hours, ventricular arrhythmias were recorded and SMI was defined by transient ST segment depression of at least 0.5 mV, with a duration of at least 60 seconds in at least 2 derivations.
Results: 62 patients, mean age 69.5±10.6 years, 56.4% men, 40.3% diabetic, 88.7% hypertensive, 20.9% with history of myocardial infarction and 33.9% with pre-vious myocardial revascularization interventions were included. 16.1% of the patients had LVEF <40%, 17.7% CKD, and 11.3% peripheral arterial disease. SMI was identified in 40.3% of the patients, with a median du-ration of 47 minutes (min 4, max 899 minutes). SMI patients had more frequent diabetes mellitus (56% vs. 29.7%, p=0.036), higher HbA1c (6.57±1.15 vs. 5.96±1.01%, p=0.04) and lower eGFR (52.3±15.7 vs. 54.5±14.8 ml/min/m², p=0.05). On ECG Holter moni-toring, patients with SMI had a higher mean heart rate (70.4±6.7 vs. 66.9±7.5 bpm, p=0.05), a higher number of ventricular premature beats (913.1±249 vs. 762.3±127, p=0.037), several episodes of ventricular bigeminism (20.4±5.7 vs. 6.5±2.4, p=0.013) and unsustained ven-tricular tachycardia (2.3% vs. 0.4%, p=0.027). There was a significant correlation between the duration of the ischemic episodes and the number of ventricular premature beats (r=0.53, p=0.06), the duration of the maximum QTc interval (r=0.63, p=0.03) and the mean heart rate (r=0.64, p=0.005). There were no significant differences between patients with and without SMI in CVRF, myocardial infarction or myocardial revascula-rization history, atherosclerotic disease in other territo-ries, LVEF and anti-ischemic therapy.
Conclusions: In patients with stable coronary artery disease, silent myocardial ischemia is significantly associated with ventricular arrhythmias and is more common in diabetic patients and those with advanced chronic renal disease. In addition to optimizing an-ti-ischemic treatment, effective glycemic control and prevention of decline in renal function may contribute to ameliorating myocardial ischaemia and controlling ventricular arrhythmias.