Background and Goal of Study:

Elderly surgical patients with comorbidities are at a major risk for perioperative cardiac
complications. 1 We investigated continuous wireless electrocardiographic Holter monitoring (cECG) in a postoperative setting to determine (1) the degree of silent cardiac ischemia (SI) and (2) the sensitivity of different lead combinations in detection of ischemia.

Materials and methods:

cECG recordings of 51 patients aged 65 years or older having undergone peripheral arterial surgery were analysed. cECG monitoring was started after surgery and continued for 72 hours, or until discharge. The impact of posture changes on ischemia detection was evaluated with a 3-axis accelerometer. A standard 12-lead ECG, a measurement of high-sensitive troponin T (TnT), and an enquiry of ischemic symptoms were obtained preoperatively, and on the 1st, 2nd and 3rd postoperative day. The primary outcomes were perioperative myocardial infarction (PMI) and postoperative ischemia load (IL)/patient. We expressed the IL as an integral of ischemic ST- segment deviation and time. χ2- test was used to compare the differences in detected ischemic events between the lead combinations.

Results and discussion:

During 3262.7 patient-hours of monitoring, 17 patients (33.3%) had 608 transient ischemic events, all denoted by ST-segment depression (Table 1). Of 17 with ischemia, 5 patients suffered PMI.


[Table 1. Postoperative ischemia characteristics.]

Ischemia was detected best with the axial leads and V4+V5 (97.2 %) (I), followed by the axial leads and V4 (92.0 %) (II), or V5 (63.3 %) (III) (p< 0.001 for I vs. II, p< 0.001 for 1 vs. III and p< 0.001 for II vs. III). Ischemic changes occurred most frequently during hours 24 to 60 of monitoring. Ischemia was asymptomatic in 82 % of the cases.

Conclusion:

Postoperative silent cardiac ischemia is common in high-risk surgery patients, and may develop into PMI. A possibility for immediate ischemia diagnosis and treatment would further enhance the value of the surveillance.

References:

1 Devereaux PJ, Sessler DI. Cardiac Complications in Patients Undergoing Major Noncardiac Surgery. N Engl J Med 2015; 373: 2258-69.

Ischemia detected by continuous postoperative 12-lead electrocardiographic monitoring in high-risk vascular surgery patients