Aneurysmal subarachnoid hemorrhage (aSAH) is associated with a high burden of disease as the affected patients tend to be relatively young and the mortality rate is high [1]. Multiple clinical scales were used to assess the severity and prognosis of aSAH. Among them, the Hunt and Hess scale is the most widely used in initial grading to forecast outcomes, [2] and the modified Fisher Scale predicts the risk of cerebral vasospasm, which is a relatively common complication of aSAH [3]. In addition, after dealing with the initial aneurysmal rupture, various secondary complications such as vasospasm, pulmonary edema, or infection can occur within 3–14 days and are associated with poorer clinical outcomes [4], [5]. It is difficult to early recognize the complications, particularly when the patients are transferred from intensive care unit (ICU) into general wards where continuous monitoring essential for aSAH management is not routinely available.

Among physiological monitors, electrocardiography (ECG) is measured at either a single time point or serial rather than continuous recording and might provide limited value on preclinical detection since only 1–4 % of aSAH patients have significant arrhythmias including ventricular tachycardia and atrial tachyarrhythmia in previous studies [6], [7], [8]. Heart rate variability (HRV) was used to assess autonomic cardiac regulation through a period of rhythm record [9], [10]. It has been proofed to reflect both delayed ischemic and infectious complications for aSAH patients [11], [12]. However, with short-term monitoring, there are challenges to utilize HRV for preclinical detection of complications in patients with aSAH since they often develop a pro-inflammatory response from the bleeding event itself [13]. Even in the absence of an infection, systemic inflammatory response syndrome (SIRS) commonly develops in those patients within the first few days and influences the heart rhythm [14].

Lead-based monitoring was shown to be effective in detecting subclinical changes due to various secondary complications by identifying QTc prolongation, and changes in ECG and HRV values [9], [15]. However, lead-based monitors are usually bulky, and previous studies have reported low compliance with many lead-based extended ECG monitoring devices, including Holter monitors, event monitors, and mobile cardiac outpatient telemetry, and that the use of these monitors may interfere with other clinical practice [16]. Recently, single-lead, less-obtrusive, adhesive-patch monitoring platforms have been developed to replace conventional Holter monitoring for prolonged monitoring to detect arrhythmic events in patients referred for ambulatory ECG monitoring [17].

In this study, we sought to verify the feasibility of a novel single-use ECG patch on aSAH patients in the ward where continuous ECG monitoring is unavailable. Longer recording to heart rhythm consequently acquires more data to detect significant arrhythmia and to calculate HRV parameters. We hypothesized the device is feasible in the general ward. Meanwhile, the arrhythmias and HRV parameters may be correlated with prognosis including the occurrence of secondary complications.