Bowel preparation for colonoscopy and hypokalemia: at the heart of the problem!

Using the Cardiac-Electrophysiological Balance Index to Predict Arrhythmia Risk After Colonoscopy

Background and Objectives: Colorectal cancer is the second leading cause of cancer-related deaths in the U.S., and colonoscopy is a critical tool for colon cancer screening and diagnosis. Electrolyte disturbances and autonomic nervous system dysfunction that may occur due to bowel preparation and the colonoscopy procedure itself may play a role in the development of cardiac arrhythmia. This study aimed to assess the index of cardiac-electrophysiological balance (iCEB) to predict ventricular arrhythmia risk related to colonoscopy. Materials and Methods: Patients undergoing elective colonoscopy with a normal sinus rhythm were included. Electrocardiography (ECG) recordings both before bowel preparation and after the colonoscopy procedure were obtained. Values of the index of cardiac-electrophysiological balance (iCEB) were compared. Results: Among 36 patients, it was determined that the heart rate values of the patients before bowel preparation were higher than the heart rate values after colonoscopy [74.5 (60-108) bpm vs. 68.5 (53-108) bpm, p = 0.021]. The duration of QT interval increased (370.9 ± 27.8 ms vs. 398.7 ± 29.4 ms, p < 0.001) and the iCEB increased from 4.1 ± 0.5 to 4.5 ± 0.6 (p < 0.001), indicating a significant post-procedural risk of ventricular arrhythmias. Conclusions: These findings suggest that routine iCEB assessment post-colonoscopy could identify high-risk patients requiring closer monitoring.

Comparative evaluation of enema alone and in combination with oral polyethylene glycol for bowel preparation before transvaginal pelvic floor reconstruction in elderly patients: a retrospective cohort study

The aim of this retrospective study was to assess the value of using an enema alone for mechanical bowel preparation (MBP) before transvaginal pelvic floor reconstruction (TPFR) in patients ≥65 years old. In total, 190 patients were included [81 in the enema group vs. 109 in the enema + polyethylene glycol (PEG) group]. The levels of serum potassium (p = .004) and calcium (p = .005) were higher in the enema group after surgery. The decrease in serum calcium was more significant in the enema + PEG group (p = .027). More patients in the enema + PEG group developed hypokalaemia (p = .035) or hypocalcaemia (p = .008) after surgery. The incidence of thrombus and surgical site infection was similar and earlier bowel movement was evident in the enema group (p = .000). Overall, the enema group used more laxatives (p = .026). Using enema alone before TPFR reduces the incidence of electrolyte disturbances with no increase in surgical complications in elderly patients.IMPACT STATEMENTWhat is already known on this subject? TPFR is an effective treatment for pelvic organ prolapse (POP) in elderly women. Bowel preparation performed before gynecological surgery can reduce surgical site infection, but increase discomfort and electrolyte disturbance.What do the results of this study add? The levels of serum potassium and calcium were lower in the enema + PEG group than in the enema group after surgery and more patients developed hypokalaemia or hypocalcaemia in the enema + PEG group. The incidence of thrombus and surgical site infection was similar between the two groups. Bowel movement was earlier in the enema group.What are the implications of these findings for clinical practice and/or future research? Using enema alone before TPFR reduces the incidence of electrolyte disturbance and does not increase surgical complications. This conclusion needs to be confirmed by random controlled trial studies in the future.

A Galvanizing Solution: Colonoscopy Bowel Preparation as a Trigger for Supraventricular Tachycardia

BACKGROUND

Polyethylene glycol (PEG)-based solutions are among the most commonly used bowel preparation regimens for colonoscopy. Although these solutions are well tolerated, rare adverse cardiac events have been reported.

OBJECTIVES

We sought to identify the characteristics that may predispose patients to develop supraventricular tachycardia (SVT) after ingestion of GoLYTELY (PEG 3350 and electrolytes oral solution) in anticipation for their colonoscopy.

METHODS

We performed a retrospective observational cohort study of the electronic medical record of all patients who developed SVT after ingestion of GoLYTELY solution from April 2012 to March 2019 at the John D. Dingell VA Medical Center. Clinical data were obtained through review of medical records.

RESULTS

We identified 16 patients with new-onset SVT after ingestion of bowel preparation solution before undergoing the colonoscopy procedure. In all, 12 (75%) patients developed atrial fibrillation, 3 (18.8%) patients developed atrial tachycardia, and 1 patient (6.3%) developed atrial flutter. Most patients were male (93.8%), and the mean age was 69 ± 8.2 years. The commonly associated comorbidities were hypertension (87.5%), hyperlipidemia (56.3%), and diabetes (37.5%). Laboratory testing demonstrated a normal electrolyte panel and thyroid stimulating hormone level. A significant percentage of patients had dilated atria and left-ventricular hypertrophy on echocardiogram.

CONCLUSION

Our case series suggests that there may be certain individuals who are predisposed to development of atrial arrhythmias, more so than others, after ingestion of PEG based solution for colonoscopy. We hypothesize that the combination of atrial dilation, sympathovagal discharge, and transient electrolyte shifts at the cellular level led to the development of SVTs.