24-Hour Holter Monitoring at the Lagos State University Teaching Hospital –A Report of 85 Cases

Background The 24-hour Holter ambulatory ECG monitor is a device introduced over 2 decades ago, to monitor the electrocardiogram of patients throughout the day. It is able to document paroxysmal tachyarrhythmias that might be missed on a normal routine ECG recording. It has only been available in few centers in Nigeria over the last 5 to 10 years. The aim of this study is to evaluate the heart rate and rhythm pattern in patients who were referred for 24-hour ambulatory Holter ECG monitoring in LASUTH between January 2005 and June 2009. Method This is a retrospective study of 85 patients consisting of 41 males and 44 females, who were referred for 24-hour Holter ambulatory ECG monitoring in LASUTH between January 2005 and June 2009. After the Holter monitor was strapped to the subject’s waist, the subject was told to go home and continue with normal daily activities throughout period of the recording. They were also told to document the time of significant clinical events such as chest pain, palpitation, and dizzy spells during the period. They returned 24 hours later with the Holter monitor. The result was subsequently analyzed by the Cardioline scan and the result verified by the authors. Result The age range of patients referred for 24-hour Holter monitoring was between 13 and 72 years with a mean age of 44 ± 15years. The common indications for Holter monitoring in these patients were unexplained palpitation, dizzy spells, chest pain and syncopy. Rare indications include unexplained dyspnea on exertion and pace maker implantation. More than half of the study subjects (54 %) had documented episodes of severe tachycardia (HR ≥ 120bpm) while 18 patients had severe bradycardia (HR≤ 40 bpm). Twenty-one (21) patients were confirmed to have ventricular ectopics while 3 patients had non sustained ventricular tachycardia. Conclusion The 24-hour ambulatory Holter ECG monitor is a useful tool in evaluating patient presenting with unexplained palpitation, dizzy spells and syncopal attack. However, only a minority of such patients have documented and confirmed clinically significant tachyarrhythmias in this study. A subsequent larger prospective study would shed more light on this subject. Key Words: Electrocardiogram (ECG), 24-hour Holter, Heart Rate variability. Paroxysmal tachyarrhythmias.