CARDIOVASCULAR JOURNAL OF AFRICA • Volume 34, No 3, July/August 2023 150 AFRICA Clinical profile and outcomes of young patients treated with implantable cardioverter defibrillators at a South African tertiary hospital: a review of two decades of implantable cardioverter defibrillator implantation and follow up Philasande Mkoko, Kayla Solomon, Ashley Chin Abstract Aim: In young patients without atherosclerotic coronary artery disease, the aetiology of sudden cardiac death (SCD) has been described in Europe and North America. However, there are important regional variations and there are limited data on the aetiology and outcome of SCD in South Africa. The objective of this study was to determine the profile and outcomes of young patients treated with implantable cardioverter defibrillators (ICDs) at a South African tertiary hospital. Methods: This study was designed as a retrospective review of patients aged 35 years or younger implanted with ICDs at Groote Schuur Hospital. Results: During the study period, 38 patients younger than 35 years were implanted with ICDs. The mean (standard deviation) age at ICD implantation was 25.1 (7.6) years and 63.2% were male. A secondary-prevention ICD was implanted in 57.9% of the patient population, and primary prevention in the remaining 42.1%. Patients with secondary-prevention ICDs presented with ventricular tachycardia (59.1%), ventricular fibrillation (31.8%) and receipt of cardiopulmonary resuscitation but no recorded electrocardiograms (9.1%). Arrhythmogenic right ventricular cardiomyopathy (ARVC) was the leading cause of SCD in the secondary-prevention patient population (36.4%). Idiopathic dilated cardiomyopathy accounted for 50% of the primary-prevention patient population. After a median (interquartile range) follow up 32 (14–90) months, 7.9% died and 5.2% received a heart transplant; 42.1% of the study population received appropriate ICD shock therapies and 18.4% received inappropriate shock therapies. Conclusion: In this single-centre study from South Africa, ARVC and repaired congenital heart disease were the leading causes of SCD in patients younger than 35 years treated with secondary-prevention ICDs. Primary-prevention ICDs were frequently implanted for idiopathic dilated cardiomyopathy. Submitted 30/11/21, accepted 2/7/22 Published online 12/8/22 Cardiovasc J Afr 2023; 34: 150–156 www.cvja.co.za DOI: 10.5830/CVJA-2022-039 Cardiovascular diseases claim approximately 17 million lives globally each year. More than 75% of these deaths are in low- and middle-income countries and 25% are sudden cardiac deaths (SCD).1,2 SCD is defined as sudden and unexpected death occurring within an hour of the onset of symptoms or occurring in patients found dead within 24 hours of being asymptomatic and presumably due to a cardiac arrhythmia or haemodynamic catastrophe.2,3 In Europe and North America, SCD is reported to account for more than 350 000 deaths per year.4-6 Ventricular arrhythmias are an important cause of SCD. In 157 patients who suffered SCD while wearing a Holter monitor, de Luna and colleagues reported that 84% had ventricular tachycardia (VT) or ventricular fibrillation (VF) and 16% had a bradyarrhythmia as the cause of SCD.7 This finding has been confirmed in more contemporary data.8 Although SCD is uncommon in young adults, with an estimated annual incidence of one per 100 000 in people younger than 35 years of age, compared to one per 1 000 for those older than 35 years of age;4,9 SCD in young adults is emotionally overwhelming for families and the community. Implantable cardioverter defibrillators (ICDs) are well established as an important therapeutic intervention for the prevention of SCD by terminating ventricular arrhythmias in patients at risk of SCD or those who have survived SCD.10-14 Implantation of ICDs for primary and secondary prevention of SCD is supported by contemporary guidelines.2,3 However, access to ICDs in low- and middle-income countries is limited due to the high cost of these devices and the shortage of adequately trained physicians to select appropriate patients, implant the device, manage the complications and follow up the patients.15-17 Therefore there are limited data on the patient profile and outcomes of patients implanted with ICDs in sub-Saharan Africa. We performed a retrospective study to Division of Cardiology, Department of Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa Philasande Mkoko, MB ChB, MMed (UCT), MPhil (UCT), FCP (SA), Cert Cardio (SA), Mkkphi002@myuct.ac.za Ashley Chin, MB ChB, MPhil (UCT), FCP (SA), Cert Cardio (SA) Cardiac Clinic, Groote Schuur Hospital, Cape Town, South Africa Philasande Mkoko, MBC hB, MMed (UCT), MPhil (UCT), FCP (SA), Cert Cardio (SA) Kayla Solomon, BTech Ashley Chin, MB ChB, MPhil (UCT), FCP (SA), Cert Cardio (SA)
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