Browsing by Author "Kraus, Sarah"

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    Correlation of signal-averaged electrocardiogram and late gadolinium enhancement cardiovascular magnetic resonance in the detection of myocardial fibrosis in arrhythmogenic right ventricular cardiomyopathy and other myocardial disorders
    (2021) Mgidlana, Msimelelo Mzwamadoda; Ntusi, Ntobeko; Kraus, Sarah
    Background. The diagnosis of fibrotic scar tissue in arrhythmogenic right ventricular cardiomyopathy (ARVC) and other cardiomyopathies is crucial as it forms the substrate for ventricular tachycardia (VT) and fibrillation (VT). Signal-averaged electrocardiography (SAECG) abnormalities are frequent in ARVC and in other cardiomyopathy-related ventricular arrhythmias. The correlation between cardiovascular magnetic resonance (CMR) late gadolinium enhancement (LGE) and parameters of SAECG in ARVC is not known. Method. Thirty-five patients [median age 32 years (IQR 25 – 46)] referred to the ARVC Registry at Groote Schuur Hospital were included in this retrospective study. SAECG was performed with high-amplification and filtered using bidirectional Butterworth filters between 40 and 250 Hz. A filtered averaged QRS (fQRS) was obtained and analysed for fQRS duration, low amplitude signal duration <40 mV (LAS40), and root-mean-square voltage in the last 40ms of the QRS (RMS40). LGE acquired at 5 to 20 minutes after intravenous administration of gadolinium (0.1mmol/kg to 0.2mmol/kg of body mass) was assessed. We evaluated the correlation between SAECG parameters and the presence of LGE. Results. Sixteen patients had definite ARVC, 5 had possible ARVC, 4 had idiopathic VT/VF, 2 had Athlete's heart, 1 had dilated cardiomyopathy (DCM), 1 had hypertrophic cardiomyopathy (HCM), 1 had SVT and 1 had pericardial constriction. LGE was present in 13 (81%) ARVC patients, 2 (40%) with possible ARVC, 1 (50%) with athlete's heart and in all patients with DCM and HCM. Patients with idiopathic VT/VF, pericardial constriction and supraventricular tachycardias had no myocardial LGE on CMR. Comparing patients with LGE and those without LGE on CMR, there were no differences in fQRS, (114ms [102.3 – 119] versus 111ms [99.5 -130], p = 0.608); LAS40 (34.5ms [16.8 - 40.8] versus 31ms [27.5 – 45], p = 0.566) and a RMS40 (23.5 µV [14.3 – 47.5] versus 33 µV [18.5 – 43.5], p= 0.621), respectively. LGE was present in 6 (60%) patients who had VT at presentation, in 9 (56%) with VT at baseline or follow-up and in all (2) patients who survived cardiac arrest. Three oneway analyses of variance (fQRS vs LGE, LAS40 vs LGE and RMS40 vs. LGE) confirmed that there was no correlation between LGE technique on CMR and SAECG for the detection of myocardial fibrosis in ARVC and other myocardial disorders: for fQRS F(1 , 33) = 1.47, p = 0.23,  2 = 0.02; for LAS40 F(1 , 33) =0.95, p = 0.34,  2 = 0.02 and for RMS40 F(1 , 33) = 0.36, p= 0.85,  2 = 0.02. Conclusion. In this study comparing assessment of myocardial fibrosis by LGE CMR and SAECG, there was no correlation between CMR and SAECG in detection of myocardial fibrosis in ARVC and other cardiovascular diseases.
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    Outcomes of patients with hypertensive heart disease and heart failure with reduced ejection fraction (HFrEF) at a tertiary centre in South Africa
    (2022) Boakye, Darlene; Kraus, Sarah; Ntusi, Ntobeko; Davidson, Bianca
    Introduction. Hypertension is endemic in Sub-Saharan Africa and has been shown to be the leading cause of heart failure (HF) on the continent. Clinical observation suggests that hypertensive heart disease (HHD) is potentially reversible with medical therapy and that baseline characteristics and outcomes differ from other causes of HF. Method. This was a single centre, retrospective hospital-based observational study of patients diagnosed with HF with reduced and mid-range ejection fraction (HFrEF and HFmrEF) secondary to HHD, seen at the Cardiomyopathy Clinic at Groote Schuur Hospital over a threeyear period. Ethics approval was obtained (HREC REF 677/2018). Results. A total of 59 patients were included, with an equal representation of both genders [female 49.2%]. The majority of patients were of mixed race [57.6%] and black African [39%] ethnicity. The mean age at presentation was 44 ±12.0 years. At baseline, 71.7% of patients had effort intolerance [NYHA Class II, 36.2%; Class III, 32.8%; Class IV, 1.7%] and the most common symptoms were dyspnoea [65.5%], pedal oedema [34.5%] and orthopnoea [29.3%]. A pre-existing diagnosis of hypertension was present in 66.8%, 30,5% had other comorbidities (HIV, 5 [8.5%]; diabetes mellitus, 5 [8.5%]; chronic kidney disease, 5 [8.5%]) and 62% of women presented in the peripartum period. At baseline, the mean systolic and diastolic blood pressures were 130±20.1 and 81±12.8mmHg, respectively. Congestive HF was observed in 40.7% of cases despite being on medical therapy (loop diuretics [88.5%]; ACE-I [88.5%]; beta blocker [84.6%]; MRA [51.9%]). Atrial fibrillation [3.5%] and LBBB [10.5%] were infrequent. Left ventricular hypertrophy (LVH) was noted in 54.4% on ECG, and the mean QTc was prolonged [466±35ms]. On echocardiogram, mean wall thickness was normal [IVSd 1.0 [0.9-1.2]; LVPWd 1.1 [0.8-1.3], however, left atrial [4.4±0.9cm] and LV end-diastolic dimensions [LVEDD 6.4±0.8cm] were increased. LV ejection fraction (EF) was markedly impaired [29.9±10.4%]. At follow up, there was a significant (p< 0.001). Recovery of LVEF was observed in 86.5% patients where repeat imaging was done [LVEF ≥ 50% in 45.9%; LVEF improved ≥10% in 40.5%]. 1- and 3-year transplant-free survival was 98.3% and 90.5%, respectively. Conclusion. Most patients with HHD and impaired LVEF have a pre-existing history of hypertension and present with effort intolerance, congestion and mildly elevated or ‘pseudonormal' blood pressures. Concentric LVH was not a prominent feature on echocardiogram and AF was infrequent. Despite severely impaired LVEF at baseline, mortality was lower than expected for HF patients and improvement in LVEF on therapy was observed in the majority of patients.
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    The Rationale, Design and Implementation of the African Cardiomyopathy and Myocarditis Registry
    (2019) Kraus, Sarah; Ntusi, Ntobeko; Mayosi, Bongani
    Background. Causes of heart failure in Africa are largely non-ischaemic: hypertension, rheumatic heart disease and cardiomyopathy. Cardiomyopathies pose a great challenge because of poor prognosis and high prevalence in low- and middle-income countries with limited access to specialised care. Little is known about aetiology or outcomes of cardiomyopathy in Africa. Method. The African Cardiomyopathy and Myocarditis Registry Program (IMHOTEP) is a pan-African multi-centre, hospital-based cohort study. It aims to describe the clinical characteristics, aetiology, genetics, management and outcome of cardiomyopathies in children and adults. Index patients were recruited as either incident (new) or prevalent (existing) cases, and family screening was conducted in selected cases. Several sub-studies were conducted at the initiating centre, including; outcome studies on prevalent cases incorporated into IMHOTEP, a cardiovascular magnetic resonance (CMR) study on incident cases, and a clinical genetics study on families. Results. The pilot phase was commenced in Cape Town (February 2015), followed by staggered initiation at 6 further sites. Over 600 index patients have been recruited to the registry to date. Preliminary data on the first 99 incident adult cases recruited at the initiating site, showed that dilated cardiomyopathy (DCM; n=67) was commonest, followed by hypertrophic (HCM; n=13), left ventricular noncompaction (LVNC; n=11), restrictive (RCM; n=4) and arrhythmogenic right ventricular (ARVC; n=4) cardiomyopathies. Cardiomyopathy occurred predominantly in mixed race (46%) and black (41%) Africans, and more frequently in females (54%). Mean age of presentation was 36.8 ±12.5 years. CMR performed in incident cases (67/99, 68%) proved diagnostically useful, however, acute myocarditis was only reported in one individual. In addition, prevalent cases with ARVC and DCM were enrolled from two existing studies at the initiating centre. Except for fewer (24%) genotype positive (PKP2 20%, CDH2 4%) individuals with ARVC (n=70), the baseline characteristics and diagnostic criteria were similar to what has been reported internationally. Transplant-free survival probability at 1-year, 5-years and 10-years was 98.5%, 90.7%, and 80.8% respectively in ARVC (median survival time 9.0 years) and there were no significant differences in survival between those with and without implantable cardioverter defibrillators [p=0.27]. In the prevalent DCM cohort (n=133), transplant-free survival probability was 93.4%, 82.2% and 73.1% at 1-year, 5-years and 10-years respectively, with a median survival time of 5.3 years. The age of onset (34.8 ±11.0 years) and death (41.5 ±9.6 years) were significantly younger in our DCM patients compared to European cohorts. Thirty-five families were recruited (16 genotype positive, 19 genotype unknown) with autosomal dominant inheritance observed in 94.3% families. Conclusion. IMHOTEP is the first multi-centre registry for cardiomyopathy in Africa. Preliminary data suggests an earlier age of onset compared to European cohorts and that DCM is the most common form of cardiomyopathy in South Africa. Molecular genetic analysis will provide vital and novel data on the genetic causes of cardiomyopathy in Africans.
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    The utility of the 1994 versus the revised 2010 Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) Task Force diagnostic criteria for identifying mutation-positive probands with ARVC
    (2021) Lukhna, Kishal; Ntusi, Ntobeko; Kraus, Sarah
    Background: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited cardiac disorder characterised by structural and functional abnormalities of the right ventricle with or without left ventricular involvement. In 1994, Task Force criteria (TFC) were proposed for the diagnosis of ARVC and were found to be highly specific but lacked sensitivity. In 2010, revised TFC were proposed to increase sensitivity and facilitate diagnosis in those with subtle phenotypes. Purpose: Many participants of ARVC registries have been enrolled using the 1994 TFC and not re-analysed using the 2010 TFC. We retrospectively compared the utility of both TFC for the diagnosis of mutation-positive probands in the IMHOTEP (The African Cardiomyopathy and Myocarditis Registry Program) study with the aim of identifying diagnostic changes that may have clinical impact. Method: 162 participants with the suspicion of ARVC were referred between May 2003 and May 2018 to our ARVC registry. 150 cases were reviewed using the same ECG and imaging data to fulfil both TFC, and were re-classified by a diagnostic panel at Groote Schuur Hospital, Cape Town. Results: Sixty-eight participants were diagnosed with ARVC by the diagnostic panel and included into the registry; 14/68 participants with ARVC were found to be mutation-positive. Eighty-two participants were found to have an alternative diagnosis or insufficient criteria and were excluded from the ARVC registry. Mutation-positive probands presented at a significantly younger age compared to the mutation-negative group (29 ± 14 years versus 39 ± 13 years, p=0.009), suggesting an earlier onset of ARVC. Common reasons for presentation in the mutation-positive cohort included palpitations (79%) and presyncope (64%), with Page 11 of 78 approximately twice the number of participants presenting with sustained ventricular tachycardia (VT) compared to mutation-negative participants (79% versus 47%, p=0.036). The diagnostic yield of the 2010 versus 1994 TFC (n=68) revealed more participants with a definite diagnosis, and less featuring in possible and no criteria categories. A 67% (n=8) change in diagnosis from 1994 borderline to 2010 definite, and an 88% (n=7) change from 1994 possible to 2010 borderline, were observed. Mutation-positive participants had a higher yield for definite ARVC when compared to mutation-negative participants. We subsequently analysed the contribution of each diagnostic modality at fulfilling TFC in our mutation-positive definite participants and found CMR contribution statistically significant, p=0.021. Conclusion: Our study found that mutation-positive probands were found to be younger, more likely to present with sustained VT, fulfilled a significantly larger number of major 2010 TFC than mutation-negative probands, and that the 2010 TFC for structural and repolarisation abnormalities were more useful in diagnosing ARVC compared to 1994 TFC. We found a significant evolution in classification between both TFC, suggesting that re-classification of participants recruited in traditional ARVC registries according to updated criteria is worthwhile.