CARDIOVASCULAR JOURNAL OF AFRICA • Volume 34, No 2, May/June 2023 AFRICA 123 coronary angiogram are confirmatory. The role of provocative testing using exercise or saline loading during right heart catheterisation (RHC) or invasive cardiopulmonary stress test can help confirm the diagnosis in cases of diagnostic equipoise. The importance of excluding differential diagnosis such as infiltrative cardiomyopathies, hypertrophic cardiomyopathy (HCM), hypertensive cardiomyopathy, valvular heart disease, constrictive pericarditis and myocarditis was emphasised.10 A common but underappreciated presentation of HFpEF is patients with unexplained dyspnoea, and two clinically useful diagnostic scoring systems, the H2FPEF score and the HFA-PEFF may aid in the diagnosis of HFpEF.11,12 Treatment of HFpEF involves symptom management, defining the HFpEF phenotype, and treatment of associated co-morbidities. Lifestyle modification (exercise training, and weight loss for obese patients) is also important. For medical therapy, the efficacy of standard HFrEF GDMT is limited due to pathophysiological heterogeneity of HFpEF. BB may be tried for patients with concomitant AF and CAD; however, caution must be exercised with use as many of these patients have concomitant chronotropic incompetence. Decongestive therapies with loop diuretics are key but HFpEF patients are more prone to azotaemia. Other agents indicated for HFpEF include spironolactone (in selected patients) based on the TOPCAT trial and ARNI based on the PARAGON-HF trial.13,14 Empagliflozin is approved for HFpEF based on the strength of the EMPEROR-Preserved trial.15 Data from the DELIVER trial using dapagliflozin has shown similar benefits and will likely soon be approved for use in HFpEF.16 Cardiomyopathies: focus on HCM and cardiac amyloidosis A presentation on all cardiomyopathies was beyond the scope of the symposium and the presentation started with an overview of the cardiomyopathies such as genetic, mixed aetiology or acquired cardiomyopathies. Nigeria has the highest incidence of peripartum cardiomyopathy in the world, which is characterised by late presentation, high mortality rates and low rates of myocardial recovery.17 However, due to recent advances in management options, the focus was on HCM and restrictive cardiomyopathy [cardiac amyloidosis (CA)]. Hypertrophic cardiomyopathy HCM is the most common hereditary heart disease in the USA and affects persons regardless of age, gender or ethnicity.18,19 HCM is largely caused by dysfunction in the sarcomere, which may be due to genetic mutations but many patients with HCM lack pathogenic mutations. It is characterised by left ventricular hypertrophy (LVH), hypercontractility, impaired relaxation, increased energy consumption and reduced compliance. The pathophysiology of symptoms for HCM can be characterised by the presence or absence of dynamic narrowing of the LV outflow tract (LVOT), by the systolic anterior motion of the mitral valve, or in cases of severe LVH, by dynamic mid-cavity obliteration in systole. A LVOT gradient > 30 mmHg is diagnostic of obstruction. The natural history of HCM is characterised by clinical stability with normal longevity in most patients, but some patients have disease progression manifesting as symptoms of AF/stroke, sudden death, progressive HF, or ‘burnt out’ end-stage advanced HF. Treatment includes avoidance of dehydration and extreme physical activity, but moderate-level exercise as part of a healthy lifestyle is permissible. Traditional medical therapy includes BB or non-dihydropyridine calcium channel blockers such as verapamil or diltiazem and anticholinergic agents such as disopyramide. Mavacamten represents a new therapeutic option for obstructive HCM patients. In the phase 3 EXPLORERHCM trial, treatment with mavacamten improved exercise capacity (peak VO2 +1.4 ml/kg/min, 0.6–2.1; p = 0.0006), LVOT obstruction, New York Heart Association (NYHA) functional class, and health status in patients with obstructive HCM.20 The VALOR-HCM showed that in patients with obstructive HCM with severe symptoms, mavacamten significantly reduced the fraction of patients meeting guideline criteria for septal reduction therapy after 16 weeks.21 In the context of Nigerian patients, although genetic testing may play a role in family screening and identification of HCM phenocopies,22 we do not recommend this routinely. This is because identified mutations may have unclear significance and do not predict future risk of adverse clinical events, prognosis or sudden death. It is also expensive and can lead to genetic discrimination. Although mavacamten has beneficial effects, its cost to patients in SSA with limited health insurance coverage may make it logistically difficult to become the standard of care for HCM patients in SSA. Cardiac amyloidosis The presentation started by highlighting the high prevalence of CA, especially the isoleucine 122 (V122I) variant of transthyretin amyloidosis (ATTR) in patients of African ancestry.23-25 Variant transthyretin V122I has an autosomal dominant pattern of inheritance and is carried by 3.43% of blacks in the USA.25 It is associated with isolated cardiac involvement in patients over the age of 60 years, with male predominance (men:women in a ratio of 6:1).23 The gene frequency and implications of transthyretin ATTR V122I in West African populations such as Nigeria is unknown and needs to be better understood.26 This is an important unknown because the geographic emergence of the ATTR V122I is likely an initial mutation from West Africa. The Atlantic slave trade led to population dislocations that transported subjects to the Americas, Caribbean and parts of Western Europe. Cardiac ATTR V122I amyloidosis is a common but under-appreciated cause of HF in elderly (7th decade) patients of African origin, with persistent fluid overload despite diuretic use. Survival in ATTR V122I is poor.26 CA is a common cause of HFpEF and a high index of suspicion is required to confirm this diagnosis.27 The two major sub-types of CA are immunoglobulin light-chain, amyloid lightchain (AL) amyloidosis or transthyretin (TTR) amyloidosis (senile CA). Cardiac involvement manifests as HF (most common), AF, conduction disease, orthostatic hypotension and ventricular arrhythmias.28 Amyloid cardiomyopathy is a disease of diastole, and rapid rise of filling pressures leads to low end-diastolic volume and consequently reduction in stroke volume and reduced cardiac output. Compensatory tachycardia is often necessary to maintain cardiac output. Low systolic pressures (< 100 mmHg) are
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