Urgent considerations

See Differentials for more details

Cardiac ischaemia

The presentation of new-onset heart failure with dyspnoea and chest pain should alert the physician to ischaemia as a possible cause. Investigations include an ECG, and measurement of cardiac markers (e.g., troponins).[73][74]​​

Treatment should address immediate coronary reperfusion with either thrombolytic therapy or primary percutaneous coronary intervention to restore coronary blood flow. In addition, the implantation of an intra-aortic balloon may be warranted for immediate stabilisation. Heart failure is a common consequence of myocardial ischaemia, and requires emergency evaluation and intervention; however, it is important to note that the term 'ischaemic cardiomyopathy' is no longer recommended by the authors of the American Heart Association scientific statement.[1]

Hypertrophic cardiomyopathy

Initial presentation may be with syncope or sudden cardiac death, thus highlighting the importance of early diagnosis and screening of first-degree relatives. Physical examination may reveal an outflow murmur similar to aortic stenosis, which may be differentiated by Valsalva, handgrip, and squatting manoeuvers. Treatment involves avoidance of diuresis, which is in contrast to the management of other cardiomyopathies. In addition, beta-blockers and/or calcium channel blockers are indicated and strenuous exercise prohibited (aimed at preventing sudden death). Anti-arrhythmic agents and devices may be required in patients with serious cardiac arrhythmias or multiple risk factors for sudden death. See Hypertrophic cardiomyopathy.

Sudden death in young individuals (<40 years)

Sudden cardiac death is of major public health importance.[75] However, most of these sudden deaths occur in older individuals and are secondary to coronary heart disease. The sudden, unexpected cardiac death of a young individual has profound effects not only for the family and friends but also for society in general. Accurate figures are not available but it has been estimated that the incidence of sudden death in young individuals is about 1 in 100,000 per year.[76][77]

Common causes of sudden cardiac death include various types of cardiomyopathies and channelopathies, as well as atherosclerotic coronary artery disease, aortic dissection, and anomalous coronary arteries. Inherited cardiomyopathies are a significant cause of sudden cardiac death across all age groups. Individuals with inherited cardiomyopathies are frequently asymptomatic and may only be diagnosed incidentally or following family screening.​[5]

In up to 31% of cases of sudden cardiac death, no structural abnormality can be detected at postmortem.[78] In many cases a definitive diagnosis is not established at postmortem, despite there being a clear hereditary basis. Although it may be diagnostically challenging, it is very important to try to establish an accurate cause of death. Therefore, clinical investigation, and where indicated, genetic testing, of surviving family members is warranted.​[5]

Myocarditis

Two scenarios describe the most common presentations of fulminant myocarditis and giant-cell myocarditis:​[45]

  • Unexplained new-onset heart failure <2 weeks duration in association with a normal size or dilated left ventricle (LV) and haemodynamic compromise

  • Unexplained new-onset heart failure of 2 weeks to 3 months duration in association with a dilated LV and evidence of ventricular arrhythmias or high-degree atrioventricular block or a failure to respond to usual care within 1 to 2 weeks.

Cardiac magnetic resonance imaging (MRI) may provide an additional diagnostic tool as studies have shown a good correlation between active regions of myocarditis and areas of abnormal signal intensity on MRI.[13]

After establishing a diagnosis, patients with myocarditis require treatment of the systolic dysfunction (using standard heart failure treatments) and associated arrhythmic complications, which include strategies to manage both brady- and tachyarrhythmias. If the patient develops haemodynamic compromise, insertion of an intra-aortic balloon pump or use of a ventricular assist device may be required. Discussion with a cardiac centre that offers mechanical support and/or transplantation should take place at an early stage. The evidence base for use of specific antiviral therapies and/or immunosuppression is very limited. However, patients with giant cell myocarditis and eosinophilic myocarditis generally respond to immunosuppression, and this is one of the major reasons for undertaking endomyocardial biopsy in certain patient subsets. If in doubt, advice from experts in the management of myocarditis should be sought.[44]​​​​[45] See Myocarditis.​

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