Methamphetamine is the third most commonly abused drug in the world after cannabis and opioids with 34 million global users in 2016.1 Terms for amphetamine include speed, meth, crystal, crystal meth, glass, shards, ice, and tic. In New Zealand, it is commonly known as ‘P’. In the recent New Zealand Health Survey report 1.1% of adult New Zealanders admitted to methamphetamine use in the past year.2 Cardiac toxicity from methamphetamine use is an increasingly recognized entity in the modern era. Patients may present with cardiomyopathy, hypertension, arrhythmias, sudden cardiac death, acute coronary syndrome, vascular dissection, and stroke or pulmonary hypertension.3–5 Possible pathophysiological mechanisms for Buy meth online -associated cardiomyopathy (MAC) include direct myocardial toxicity, vasospasm, hypertension, mitochondrial injury, and free-radical formation
Our group has previously published the largest MAC cohort to date in Australasia, and one of the largest internationally, evaluating the clinical characteristics and outcomes of these patients.6 Patients with MAC were often young men of New Zealand Māori descent and from socioeconomically deprived areas. They presented acutely unwell with heart failure and significant left ventricular (LV) impairment. The LV remained significantly dilated and remodeled despite a small improvement in LV ejection fraction (EF) on serial follow-up imaging. The long-term prognosis was poor with a high mortality rate. Readmission with decompensated heart failure was common, and frequently due to non-compliance with treatment. However, evidence to guide management of this group of patients and understanding its outcomes, and how it differs from other cardiomyopathies, remain limited. This study aims to describe the clinical features, course, and outcome of MAC, and compared with a contemporary, age-matched cohort of patients with non-ischaemic cardiomyopathy (NCM).
Methods
Patient population
Patients admitted to Middlemore Hospital (Auckland, New Zealand) with symptoms and signs of heart failure according to Framingham criteria and with echocardiographic evidence of dilated cardiomyopathy with reduced ejection fraction were retrospectively identified between January 2005 and January 2019. Patients were included if they had a documented history of either current or past methamphetamine use and methamphetamine was thought to be an important contributing factor to their cardiomyopathy after initial investigations. The index admission was the first presentation with heart failure to our institution. Demographic, past history, laboratory, echocardiographic and angiographic data of the study population were obtained as previously described.6 The New Zealand Deprivation (NZDep) Index was used as a measure of socioeconomic deprivation.7
NCM cohort
The Heart Failure registry, as part of the All-New Zealand Acute Coronary Syndrome Quality Improvement (ANZACS-QI) registry, prospectively collects patients admitted with heart failure to Middlemore Hospital.8 Patients with a diagnosis of cardiomyopathy (history of heart failure symptoms and signs, and LVEF<50%) not related to ischaemic heart disease, methamphetamine, alcohol, or other recreational drugs with the first presentation of heart failure between January 2005 and January 2019 were randomly selected. This group was matched to the MAC group in terms of numbers, the age range of 20–65 years old, and year of diagnosis.
Outcomes
The primary outcome was mortality in MAC patients during the follow-up period until 31 January 2019. In-hospital complications defined as cardiogenic shock and/or use of inotropes, endotracheal intubation, and ventilation, acute renal failure requiring renal replacement therapy, and death were recorded. Other follow-up outcomes collected include myocardial infarction, stroke, and resuscitated cardiac arrest. Readmissions due to heart failure or any cardiovascular causes were recorded. The latest transthoracic echocardiogram results were also collected and reduced in severity by one or more categories (normal, mild, moderate or severe) from the initial echocardiogram for LV and right ventricular (RV) dimension and LVEF were recorded. Cardiology clinic attendance is also collected.
