Author + information
- Mark Mariathas1,
- Cameron Gemmell2,
- Bartosz Olechowski1,
- Zoe Nicholas3,
- Michael Mahmoudi1 and
- Nick Curzen4
The introduction of highly sensitive troponin (HsTrop) assays into clinical practice has resulted in a significant increase in the frequency of type 1 (T1MI) & type 2 (T2MI) myocardial infarction (MI) diagnoses in clinical practice. The accurate differential diagnosis of T1MI & T2MI is essential in order to avoid inappropriate percutaneous revascularisation. The aims of this study were: (a) to describe the relative frequency of T2MI; (b) to describe the medium term mortality of T1 & T2MI in order to compare prognosis.
A retrospective analysis of consecutive patients with a primary discharge diagnosis of either tachyarrhythmia or non-ST elevated myocardial infarction (NSTEMI). Patients were classified as either T1MI or T2MI based on a review of their clinical records including ECG & troponin series. Statistical analysis was undertaken to compare the two groups.
A total of 704 patients were recruited (n=264 NSTEMI, n=440 arrhythmia). Forty-seven percent of tachyarrhythmia patients presented with elevated troponin above the 99th percentile (>40ng/L). There was no statistically significant difference in moratlity between NSTEMI and tachyarrhythmia troponin positive patients (Log rank p=.583). Of the total 704 cases, 470 were troponin positive. Of the latter, 240 (51%) patients were classified as T1MI and 230 (49%) as T2MI. T1MI patients had higher peak troponin values (4636ng/L Vs 899ng/L, p<.001), more coronary angiography (161(67%) Vs 32(14%), p<.001) and more revascularisation (91(57%) Vs 0(0%), p<.001). Patients were followed up for a median of 523 days and up to a maximum of 825 days. Kaplan Meier analysis showed mortality in T2MI patients was significantly worse (Log rank p=.011). Patients with T2MI driven by other illnesses had significantly higher mortality compared to patients with T2MI driven by arrhythmia (Log rank p<.001).
In patients presenting with primary arrhythmia, 47% have been shown to have an elevated troponin. This is higher than previously reported. In this study T2MI patients had an increased mortality compared to the T1MI group. Within the cohort classified as T2MI, patients with T2MI driven by other aetiologies had a worse mortality rate compared to those with T2MI driven by arrhythmia. These data can be used to help clinicians risk stratify T2MI patients before deciding on the appropriate management. Further data are now required.
CORONARY: Acute Myocardial Infarction