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BackgroundManagement of elderly patients with ST elevation myocardial infarction (STEMI) is challenging and they are under-represented in trials. Accordingly, we analysed reperfusion strategies and their effectiveness in patients with STEMI ≥75 years compared to <75 years within a comprehensive inclusive registry.MethodsConsecutive patients with STEMI admitted to hospital and tracked within a regional registry (2006–2011) were analysed comparing reperfusion strategy (primary percutaneous coronary intervention (PPCI), fibrinolysis and no reperfusion) between patients ≥75 vs <75 years old as well as across the reperfusion strategies in those ≥75 years.ResultsThere were 3588 patients with STEMI with 646 (18%) ≥75 years old. Elderly patients were more likely female (46.9% vs 18.4%) and had more prior: angina (28.2% vs 17.2%), myocardial infarction (MI; 22.8% vs 13.9%), hypertension (67.6% vs 44.2%), heart failure (2.3% vs 0.3%) and atrial fibrillation (2.2% vs 0.5%) (all p<0.001). The reperfusion strategy for patients ≥75 vs <75: PPCI 45.3% vs 41.2%, fibrinolysis 24.8% vs 45.7%, and no reperfusion 29.9% vs 13.1% (p<0.001). Time from symptoms to first medical contact (median, 93 vs 78 min p=0.008) and PPCI (median, 166 vs 136 min (p<0.001) were longer for ≥75 years. In those ≥75 years outcomes by reperfusion (PPCI, fibrinolysis and none) were: in-hospital death 13.3%, 9.4% and 19.7% (p=0.018), and composite of death, recurrent-MI, cardiogenic shock and congestive heart failure 28%, 20% and 33.2% (p=0.022).ConclusionsElderly patients have more comorbidities, worst in-hospital clinical outcomes and are less likely to receive reperfusion. Acknowledging physician selection of the reperfusion strategy; outcomes appear favourable in the elderly receiving fibrinolysis.

We appreciate the interest of Tang and colleagues, who have made substantial contributions to advancing care for patients with cardiac arrest. We provide additional information here to clarify the issues they raise, beginning with their last point.The letter expresses concern about an imbalance between groups 1 in the incidence of asystole as an initial rhythm. However, the multishock groups, on which the primary end point is based, are nearly balanced: 2 of 55 versus 0 of 51 patients initially in asystole.The letter expresses concern about aggregating first and subsequent shocks in the primary analysis. An abstract of our study reported separate results for subsequent shocks in which energy levels differ most between groups, revealing a larger advantage for higher-energy shocks: ventricular fibrillation termination, 71% for 150 J versus 85% for 300 to 360 J (Pϭ0.01); conversion, 24% versus 43% (PϽ0.01). 2 Another stated concern is that the automated external defibrillators studied were modified. They were not; study sites used their existing standard LIFEPAK 500 automated external defibrillators, providing protocol choices starting as low as 150 J and increasing to as high as 360 J. Although the Philips automated external defibrillators discussed by Tang and colleagues are limited to a fixed 150-J protocol, many automated external defibrillators allow various protocol choices, including 150 J fixed. Because most devices support multiple protocols and evidence to recommend 1 protocol over another remained lacking, our study addressed an important question: When multiple protocols are available, which should be chosen?The letter suggests that the lower peak current of the 150-J shocks we studied compared with different 150-J shocks discussed in the letter reduces defibrillation effectiveness. This would be true only if the waveform shape were the same. Compared with the 100-F shocks discussed in the letter, the longer time-constant 200-F shocks we studied provide higher average current for any given peak current. Consequently, as established in the literature, highercapacitance waveforms defibrillate with less peak current. 3 Most defibrillators increase energy by increasing shock intensity (current and voltage) rather than changing waveform shape or duration. We evaluated the effect of shock intensity without changing waveform and found that a protocol using higher intensities for subsequent shocks produced better heart rhythm outcomes than one maintaining a lower intensity. The principle demonstrated by our results would apply to any other waveform unless either (1) the first energy level succeeded for 100% of all shocks or (2) increasing the intensity above that of the first shock caused the peak current to exceed the level at which clinically significant myocardial injury appears. Multiple clinical studies report relatively low biphasic ventricular fibrillation termination rates (Ͻ75%) and subsequent shock success lower than the first shock success, providing ample evidence to rule out condition 1 for any def...

The standard definition appears equivalent to the definition using supplementary ECG codes to subcategorize patients with acute MI as having STEMI or non-STEMI. These findings may be relevant for the development of later versions of ICD codes.