electrocardiogram ( ecg ) is an important diagnostic tool for the prompt recognition of myocardial infarction ( mi ) . identification of st elevation mi by ecg in the critically ill patient population is limited by the lack of specificity due to a variety of non - ischemic processes . this is a case report of a 77-year - old male patient who presented with generalized weakness , confusion , somnolence , recurrent falls and tea - colored urine for 3 - 4 days . his past medical history was significant for hypertension , chronic obstructive pulmonary disease and coronary artery disease with a remote history of mi . his vitals showed blood pressure 97/42 , heart rate of 51 , respiratory rate of 12 and oxygen saturation of 93% on room air . there were extensive ecchymoses in different stages of healing on all 4 extremities and on the torso . baseline electrocardiogram during admission to the hospital the patient was rehydrated with intravenous normal saline and nephrotoxic medications were withheld . his renal function improved and on the 2 day , his chest x - ray revealed patchy bilateral infiltrates . on the 3 day , he developed respiratory distress with an increase in oxygen requirements . the chest computed tomography revealed bilateral ground glass opacities with consolidation consistent with acute lung injury / acute respiratory distress syndrome . after failing a trial of non - invasive positive pressure ventilation , he was intubated and mechanically ventilated for hypoxic respiratory failure . he developed intermittent supraventricular tachycardia , atrial flutter and atrial fibrillation were treated with intravenous esmolol and diltiazem after which he converted to sinus rhythm . on the 4 hospital day , he developed increasing oxygen requirements and asynchronous volume control ventilation ; his ventilator settings were switched to pressure control ventilation . an echocardiogram revealed left ventricular ejection fraction of 45 - 50% with grade ii diastolic dysfunction and no wall motion abnormalities . he later became progressively hypoxic and tachypneic on the ventilator during the next couple of days . his clinical status worsened and his ventilator settings were changed ; the positive end - expiratory pressure ( peep ) was increased to 13 mm hg . ecg at the time showed st segment and t wave changes concerning for st elevation mi . careful review of the ecg revealed bizarre , broad - based apparent st - segment elevation in the precordial leads where the upward shift of the baseline started slightly before the onset of the qrs complexes . a more obvious dome and spike pattern was seen in the inferior leads [ figure 2 ] . his central venous pressure decreased from 12 to 7 mm hg and tidal volumes were increased from 550 to 750 cc during this period . an urgent bedside echocardiogram showed preserved left ventricular ejection fraction with no wall motion abnormalities . the patient passed away on the 11 day of hospitalization from acute respiratory distress syndrome . st - t segment changes of precordial leads after increase in positive end - expiratory pressure to 13 mm hg . german military helmet with dome and spike ( inset ) reproduced with permission from mayo clinic proceedings resolution of st - t segment changes in precordial leads after the discontinuation of positive end - expiratory pressure our case represents an uncommon finding of dome and spike st - t wave changes mimicking st elevation mi in the setting of a critical non - cardiac illness . these findings were similar to those reported by littmann and monroe and tomcsnyi et al . the st - t wave changes in these cases were likened to a spiked german military helmet [ inset figure 2 ] the  pickelhaube ,  introduced in 1842 by friedrich wilhelm iv , the king of prussia . the mechanism of this phenomenon is unknown and several postulated mechanisms for this finding include ( 1 ) artifact ( 2 ) a sudden increase in the intra - abdominal or intra - thoracic pressure ( 3 ) direct stimulation of inferior wall of left ventricle by the diaphragm , ( 4 ) stimulation of the diaphragm by the left phrenic nerve , ( 5 ) synchronized contraction of diaphragm along with the cardiac cycle in the setting of alkalosis with latent tetany , ( 6 ) acute stretch of skin overlying the chest wall with each cardiac cycle and ( 7 ) diaphragmatic breathing that alters ecg patterns . the acute rise in intrathoracic pressure with an increase in peep most likely contributed to the dome and spike pattern in our patient . this abnormal ecg finding with a dome and spike  helmet sign  pattern in a critically ill patient is a marker for very high mortality . it is an under - recognized phenomenon and further research is needed as early recognition can possibly assist clinical management .