History of Hypertrophic Cardiomyopathy (HOCM), with Tachycardia and High Lactate

A patient under 40 with h/o HOCM and implantable cardioverter-defibrillator (for secondary prevention of VF arrest that occurred during exertion) presented with chest pain, diaphoresis, and tachycardia.  Earlier in the day, the patient had been physically active, which resulted in dizziness, SOB and diaphoresis.  Then later, there was alcohol consumption associated with further physical exertion.  The patient presented clutching the chest, dizzy, SOB, diaphoretic.  BP was 165/109 (a good example of shock in which the BP is maintained by high systemic vascular resistance).Here is her ED ECG:There is a narrow complex (QRS duration =113 ms) tachycardia at a rate of about 160.  There are no definite P-waves.  It appears to be paroxysmal SVT.  There is very high voltage and secondary repolarization (ST-T) abnormalities.The Bedside Cardiac Ultrasound is shown here: This shows the very hypertrophic walls, and the consequent very small left ventricular chamber collapsing on itself.  There is very little opporunity for the heart to fill with blood, and probable obstruction of aortic outflow as well.The patient was given adenosine 6 mg, 12 mg, 12 mg, and 18 mg without any lasting effect. Lactate returned at 8.3 mEq/L, consistent with shock.Then an esmolol double bolus (each bolus = 500 mcg/kg) and drip was given, with immediate slowing of heart rate.  The patient was given a normal saline fluid bolus.The heart rate immediately slowed and her...
Source: Dr. Smith's ECG Blog - Category: Cardiology Authors: Source Type: blogs