The Practitioner Le praticien Country cardiograms case 27 : Answer

© 2005 Society of Rural Physicians of Canada Can J Rural Med 2005; 10 (3) T he situation described is a challenge for a lone emergency department physician practising in a remote area. Although tricyclics are no longer the first-line treatment for depression, they are still commonly used to treat conditions such as chronic pain syndromes and fibromyalgia. Overdose from tricyclics is therefore less commonly seen than in previous decades (they were introduced in the 1960s) but will continue to occur. If the estimated dosage and patient weight are correct, it is clear that complications can be expected from this potentially lethal overdose. Close and prolonged attention will need to be paid to seizure management, fluid balance, electrolyte balance, and alkalinization of serum pH. Airway control with assisted ventilation will likely be needed. Into this mix must be thrown the potential for significant cardiotoxiciy and dangerous arrythmias. Illustrated in the Question section (page 171) and repeated here, Figure 1 displays a regular wide-complex tachycardia, rate 139 beats/min, with QRS duration 0.14 seconds. P waves cannot be identified. There is no evidence of dissociated P waves, capture beats or fusion beats to “rule in” ventricular tachycardia. QRS morphology shows deep S waves in many leads, with some degree of concordance in precordial leads V1–V6. Significant right axis deviation is present, with axis in the 4th quadrant, of 200 degrees. Tall T waves are present. The Practitioner Le praticien