Cardiac Memory-induced T-wave Inversions.

INTRODUCTION: Cardiac memory refers to T-wave inversions that result when normal ventricular activation resumes following a period of abnormal ventricular activation. CASE REPORT: We present a case of a 29-year-old man with a pacemaker who presented with new, deep symmetric T-wave inversions caused by cardiac memory. DISCUSSION: Abnormal ventricular activation is most commonly induced by ventricular pacing but can also occur in the setting of transient left bundle branch blocks, ventricular tachycardia, and intermittent ventricular pre-excitation. CONCLUSION: Recognition of this phenomenon may help to reduce unnecessary admissions, cardiac testing, and cardiac catheterizations.

Twiddler's Syndrome.

Twiddler's syndrome refers to a rare condition in which a pacemaker or automatic implantable cardioverter-defibrillator (AICD) malfunctions due to coiling of the device in the skin pocket and resultant lead displacement. This image is the chest radiograph (CXR) of a 54-year-old male who presented to the emergency department with chest pain five months after his AICD was placed. The CXR shows AICD leads coiled around the device and the absence of leads in the ventricle consistent with Twiddler's syndrome. Patients with twiddler's syndrome should be admitted for operative intervention.

Atrioventricular nodal reentrant tachycardia and cannon A waves.

Regular, narrow complex tachycardia with a ventricular rate around 150 can be challenging. The differential includes sinus tachycardia, atrioventricular nodal reentrant tachycardia (AVNRT), atrioventricular reentrant tachycardia (AVRT), and atrial tachycardia (focal or macro re-entrant - i.e. flutter). We present a case of a 90-year-old woman presenting with shortness of breath in which the ECG was not diagnostic, but the presence of regular neck pulsations helped secure the diagnosis of AVNRT. In AVNRT, atria and ventricular contractions occur nearly simultaneously. When the right atrium attempts to contract against a closed tricuspid valve, an abrupt increase in venous pressure is encountered. This increase in venous pressure manifests as prominent neck pulsations termed "cannon A waves." The patient was ultimately successfully electrically cardioverted resulting in resolution of her presenting symptoms, neck pulsations, and tachycardia. While irregular "cannon A waves" can be seen in conditions of AV dissociation, regular "cannon A waves" strongly favor the diagnosis of AVNRT.

A young female with urinary retention - Hashimoto's Encephalopathy.

Hashimoto's Encephalopathy (HE) is a rare form of autoimmune encephalopathy associated with Hashimoto's thyroiditis in which patients experience cognitive impairment and various neurologic symptoms. We present a case of a young female that presented to the emergency department with urinary retention, and was ultimately diagnosed with HE. Examination was significant for direction-changing and vertical nystagmus (direction-changing nystagmus describes a phenomenon where the fast beat changes with the direction of gaze), hyperreflexia, clonus, and Babinski and Hoffman's reflexes (all upper motor neuron (UMN) signs). Her symptoms improved with high dose intravenous steroid administration. To our knowledge, urinary retention in the presence of other UMN signs has not been reported in association with HE; nor has this patient's type of nystagmus. Emergency physicians should be aware of this condition and can play an important role by considering it when neurologic findings are not explained by infectious, toxic, metabolic, or structural etiologies. Although relatively rare, if detected and treated early HE can have a good prognosis.