Rare Paradoxical Response of Tachyarrhythmia to Adenosine Complicated by Novel ECG Artifact.

Adenosine is widely used for the diagnosis and treatment of supraventricular tachyarrhythmia. We report a rare case of adenosine use associated with the development of 1:1 atrial flutter with aberrancy. The diagnosis was further complicated by a newly described ECG artifact associated with Wireless Acquisition Module (WAMTM) ECG acquisition mimicking rhythm irregularity.

Unfortunately Fortunate: Self-Terminating Device-Initiated Tachyarrhythmia in a Patient With a History of Idiopathic Lead Migration.

An 88-year-old female presented with inappropriate implantable cardioverter-defibrillator shocks. Interrogation revealed lead noise sensed as ventricular fibrillation, leading to 11 shocks in 1 day. A defibrillation at the period of maximal vulnerability caused true ventricular fibrillation/ventricular tachycardia and additional shocks, which failed to terminate device-initiated tachyarrhythmia. The patient recovered spontaneously and the device was reprogrammed. (Level of Difficulty: Intermediate.).

Human Electrical Muscular Incapacitation and Effects on QTc Interval.

Human Electrical Muscular Incapacitation (HEMI) is used to subdue combative individuals. Changes in cardiac electrical activity have been proposed as the cause of death in a small fraction of these individuals. The current study sought to determine whether changes in QTc interval occur after HEMI exposure. Twenty-four participants had EKG readings before a 5-second HEMI exposure and within 30 min after exposure. All subject EKGs were read by a data-blinded cardiac electrophysiologist who calculated a QT corrected (QTc) interval. QTc interval was calculated using Bazett method. QTc prolongation was defined as >430 ms and a threshold of 30 ms for identifying QTc lengthening. Five participants experienced QTc prolongation and six had QTc lengthening. One participant developed QTc prolongation exceeding 500 ms, which carries a risk of developing multifocal ventricular tachycardia. These results suggest that HEMI exposure may cause EKG changes with a risk of ventricular tachycardia.

Management of central venous gradient using excimer laser lead extraction of chronic indwelling pacemaker leads in the setting of ipsilateral arteriovenous fistula.

Device therapy is becoming common in those patients with renal insufficiency. Coexisting need for arteriovenous (AV) fistula placement is often contemplated relative to device placement. We describe the excimer laser lead extraction of a malfunctioning chronic atrial pacemaker lead ipsilateral to an AV fistula.

Surface electrocardiography and histologic rejection following orthotopic heart transplantation.

BACKGROUND: Intraventricular conduction delay and QT interval dispersion may be related to electrical instability and the risk of ventricular arrhythmogenesis. The interlead variability of the QT interval on a surface 12-lead electrocardiogram (ECG) has been associated with an increased likelihood of sudden death in patients with long QT syndromes, in patients recovering from myocardial infarction, and dilated cardiomyopathy. We sought to determine the incidence of increased QT(c) dispersion (QT(c-d)) relative to biopsy grade of severity of rejection. METHODS: Records of patients having undergone orthotopic heart transplantation (OHT) were reviewed focusing specifically on surface ECGs performed in temporal proximity to endomyocardial biopsy. RESULTS: Seventy-five patients were evaluated on 1573 occasions, to include 999 surface ECGs, and 847 endomyocardial biopsies. There were 269 interpretable surface ECGs and endomyocardial biopsies performed within 1.1 +/- 4.6 days. There were no identifiable trends in atrioventricular or intraventricular conduction abnormalities (to include right bundle branch block) when comparing those with and without significant rejection on endomyocardial biopsy. The mean QT(c-d) of those with none (n = 34), mild (n = 194), moderate (n = 39), and severe (n = 2) rejection was 49 +/- 29, 49 +/- 35, 57 +/- 38, 81 +/- 7 ms, respectively (P = 0.28 by ANOVA of means). When comparing those with significant rejection so as to change management there was a trend toward increased dispersion (no to mild rejection, 49 +/- 34 ms vs moderate to severe rejection, 59 +/- 37 ms, P = 0.09). CONCLUSIONS: In this study investigating noninvasive ventricular depolarization/repolarization and correlation to histologic manifestation of rejection, there was suggestion, but no statistical significance, of QT(c-d) and severity of rejection. QT(c-d) should not be considered a sensitive marker for OHT rejection.