Incessant tachycardia in a patient with advanced heart failure and left ventricular assist device: What is the mechanism?

AbstractWe present a case of incessant wide-complex tachycardia in a patient with left-ventricular assist device, and discuss the differential diagnosis with an in-depth analysis of the intracardiac tracings during the invasive electrophysiologic study, including interpretation of the relative timing of the fascicular signals during tachycardia and in sinus rhythm, and interpretation of pacing and entrainment maneuvers

Defining the substrate for ventricular tachycardia ablation: The impact of rhythm at the time of mapping

BACKGROUND: Voltage mapping is critical to define substrate during ablation. In ventricular tachycardia, abnormal potentials may be targets. However, wavefront of activation could impact local signal characteristics. This may be particularly true when comparing sinus rhythm versus paced rhythms. We sought to determine how activation wavefront impacts electrogram characteristics. METHODS: Patients with ischemic cardiomyopathy, ventricular tachycardia, and without fascicular or bundle branch block were included. Point by point mapping was done and at each point, one was obtained during an atrial paced rhythm and one during a right ventricular paced rhythm. Signals were adjudicated after ablation to define late potentials, fractionated potentials, and quantify local voltage. Areas of abnormal voltage (defined as \u3c1.5 mV) were also determined. RESULTS: 9 patients were included (age 61.3 ± 9.2 years, 56% male, mean LVEF 34.9 ± 8.6%). LV endocardium was mapped with an average 375 ± 53 points/rhythm. Late potentials were more frequent during right ventricular pacing (51 ± 21 versus 32 ± 15, p \u3c 0.01) while overall scar area was higher during atrial pacing (22 ± 11% vs 13 ± 7%, p \u3c 0.05). In 1/9 patients, abnormal potentials were seen during a right ventricular paced rhythm that were not apparent in an atrial paced rhythm, ablation of which resulted in non-inducibility. CONCLUSION: Rhythm in which mapping is performed has an impact on electrogram characteristics. Whether one rhythm is preferable to map in remains to be determined. However, it is possible defining local signals during normal conduction as well as variable paced rhythms may impart a greater likelihood of elucidating arrhythmogenic substrate

Dual chamber pacing mode in an atrial antitachycardia pacing device without a ventricular lead – A necessary evil

We present a case of a single chamber atrial pacemaker implanted for sinus node dysfunction and treatment of macroreentrant atrial tachycardias with atrial antitachycardia pacing. The patient presented with sustained atrial tachycardia above the detection rate, however, the device was unable to detect the tachycardia and did not deliver the programmed therapy. We discuss the nuances of the atrial tachyarrhythmia detection algorithms, and the programming strategies to maximize detection of atrial arrhythmias in a single chamber atrial pacemaker

Coincidental impact of transcatheter patent foramen ovale closure on migraine with and without aura — A comprehensive meta-analysis

Background: We analyzed the literature to assess the coincidental impact on migraines of transcatheter patent foramen ovale (PFO) closure performed for secondary stroke prevention. Methods: We searched Medline, EMBASE, and the Cochrane database for studies published up until August 2013. We included English-language studies that provided information on complete resolution or improvement in migraine headaches following PFO closure. Two study authors identified 375 original articles and both independently reviewed 32 relevant manuscripts. Data including study methodology, inclusion criteria, PFO closure and migraine outcomes were extracted manually from all eligible studies. Pooled odds (and probability) of resolution or improvement of migraine headaches were calculated using random-effects models. Results: Twenty studies were analyzed. Most were uncontrolled studies that included a small number of patients with cryptogenic stroke who had undergone PFO closure and had variable time of follow-up. The probability of complete resolution of migraine with PFO closure (18 studies, 917 patients) was 0.46 (95% confidence interval 0.39, 0.53) and of any improvement in migraine (17 studies, 881 patients) was 0.78 (0.74, 0.82). There was evidence for publication bias in studies reporting on improvement in migraines (Begg's p = 0.002), but not for studies on complete resolution of migraine (p = 0.3). In patients with aura, the probability of complete resolution of migraine post-PFO closure was 0.54 (0.43, 0.65), and in those without aura, complete resolution occurred in 0.39 (0.29, 0.51). Conclusions: Among patients with unexplained stroke and migraine undergoing transcatheter PFO closure, resolution of headaches occurred in a majority of patients with aura and for a smaller proportion of patients without aura

Shoulder Joint Dislocation as an Unusual Complication of Defibrillation Threshold Testing Following Subcutaneous Implantable Cardioverter-Defibrillator Implantation

A 53-year-old man underwent implantation of a totally subcutaneous ICD (S-ICD; Boston Scientific). He was positioned supine, with the left arm abducted, externally rotated (i.e. palm up) and strapped to the arm extender. The generator was placed in the left mid-axillary line along the 5th-6th intercostal spaces and the defibrillation coil was tunneled anterior to the sternum. Defibrillation threshold (DFT) testing with 65 Jcaused a forceful pectoralis twitch. The patient woke up with a painful anteriorly dislocated left shoulder. Glenohumeral dislocation due to DFT testing has not been previously reported. It is likely that this complication is specific to the S-ICD implantation, and is related to positioning with the arm abducted, externally rotated, and immobilized, and use of greater defibrillation energy with current pathway through the bulk of the pectoralis muscle.Precautions may include extending the arm palm down, strapping the arm loosely, and adduction of the arm for DFT testing