Early ICD lead failure in defibrillator systems with multiple leads via cephalic access.

INTRODUCTION: Implantable cardioverter defibrillators (ICDs) are proven to prevent sudden death in patients at elevated risk for sustained ventricular tachycardia or fibrillation. Complications related to ICD failure can stem from lead dysfunction, manufacturing defects, patient characteristics, or implantation technique. We conducted a review of all ICD leads implanted at our center from 2011 to 2017 to determine risk factors for premature lead failure. METHODS: We conducted a retrospective review of patients of all ICD leads implanted from December 2011 to June 2017 at our institution. A total of 660 patients (Biotronik Linox S/SD, n = 281; Sprint Quatro, n = 207; Durata, n = 121; Endotak, n = 51) underwent ICD implantations. Patient and lead characteristics, procedural outcomes and complications were recorded. Lead failure was defined per Heart Rhythm Society lead-management consensus as a lack of procedural or clinical success, thus requiring an extraction of the lead. Patient and lead outcomes were recorded and variables associated with lead failure were assessed by the Kaplan-Meier method. RESULTS: Overall failure rate was similar for all leads: Linox S/SD-0.29%/year; Sprint Quattro-0.21%/year, Durata-0.39%/year and Endotak Reliance-0.0% (P = .769). No difference was found in overall survival when comparing all ICD manufacturers during the study period. Subgroup analysis revealed the risk of premature lead failure was particularly pronounced in multi-lead ICD systems implanted via cephalic access (P < .001). The estimated failure rate of Linox leads implanted via cephalic access in multi-lead systems was 19%/year. The estimated failure rate of non-Linox leads implanted via cephalic access in multi-lead systems was 11%/year. Neither age, nor gender were risk factors for lead failure in the Linox, or non-Linox cohorts. CONCLUSION: All analyzed ICD leads were found to have a similar overall risk of premature failure. ICD lead implantation via cephalic access in multilead ICD systems may be a previously unidentified risk factor for premature ICD lead failure, although these findings require further validation.

QT Prolongation and Clinical Outcomes in Patients with Takotsubo Cardiomyopathy.

BACKGROUND: Takotsubo cardiomyopathy (TCM) has been associated with repolarization abnormalities including QT prolongation and acquired long QT syndrome. However, the association between QT prolongation and clinical outcomes in patients with TCM remains unclear. The aim of this study is to examine the association between QT prolongation and ventricular arrhythmias, cardiogenic shock, and death in patients with TCM. METHODS: Forty-six patients with TCM met our inclusion criteria in an ongoing prospective cohort database from 2010 to May 2015. We assigned the patients to a long QT group or a normal QT group, and created a composite outcome consisting of ventricular arrhythmias, cardiogenic shock, or death. RESULTS: The mean age of the participants was 59.7 ± 16 years, 67% were women, and 63% had hypertension. Median follow-up time was 3.1 years (interquartile range: 2.0-3.8), with a total of 133.8 person-years. The mean left ventricular ejection fraction at diagnosis was 27.2% ± 1.4%. The mean QTc on diagnosis was 484 ms ± 10.2 ms for men, and 488 ms ± 8.6 ms for women. The long QT group had a 4.1-times higher odds of having the composite clinical outcome as compared to the normal QT group (95% confidence interval: 1.1, 16.1, P = 0.04) after adjusting for age and race in logistic regression. CONCLUSION: Patients with TCM who have a long QT interval or develop acquired long QT syndrome due to TCM may be more likely to be intubated; require vasopressors; and develop shock, ventricular arrhythmias, and death than those with a normal QT interval.

The Importance of Subclavian Angiography in the Evaluation of Chest Pain: Coronary-Subclavian Steal Syndrome.

Routine preoperative screening for the presence of brachiocephalic disease using ultrasonic duplex or angiography is a cost-effective and essential means to prevent the development of rare occurrences of coronary-subclavian steal syndrome.

Refractory Case of Paroxysmal Autonomic Instability With Dystonia Syndrome Secondary to Hypoxia.

Paroxysmal autonomic instability with dystonia (PAID) is a syndrome commonly related to traumatic brain injury (TBI) and rarely to anoxia associated with symptoms of dystonia, tachycardia, tachypnea, and diaphoresis. This is a case of a 20-year-old man who was stabbed in the heart. He underwent surgical repair of a ventricular septal defect and mitral valve replacement. Postoperatively, he developed dystonia with tachycardia and tachypnea consistent with PAID syndrome, secondary to prolonged hypoxia. Traditionally, this poorly understood syndrome is treated with morphine, clonazepam, and nonselective ß-blockers. Second-line medications commonly used are baclofen, dantrolene, and gabapentin, which are aimed at the dystonia itself. In this case, both first- and second-line agents were ineffective. A 72-hour dexmedetomidine infusion resulted in complete resolution of symptoms. This is the first case of anoxia-induced PAID syndrome to be effectively treated with dexmedetomidine, which was previously used in a case induced by TBI.