Arthroprosthetic cobaltism and cardiomyopathy.

Cobaltism related to athroplasty implants has been anecdotally documented in at least six cases presenting with a combination of neurological, endocrine and cardiac symptoms with improvement in most symptoms after revision. Causality however has not been well established. This report documents the case of a 75 year-old male farmer who presents with possible cobalt cardiomyopathy from severe cobalt poisoning in the setting of arthroprosthetic cobaltism with symptomatic improvement upon revision of the hip.

Long-term longevity and clinical outcomes of Linox S/SD implantable cardioverter-defibrillator leads: a single-center experience.

PURPOSE: Since the introduction of the Biotronik Linox S/SD leads in 2006, there have been multiple reports of premature lead failure. The purpose of this study was to investigate the longevity of the Linox S/SD leads and to identify the possible predictors of lead failure in a single tertiary implant center. METHODS: We retrospectively reviewed patients who underwent implantation of Linox S/SD leads or Sorin Vigila 1CR/2CR leads (the same Linox S/SD leads marketed by Sorin) at our center. The cumulative lead survival was estimated using the Kaplan-Meier curve, and variables associated with lead failure were assessed by Cox proportional hazard model. RESULTS: A total of 187 patients (154 (82%) male) underwent Linox S/SD or Vigila 1CR/2CR implantation between 2007 and 2013. During follow-up with a median time of 75 months, nine lead failures were identified (4.8%). The mean and median times from lead implantation to lead failure were 70.7 ± 21 months and 64 (45-111) months, respectively. The cumulative survival probability for the Linox S/SD at 5 years was 97.1% and at 12 years was 90.3%. Non-physiological high-rate sensing was the most common type of lead failure in patients. In two-thirds of these patients, this led to inappropriate shock. We did not find any significant relationships between patients' clinical and procedural characteristics and lead failure. CONCLUSIONS: At our center, the 5-year lead survival of the Linox S/SD has been better than reports from other centers. The majority of lead failures presented as non-physiological high-rate sensing with subsequent inappropriate therapy.

Junctional ectopic tachycardia (JET).

Junctional ectopic tachycardia (JET) is a tachyarrhythmia arising from the atrioventricular node and His bundle area. Enhanced normal automaticity has been postulated as the mechanism of JET in the majority of patients. It is more common in children and can be seen as congenital or in postoperative settings. It is often a narrow complex tachycardia but can present as a wide complex tachycardia as a result of aberrant conduction. Its differentiation from other arrhythmias especially atrioventricular nodal reentrant tachycardia (AVNRT) can be challenging. Medical treatment of JET is difficult, and catheter ablation remains the mainstay of treatment in refractory cases with a high risk of atrioventricular block and recurrence.

Pacemaker-mediated arrhythmias.

Pacemakers can be directly involved in initiating or sustaining different forms of arrhythmia. These can cause symptoms such as dyspnea, palpitations, and decompensated heart failure. Early detection of these arrhythmias and optimal pacemaker programming is pivotal. The aim of this review article is to summarize the different types of pacemaker-mediated arrhythmias, their predisposing factors, and mechanisms of prevention or termination.

Stenotic flow reserve derived from quantitative coronary angiography has modest but incremental value in predicting functionally significant coronary stenosis as evaluated by fractional flow reserve.

BACKGROUND: Stenotic flow reserve (SFR) derived from quantitative coronary angiography (QCA) has been correlated with myocardial ischaemia as determined by pharmacological stress echocardiography. However, the diagnostic accuracy of SFR in predicting functionally significant coronary stenosis as assessed by the gold standard, fractional flow reserve (FFR), has not been previously characterised. METHODS: Patients who underwent coronary angiography and FFR assessment between January 2010 and February 2012 in a single tertiary centre were retrospectively assessed. QCA parameters such as minimal lumen diameter (MLD), lesion length, diameter stenosis (DS), SFR, turbulent resistance (TR) and Poiseuille resistance (PR) were assessed. Significant FFR was defined as FFR ≤0.8. The diagnostic accuracy of QCA parameters to predict significant FFR was assessed by independent t-test and receiver operator characteristic (ROC) curve. Statistical significance was defined as P value of <0.05. RESULTS: The study included 272 patients (age: 64±11, 70% males) and 415 vessels. There were 180 (43%) vessels which were FFR significant. The mean FFR value for all vessels was 0.81±0.11. On comparison of AUC for predicting significant FFR, SFR (AUC =0.76) had the highest diagnostic accuracy compared to PR (AUC =0.75), % DS (AUC =0.73), TR (AUC =0.69), MLD (AUC =0.71) and DS >50% (AUC =0.64). Using a retrospectively determined optimal cut-off value of 3.51, the sensitivity of stenotic-flow-reserve was modest at 56% with good specificity of 81%. DS >50% had a sensitivity of 47% and specificity of 82% in predicting significant FFR. There was incremental predictive value when SFR was added to DS >50% on integrated discrimination improvement index (IDI =0.103, P<0.001) and net reclassification index (NRI =0.72, P<0.001). CONCLUSIONS: SFR has modest diagnostic accuracy for predicting significant FFR but adds incremental predictive value to DS >50% for predicting significant FFR.

Anatomic characteristics and outcome of adults with coronary arteries arising from an anomalous location detected with coronary computed tomography angiography.

We sought to determine the anatomic characteristics of coronary arteries arising from an anomalous location (CAAL) detected on coronary computed tomography angiography (CTA) and assess the impact of high-risk anatomic characteristics on patient management and outcomes. We reviewed 9,774 consecutive CTA studies performed in adults between 2008-2013 and identified 114 with CAAL. CTA examinations were analysed to determine CAAL type, CAAL course (pre-pulmonary, interarterial, septal or retroaortic) and whether additional high-risk anatomic characteristics were present (luminal compression, intramural course, slit-like ostium and acute takeoff angle). Patients were contacted at mean 27.1-months to determine safety outcomes. The prevalence of CAAL was 1.14 % (114 of 9,974), with 36 (32 %) having anomalous right coronary artery from left coronary sinus, 71 (62 %) having anomalous left coronary artery from right coronary sinus and 7 (6 %) having a coronary artery arising outside coronary sinuses. Fifty-six patients (49 %) had ≥1 high-risk anatomic characteristic on CTA. Ten patients (9 %) underwent surgical intervention. Patients with high-risk anatomic features more frequently underwent functional testing (46 vs. 12 %, P = 0.01) and surgical intervention (14 vs. 3 %; P = 0.04) compared to patients without high-risk features. Patients undergoing surgery were more likely to have obstructive coronary disease on CTA than patients managed conservatively (50 vs. 13 %, P = 0.01). There was no cardiac death or ACS at follow-up (100 % complete). High-risk anatomic features on CTA in patients with CAAL more frequently lead to surgical management. Regardless of CAAL type, presence of high-risk anatomic characteristics or management strategy, the medium-term outcome of adults with CAAL is excellent.