Cardiac sarcoidosis diagnosed after orthotopic heart transplantation and clinically mimicking arrhythmogenic right ventricular cardiomyopathy.

Described herein is a 71-year-old man who underwent orthotopic heart transplant (OHT) for chronic severe heart failure secondary to cardiac sarcoidosis (CS) devoid of non-caseating granulomas but nevertheless characteristic of CS. Clinically, his heart disease had suggested the presence of arrhythmogenic right ventricular cardiomyopathy.

Flecainide toxicity late after liver transplantation.

Flecainide is an antiarrhythmic agent indicated for patients with supraventricular arrhythmias without ischemic or structural heart disease. Flecainide toxicity is a rare condition in which patients may present with bradycardia, widening of QRS, PR prolongation, ventricular tachycardia, syncope, malaise, dizziness, visual disturbance, nausea, vomiting, and/or lethargy. It carries an associated mortality rate of approximately 10%. Herein, we describe the course of a patient who experienced flecainide toxicity in the setting of renal and liver failure.

Brugada ST elevation masquerading as ST elevation myocardial infarction.

Brugada syndrome (BS) is a genetic cardiac syndrome first described in 1992 that is characterized by distinct abnormalities noted in leads V1 and V2 on electrocardiogram. It often leads to syncope or even sudden death in affected patients due to its propensity for ventricular tachycardia and fibrillation. The characteristic ST elevation seen in these patients can be confused with ischemic ST elevation. We present a case where a febrile illness unmasked BS and the ST changes seen were believed to be ischemic.

Analysis of electrocardiographic intervals before and after transcatheter aortic valve implantation to predict the need for permanent pacing.

Transcatheter aortic valve implantation (TAVI) is growing in utilization in the USA, and atrioventricular heart block is a common complication of the procedure. In patients with conduction system changes following TAVI, there are no clear guidelines for permanent pacing, leading to difficult clinical decisions on how long to leave temporary transvenous pacemakers in place. The aim of our study was to determine whether changes in electrocardiogram characteristics could predict the need for permanent pacing. A retrospective analysis was conducted of 209 consecutive TAVI patients seen from January 2012 to December 2015 at Baylor Heart and Vascular Hospital, Dallas. The baseline characteristics were similar between those who received a permanent pacemaker (PPM) within 7 days of the procedure (21.1%) and those who did not (78.9%); of those who did receive a PPM, 79.5% were implanted for complete heart block. The median (range) percentage change in the sum of QRS and PR was significantly higher in those who received a PPM (20.2%) than those who did not (7.1%) (P = 0.004). Using the percentage change in the sum of QRS and PR to predict PPM, the area under the curve was found to be 0.69. The optimal cutpoint was found to be 18.9% (sensitivity = 0.63, specificity = 0.73). Our study suggests that delay in the conduction system immediately following TAVI predicts the need for permanent pacing.

Takotsubo cardiomyopathy in the setting of complete heart block.

Few cases of coincident takotsubo cardiomyopathy and complete heart block (CHB) have been reported. A 62-year-old woman presented with typical chest pain and was found to have CHB with a left ventricular ejection fraction of 35% and apical ballooning on ventriculogram. The patient was transvenously paced and a permanent biventricular pacemaker was placed when the CHB did not resolve. Repeat echocardiography 15 days after the event showed the ejection fraction to be 50%. This case highlights management strategies in this unique situation.

Use of Oral Anticoagulation in the Management of Atrial Fibrillation in Patients with ESRD: Pro.

Warfarin has had a thin margin of benefit over risk for the prevention of stroke and systemic embolism in patients with ESRD because of higher bleeding risks and complications of therapy. The successful use of warfarin has been dependent on the selection of patients with nonvalvular atrial fibrillation at relatively high risk of stroke and systemic embolism and lower risks of bleeding over the course of therapy. Without such selection strategies, broad use of warfarin has not proven to be beneficial to the broad population of patients with ESRD and nonvalvular atrial fibrillation. In a recent meta-analysis of use of warfarin in patients with nonvalvular atrial fibrillation and ESRD, warfarin had no effect on the risks of stroke (hazard ratio, 1.12; 95% confidence interval, 0.69 to 1.82; P=0.65) or mortality (hazard ratio, 0.96; 95% confidence interval, 0.81 to 1.13; P=0.60) but was associated with increased risk of major bleeding (hazard ratio, 1.30; 95% confidence interval, 1.08 to 1.56; P<0.01). In pivotal trials, novel oral anticoagulants were generally at least equal to warfarin for efficacy and safety in nonvalvular atrial fibrillation and mild to moderate renal impairment. Clinical data for ESRD are limited, because pivotal trials excluded such patients. Given the very high risk of stroke and systemic embolism and the early evidence of acceptable safety profiles of novel oral anticoagulants, we think that patients with ESRD should be considered for treatment with chronic anticoagulation provided that there is an acceptable bleeding profile. Apixaban is currently indicated in ESRD for this application and may be preferable to warfarin given the body of evidence for warfarin and its difficulty of use and attendant adverse events.

Predictors for atrial fibrillation detection after cryptogenic stroke: Results from CRYSTAL AF.

OBJECTIVE: We assessed predictors of atrial fibrillation (AF) in cryptogenic stroke (CS) or transient ischemic attack (TIA) patients who received an insertable cardiac monitor (ICM). METHODS: We studied patients with CS/TIA who were randomized to ICM within the CRYSTAL AF study. We assessed whether age, sex, race, body mass index, type and severity of index ischemic event, CHADS2 score, PR interval, and presence of diabetes, hypertension, congestive heart failure, or patent foramen ovale and premature atrial contractions predicted AF development within the initial 12 and 36 months of follow-up using Cox proportional hazards models. RESULTS: Among 221 patients randomized to ICM (age 61.6 ± 11.4 years, 64% male), AF episodes were detected in 29 patients within 12 months and 42 patients at 36 months. Significant univariate predictors of AF at 12 months included age (hazard ratio [HR] per decade 2.0 [95% confidence interval 1.4-2.8], p = 0.002), CHADS2 score (HR 1.9 per one point [1.3-2.8], p = 0.008), PR interval (HR 1.3 per 10 milliseconds [1.2-1.4], p < 0.0001), premature atrial contractions (HR 3.9 for >123 vs 0 [1.3-12.0], p = 0.009 across quartiles), and diabetes (HR 2.3 [1.0-5.2], p < 0.05). In multivariate analysis, age (HR per decade 1.9 [1.3-2.8], p = 0.0009) and PR interval (HR 1.3 [1.2-1.4], p < 0.0001) remained significant and together yielded an area under the receiver operating characteristic curve of 0.78 (0.70-0.85). The same predictors were found at 36 months. CONCLUSION: Increasing age and a prolonged PR interval at enrollment were independently associated with an increased AF incidence in CS patients. However, they offered only moderate predictive ability in determining which CS patients had AF detected by the ICM.

Syncope secondary to second-degree atrioventricular block with donepezil use.

Donepezil, an acetylcholinesterase inhibitor, is approved for the treatment of mild to moderate dementia secondary to Alzheimer's disease. Although most prescribers are aware of the common gastrointestinal side effects of donepezil, cardiovascular side effects are rarely observed. Cardiovascular side effects of donepezil have almost always been observed in patients with a history of conduction defects or sick sinus syndrome. We report a case of a woman with early onset Alzheimer's disease and no history of cardiac disease who developed second-degree heart block after a few weeks of therapy with donepezil. Withdrawal of donepezil led to resolution of the atrioventricular block.

Drug-induced QT interval prolongation: mechanisms and clinical management.

The prolonged QT interval is both widely seen and associated with the potentially deadly rhythm, Torsades de Pointes (TdP). While it can occur spontaneously in the congenital form, there is a wide array of drugs that have been implicated in the prolongation of the QT interval. Some of these drugs have either been restricted or withdrawn from the market due to the increased incidence of fatal polymorphic ventricular tachycardia. The list of drugs that cause QT prolongation continues to grow, and an updated list of specific drugs that prolong the QT interval can be found at www.qtdrugs.org. This review focuses on the mechanism of drug-induced QT prolongation, risk factors for TdP, culprit drugs, prevention and monitoring of prolonged drug-induced QT prolongation and treatment strategies.

Unusual origin of type 1 atrioventricular block with comments on Wenckebach's contribution.

We present a case that demonstrates the rare occurrence of type 1 second-degree atrioventricular block (Wenckebach or Mobitz type 1 block) as a result of block in the infranodal conduction system. This extremely rare occurrence often predicts progression to complete heart block and necessitates cardiac pacing. It also demonstrates the value of an electrophysiological study and exercise stress testing to identify the level of block, predict prognosis, and plan a management strategy.

Causes and management of drug-induced long QT syndrome.

Long QT syndrome (LQTS) is characterized by inherited or acquired prolonged QT interval on the surface electrocardiogram. This can lead to torsade de pointes ventricular tachycardia (TdP VT) and ventricular fibrillation. In the acquired form of the disease, medications from several classes can cause TdP VT or potentiate the electrocardiographic findings. These include class IA and III antiarrhythmics, antibiotics (macrolides and quinolones), antidepressants (tricyclics and selective serotonin reuptake inhibitors), antipsychotics (haloperidol and phenothiazines), and antiemetics (ondansetron and prochlorperazine). We present four cases of drug-induced LQTS resulting in life-threatening cardiac arrhythmias. Antiarrhythmic medications were the cause in two cases, and the other two cases involved noncardiac medications. All four patients had at least one risk factor for LQTS in addition to the offending drug, including female gender, hypokalemia, hypomagnesemia, and bradycardia. In one patient, amiodarone was administered for treatment of VT, although the correct diagnosis was actually TdP VT. In patients with polymorphic VT or ventricular fibrillation without a significant history of cardiovascular disease, drug-induced LQTS should be high in the differential diagnosis. Prompt diagnosis is key, as amiodarone, while often used to suppress VT, is potentially harmful in the setting of LQTS and TdP VT.

Usefulness of percutaneous balloon mitral commissurotomy in preventing the development of atrial fibrillation in patients with mitral stenosis.

A prospective cohort of patients with mitral stenosis and no history of atrial arrhythmias showed no decrease in the incidence of atrial fibrillation (AF) after successful versus unsuccessful Inoue balloon percutaneous balloon mitral valve commissurotomy. Advanced age and left atrial dimension best predicted which patients developed AF during follow-up, whereas percutaneous balloon mitral valve commissurotomy procedural success and left atrial pressure reduction did not have an impact on incidence of AF.

Optimal duration of monitoring in patients with unexplained syncope.

The optimal duration of monitoring of patients with recurrent unexplained syncope who undergo prolonged monitoring with an implantable loop recorder is unknown. We examined the probability of syncope in a group of 167 patients with this condition who underwent prolonged monitoring with an implantable loop recorder. A 12-month monitoring period appears to capture >90% of episodes. Syncope is most likely to occur in younger patients with less heart disease and more frequent syncope. There is a low risk of syncope after 1 year of monitoring without an event.