Makkar, Nayani

AbstractBackgroundImplantable loop recorders (ILRs) are effective in achieving symptom‐rhythm correlation. However, diagnostic yield in routine clinical practice is not well established.MethodsPatients undergoing ILR implantation between April 2010 and May 2015 were included. All devices were enrolled in remote monitoring with automatic arrhythmia detection and P sense algorithms switched “ON.” Symptom‐rhythm correlation was assessed and changes in management were recorded.ResultsA total of 312 patients (57% male, age 53 ± 22 years; median CHADS2VaSc score = 1) were included in this study. ILRs were implanted for evaluation of syncope in 206 (66.0%), presyncope in 23 (7.4%), unexplained palpitations in 51 (16.3%), and cryptogenic stroke in 27 (8.7%) patients. ILR monitoring yielded a diagnosis that changed management strategy in 146 (46.8%) patients over a median of 12 (1‐42) months. Out of 163 (52.2%) patients with symptoms during the monitoring period, 100 (61.3%) had an arrhythmia. ILR was useful in ruling out an arrhythmic cause for symptoms in 63 (38.7%) patients. ILR results led to pacemaker implantation in 23 patients (7.4% overall and 11.2% of those with syncope) after median follow‐up of 3 months. A new diagnosis of atrial fibrillation was made in 38 (12.2%) patients, 11 of whom were initiated on oral anticoagulants. ILR results led to pacemaker implantation in 31 patients (9.9% overall and 19.0% of those with syncope) after median follow‐up of 3 months. A new diagnosis of atrial fibrillation was made in 38 (12.2%) patients, nine of whom were initiated on oral anticoagulants. Overall, ILR led to a change in management in 47% patients with a number needed to implant of 2.1 to change management.ConclusionILR monitoring is effective in achieving symptom‐rhythm correlation and results in changes in management in nearly half of implanted patients. Additional studies are needed to evaluate cost efficacy of ILR and the optimal monitoring duration.

Background: Right ventricular systolic dysfunction (RVD) often coexists with various cardiopulmonary diseases. However, the association between RVD and risk of sudden cardiac death (SCD) has not been well studied. This study examined the risk of SCD associated with RVD in patients with heterogeneous underlying cardiac diseases. Methods: The Mayo Clinic cardiac care unit database included 5463 consecutive patients with complete echocardiographic evaluation to assess right ventricular systolic function and RVD severity. Prospective surveillance follow-up was obtained for all patients. SCD was adjudicated when a malignant ventricular arrhythmia was documented as the primary rhythm leading to death. RESULTS: The prevalence of mild RVD and moderate-severe RVD was 14.9% and 17.1%, respectively. Patients with RVD were more likely to have a history of congestive heart failure, cardiac arrest, pulmonary disease, and lower baseline left ventricular ejection fraction compared with those with normal right ventricular systolic function. During a median follow-up of 14 months, the incidence of SCD was highest in patients with moderate-severe RVD (7.4% versus 4.4% in mild RVD versus 1.6% in normal right ventricular function; P <0.001). After adjustment for baseline characteristics, mild RVD (adjusted hazard ratio, 1.57; P =0.046) and moderate-severe RVD (adjusted hazard ratio, 1.91; P =0.006) were independently associated with an increased risk of SCD. Moderate-severe RVD remained an independent predictor of SCD for patients with left ventricular ejection fraction >35% without or with preexisting implantable cardioverter-defibrillator (adjusted hazard ratio, 4.12; P =0.003 and adjusted hazard ratio, 5.04; P <0.001, respectively). Conclusions: Presence of RVD in patients with a history of preexisting cardiac disease is an independent predictor of SCD irrespective of left ventricular ejection fraction.

IntroductionDofetilide is a class III antiarrhythmic prescribed to cardiovert persistent atrial fibrillation (AF) to sinus rhythm (SR).HypothesisTo determine the clinical predictors of cardioversion and readmission in persistent AF patients on dofetilide.MethodsWe analyzed 160 patients with persistent AF who were started on dofetilide and followed for 1 year. We examined age, sex, race, hypertension, diabetes, smoking, dyslipidemia, CAD, left ventricular ejection fraction (LVEF), creatinine, BMI and concomitant use of calcium channel blockers (CCB), β‐blockers in a multivariable logistic regression model. We also examined the same predictors in Cox regression model for AF‐related readmission within 1 year of follow‐up.Results13.5% individuals did not convert to SR on dofetilide. 55.6% converted on the first dose and 83.1% converted by the fourth dose. In multivariable logistic models, dyslipidemia (OR: 2.4, CI: 1.12‐5.16) and LVEF (OR: 3.83,CI: 1.37‐10.8) were associated with failure to convert with the first dose. Female sex and LVEF also were associated with increased risk of failure to convert at all. Concomitant use of CCB associated with decreased risk of failure to convert to SR. In Cox proportional model, female sex, age <63 years and CAD were associated with increased AF readmission within 1 year.ConclusionsDyslipidemia and LVEF <40% were associated with failure to cardiovert after first dose, and female sex and LVEF 40% were related to failure to convert at all on dofetilide in persistent AF patients. After 1‐year follow‐up, female sex, known CAD, and age <63 years were associated with increased AF readmissions.