Jian Ming Li

Comparison of automatic and patient-activated arrhythmia recordings by implantable loop recorders in the evaluation of syncope

The implantable loop recorder (ILR) has become an important tool for evaluating patients with recurrent syncope. Second generation ILRs have the ability to record events either automatically (auto activated) or by manual activation (patient activated). In an attempt to evaluate the relative utility of the auto-activation feature, this study stratified ILR events based on a grading system designed to classify detected arrhythmias in terms of the likelihood that they provide a diagnostic basis for syncope. Data from 50 patients (27 men, mean age 64 ± 22 years) who underwent ILR implantation for investigation of recurrent syncope were assessed. The arrhythmia syncope grading system used 5 levels, ranging from grade 0 (rhythm recorded during syncope) to grade IV (rhythm unlikely to provide a diagnostic basis for syncope). Thirty-six patients (72%) demonstrated ≥1 auto-activated or patient-activated recording during a follow-up of 14.3 ± 7.9 months. Of the total of 529 recordings, 223 (194 after auto activation [86.9%]) from 30 patients showed a rhythm abnormality. Auto activation was more effective for documenting arrhythmias that were recorded during syncope or those with highest probability of providing a syncope diagnosis (grade 0 or I arrhythmias: auto activated, 19 patients, patient activated, 3 patients). Times from ILR implantation to first grade 0 and grade I arrhythmias were 13.4 and 7.8 months, respectively. The ILR auto-activation feature proved effective in providing a high probability basis for syncope (196 arrhythmia recordings [87.1%] in 27 patients) and enhanced the diagnostic effectiveness of the device compared with patient activation alone (29 arrhythmia recordings [12.9%] in 6 patients).

Incidence of Appropriate Shock in Implantable Cardioverter- Defibrillator Patients With Improved Ejection Fraction

BACKGROUNDnHeart failure with recovered ejection fraction (EF) is a recently described clinical entity. There is insufficient information on the management of implantable-cardioverter defibrillator (ICD) patients with improved EF at generator replacement.nnnMETHODS AND RESULTSnWe examined the incidence of appropriate shocks in 91 consecutive patients with ICDs for primary prevention of sudden death who underwent generator replacement. Improved EF wasxa0defined as both EF >35% at generator replacement and increase in EF by ≥10% since original implantation. Patients were 70 ± 11 years old, and 76% had ischemic cardiomyopathy. At generator replacement, 25 patients (27%) had improved EF (0.49 ± 0.08 vs 0.31 ± 0.07 at baseline; P < .0001). Over 6.2 ± 2.2 years of follow-up after original implantation, 9 patients (36%) with improved EF versus 19xa0(29%) with unchanged EF had appropriate ICD shocks (Pxa0= .51). Incidence of appropriate ICD shocks was similar between the two groups before (Pxa0= .90) and after (Pxa0= .97) generator replacement. Of the 9xa0improved EF patients with appropriate shock, 4 had shocks before generator replacement, 2 had shocks before and after generator replacement, and 3 patients, who never had shocks before, had their first shock after generator replacement.nnnCONCLUSIONSnSome ICD patients whose EF improves to >35% at generator replacement remain at risk for appropriate ICD shocks.

Dose dependent effect of statins on postoperative atrial fibrillation after cardiac surgery among patients treated with beta blockers

BackgroundPrevious studies on the effects of Statins in preventing atrial fibrillation (AF) after cardiac surgery have shown conflicting results. Whether statins prevent AF in patients treated with postoperative beta blockers and whether the statin-effect is dose related are unknown.MethodsWe retrospectively studied 1936 consecutive patients who underwent coronary artery bypass graft (CABG) (n = 1493) or valve surgery (n = 443) at the Minneapolis Veterans Affairs Medical Center. All patients were in sinus rhythm before the surgery. Postoperative beta blockers were administered routinely (92% within 24 hours postoperatively).ResultsMean age was 66+10 years and 68% of the patients were taking Statins. Postoperative AF occurred in 588 (30%) patients and led to longer length of stay in the intensive care unit versus those without AF (5.1+7.6 days versus 2.5+2.3 days, p < 0.0001). Patients with a past history of AF had a 5 times higher risk of postoperative AF (odds ratio 5.1; 95% confidence interval 3.4 to 7.7; p < 0.0001). AF occurred in 31% of patients taking statins versus 29% of the others (p = 0.49). In multivariable analysis, statins were not associated with AF (odds ratio (OR) 0.93, 95% confidence interval (CI) 0.7 to 1.2; p = 0.59). However, in a subgroup analysis, the patients treated with Simvastatin >20 mg daily had a 36% reduction in the risk of postoperative AF (OR 0.64, 95% CI 0.43 to 0.6; p = 0.03) in comparison to those taking lower dosages.ConclusionAmong cardiac surgery patients treated with postoperative beta blockers Statin treatment reduces the incidence of postoperative AF when used at higher dosages

Atrial Fibrillation Associated with Hypokalemia Due to Primary Hyperaldosteronism (Conn's Syndrome)

Aldosterone is a major regulator of the body potassium stores through its role in potassium excretion by the kidney. However, it is unclear whether aldosterone affects transcellular distribution of potassium in atrial myocytes, and whether hypokalemia associated with primary hyperaldosteronism increases susceptibility to atrial fibrillation (AF). We report a case of a 58‐year‐old male with Conns syndrome in whom symptomatic AF was related to hypokalemia.

Discontinuation of Dofetilide From QT Prolongation and Ventricular Tachycardia in the Real World

OBJECTIVESnThe purpose of this study was to determine the incidence and correlates of QT prolongation or ventricular tachycardia (VT) resulting in discontinuation of dofetilide in a real-world setting.nnnBACKGROUNDnDofetilide is a class III antiarrhythmic agent approved for achieving and maintaining sinus rhythm in patients with symptomatic atrial fibrillation. Because of a risk of QT prolongation and VT, patients starting dofetilide need to be hospitalized for 3 days to closely monitor telemetry and electrocardiography. In large clinical trials,xa0<3% of patients had to discontinue dofetilide because of QT prolongation, but data from real-world experience are lacking.nnnMETHODSnWe examined 114 consecutive patients with atrial fibrillation who were hospitalized for starting dofetilide at the Minneapolis Veterans Affairs Health Care System from 2011 toxa02014.nnnRESULTSnThe mean age of the patients was 64 ± 8 years. Dofetilide was discontinued in 22 (19%) patients because of QT prolongation (17%) or VT (2%). A total of 32 (28%) patients were taking other QT-prolonging drugs. Of these, 10xa0(31%) had to discontinue dofetilide versus 12 (15%) of the 82 patients who were not taking any other QT-prolonging drugs (pxa0= 0.04). Patients who were taking concomitant QT-prolonging drugs were 1.9 times more likely to discontinue dofetilide (95% confidence interval: 1.1 to 3.4; pxa0= 0.04) compared with those who were not taking any other QT-prolonging drugs.nnnCONCLUSIONSnThe incidence of QT prolongation or VT that lead to discontinuation of dofetilide is remarkably higher in the real-world setting than in clinical trials. Concomitant use of other QT-prolonging drugs was associated with discontinuation of dofetilide.

Improvement of left ventricular diastolic function and left atrial reverse remodeling after catheter ablation of premature ventricular complexes

AimsCatheter ablation of premature ventricular complexes (PVC) improves left ventricular (LV) systolic performance in certain patients; however, the effect on diastolic function and left atrial (LA) remodeling is unclear. We assessed the effects of catheter ablation of PVCs on parameters of LV diastolic function and LA remodeling.MethodsForty-seven patients (age 65u2009±u200910xa0years, 46 men) who underwent catheter ablation for symptomatic PVCs were evaluated using two-dimensional echocardiography before and 6u2009±u20092xa0months after ablation. The measured diastolic indices included mitral inflow parameters (E wave, A wave, E/A ratio, and deceleration time (DT)), mitral lateral annulus early diastolic velocity (Ea), and E/Ea ratio. The LA volume was measured using modified biplane Simpsons method. We also compared the changes in the left atrial volumes and left atrial volume index (LAVI) after PVC ablation.ResultsAfter catheter ablation of PVCs, the mean LV ejection fraction (EF) increased significantly (49.9u2009±u200910.3 vs. 42.8u2009±u200911.8, pu2009<u20090.01). Significant improvement was also seen in A wave velocity (71.3u2009±u200917.1 vs. 59.5u2009±u200915.1xa0cm/s, pu2009=u20090.039), E/A ratio (1.42u2009±u20090.6 vs. 1.07u2009±u20090.5xa0ml, pu2009=u20090.034), Ea (8.9u2009±u20093.9 vs. 6.8u2009±u20092.9xa0cm/s, pu2009=u20090.04), and E/Ea ratio (15.4u2009±u20095.8 vs. 10.6u2009±u20093.4, pu2009=u20090.027), whereas mitral E and DT did not show significant change. LAVI decreased significantly after ablation (44.4u2009±u200914.8 vs. 36.7u2009±u200912.5, pu2009<u20090.001). Significant improvement in LAVI was also seen in patients with normal baseline LVEF (pu2009=u20090.04).ConclusionCatheter ablation of PVCs improved LV diastolic function and resulted in left atrial reverse remodeling.

Proximal Subclavian Artery Stenosis Diagnosis and Repair Documented by Both Myocardial Perfusion Imaging and Angiography

A 63-year-old man presented with a 3-month history of progressive angina relieved by rest. The chest pain worsened with exertion and radiated to his left arm. The use of his arms also exacerbated the pain. His medical history was significant for coronary artery disease, 4-vessel coronary artery bypass grafts (1997), mild hypertension, peripheral vascular disease, dyslipidemia, and type 2 diabetes mellitus. On admission, a 12-lead ECG and serial cardiac enzymes were negative for myocardial ischemia. An exercise thallium stress test demonstrated a large area of reversible ischemia in the anterior, septal, and …

Post-Extrasystolic Potentiation as a Predictor of Recovery of Left Ventricular Dysfunction After Radiofrequency Catheter Ablation

OBJECTIVESnThis study hypothesizes that post-extrasystolic potentiation reflects left ventricle contractile reserve and therefore may predict an improvement of premature ventricular contraction (PVC)-induced cardiomyopathy after PVC ablation.nnnBACKGROUNDnPost-extrasystolic potentiation is a physiologic phenomenon of blood pressure accentuation after a PVC beat.nnnMETHODSnWe performed a retrospective study of patients with a PVC burden ofxa0≥10% PVC/24 h and left ventricular ejection fraction (LVEF) ofxa0<50% who underwent successful ablation between January 1, 2009, to June 30, 2015. Subjects were classified as having reversible (a final LVEFxa0≥50%) or irreversible (final LVEFxa0<50%) LV dysfunction on a follow-up echocardiogram. A reference (control) group withxa0≥10% PVC but normal LV function was also identified.nnnRESULTSnSixty-one patients (age 68 ± 11 years, 98% male) were studied: 30 with preserved and 31 with reduced LVEF. During median follow-up of 9.4 months, the LVEF of 17 of 31 reduced EF patients improved (reversible) but 14 did not (irreversible). The post-PVC beat systolic blood pressure (SBP) (mmxa0Hg) increase ranged from 12.1 in control subjects (LVEF >50%) to 11.5 in reversible patients to 5 in irreversible patients. In multivariate analysis, the independent predictors of reversible LV function were post-PVC SBP rise (odds ratio [OR]: 4.61; 95% confidence interval [CI]: 1.45 to 15.83 per 5-mm Hg increase; pxa0< 0.001), post-PVC pulse pressure change (OR: 5.2; 95% CI: 2.3 to 18.6 per 5-mm Hg increase; pxa0< 0.001), and PVC QRS duration (OR: 2.78; 95% CI: 1.63 to 10.94 per 10-ms increase; pxa0< 0.001).nnnCONCLUSIONSnIn patients with LV dysfunction and frequent PVC, post-PVC SBP accentuation may be a marker forxa0subsequent recovery of LVEF after ablation in presumed PVC-induced cardiomyopathy.

Efficacy and benefits of catheter ablation of ventricular premature complexes in patients younger and older than 65 years of age.

OBJECTIVESnCatheter ablation of ventricular premature complexes (VPC) improves clinical status and systolic performance of the left ventricle (LV) in a certain subset of patients; however, whether or not VPC ablation is equally effective in younger (<=65 years) and older (>65 years) patients remains unclear. We aimed to assess the clinical benefits of catheter ablation of VPCs in elderly patients.nnnSTUDY DESIGNnFifty-one consecutive patients (66±10 years, 49 male) who underwent catheter ablation for symptomatic VPCs were included into the study. Twenty-seven patients were aged >65 years and 24 patients <=65 years. Frequency of VPCs per total heart beats by 24-hour Holter monitoring, LV ejection fraction (LVEF) and end-systolic diameters (LVEDD) were evaluated before and 6±3 months after ablation.nnnRESULTSnThe pre-ablation 24-hour VPC burden and VPC number were significantly higher in patients >65 years compared to those <=65 years (31±15.3 vs. 21.9±12.6, p=0.04 and 34493±21226 vs. 23554±13792, p=0.026, respectively). At the follow-up after catheter ablation, the mean VPC burden had decreased to 9.1±10.3% (p<0.001) in patients >65 years and to 3.8±7.1 (p<0.001) in patients <=65 years. Mean LVEF showed a significant increase in both groups after ablation (43.4±10.4 vs. 51.5±8.2, p=0.005 for age >65 years and 40.8±13.2 vs. 49.5±11.8, p=0.003 for age <=65 years). The improvement in LVEF was accompanied by a significant decrease in LVEDD (p=0.032 for age >65 years and p=0.047 for <=65 years).nnnCONCLUSIONnCatheter ablation is effective for treatment of frequent VPCs in all age groups.

Electrophysiological characteristics and radiofrequency ablation of sustained monomorphic ventricular tachycardia in adult patients with isolated ventricular noncompaction

AbstractsPurposeThis study examined electrophysiological characteristics and outcomes of patients with sustained ventricular tachycardia (VT) in the setting of isolated ventricular noncompaction (IVNC).BackgroundIn patients with IVNC, VT has been associated with sudden cardiac death. However, the electrophysiological characteristics and optimal management of these VTs are only incompletely understood.MethodsThis retrospective cohort study assessed arrhythmia characteristics and outcomes in IVNC patients with sustained monomorphic VTs. Data were obtained from five academic centers covering the time period from January 1, 2006, to December 31, 2016, with a median follow-up of 40xa0months.ResultsEighteen consecutive IVNC patients with sustained VTs (12 males [66%], mean age of 44.4u2009±u200916.9xa0years) were enrolled. Seven (39%) patients underwent VT ablation (five males, mean age of 43.3u2009±u200915.5xa0years) and nine (50%) patients received ICD therapy. Six of 18 patients (33%) died during a median follow-up of 40xa0months. Of these, three had ICDs, two had undergone VT ablation, and one had received only antiarrhythmic drugs. Among the seven patients with prior VT ablation, five VTs in the RV (three RVOT and one tricuspid annulus) and two LV VTs (one anterolateral papillary muscle and one inferolateral wall) were localized by 3-D mapping and successfully ablated. In six of seven ablation cases (85.7%), the VTs were distant from the noncompaction zone. VTs appeared to be focal in 57% (4/7) and macro-reentry in 43% (3/7) of patients based on 3-D mapping and entrainment studies. The success rate of VT ablation was 85.7% with one VT recurrence and two deaths during the mean follow-up of 54 (28–115)xa0months.ConclusionsIVNC Patients with sustained VTs appear to have a poor prognosis despite receiving ICD or apparently successful VT ablation therapy. Further, most VTs appear to arise remote from the noncompaction zone. Whether these VTs were “idiopathic” or related to IVNC was uncertain.