Rate of Change of Initial Intrinsicoid Deflection Predicts Endocardial Versus Epicardial Ventricular Tachycardia.

BACKGROUND: Assessment of origin of ventricular tachycardias (VTs) arising from epicardial vs endocardial sites are largely challenged by the available criteria and etiology of cardiomyopathy. Current electrocardiographic (ECG) criteria based on 12-lead ECG have varying sensitivity and specificity based on site of origin and etiology of cardiomyopathy. OBJECTIVES: This study sought to test the hypothesis that epicardial VT has a slower initial rate of depolarization than endocardial VT. METHODS: We developed a method that takes advantage of the fact that electrical conduction is faster through the cardiac conduction system than the myocardium, and that the conduction system is primarily an endocardial structure. The technique calculated the rate of change in the initial VT depolarization from a signal-averaged 12-lead ECG. We hypothesized that the rate of change of depolarization in endocardial VT would be faster than epicardial. We assessed by applying this technique among 26 patients with VT in nonischemic cardiomyopathy patients. RESULTS: When comparing patients with VTs ablated using epicardial and endocardial approaches, the rate of change of depolarization was found to be significantly slower in epicardial (6.3 ± 3.1 mV/s vs 11.4 ± 3.7 mV/s; P < 0.05). Statistical significance was found when averaging all 12 ECG leads and the limb leads, but not the precordial leads. Follow up analysis by calculation of a receiver-operating characteristic curve demonstrated that this analysis provides a strong prediction if a VT is epicardial in origin (AUC range 0.72-0.88). Slower rate of change of depolarization had high sensitivity and specificity for prediction of epicardial VT. CONCLUSIONS: This study demonstrates that depolarization rate analysis is a potential technique to predict if a VT is epicardial in nature.

Perioperative changes in left ventricular systolic function following surgical revascularization.

BACKGROUND: Nearly 1/3rd of patients undergoing coronary artery bypass graft surgery (CABG) have left ventricular systolic dysfunction. However, the extent, direction and implications of perioperative changes in left ventricular ejection fraction (LVEF) have not been well characterized in these patients. METHODS: We studied the changes in LVEF among 549 patients with left ventricular systolic dysfunction (LVEF <50%) who underwent CABG as part of the Surgical Treatment for Ischemic Heart Failure (STICH) trial. Patients had pre- and post-CABG (4 month) LVEF assessments using identical cardiac imaging modality, interpreted at a core laboratory. An absolute change of >10% in LVEF was considered clinically significant. RESULTS: Of the 549 patients (mean age 61.4±9.55 years, and 72 [13.1%] women), 145 (26.4%) had a >10% improvement in LVEF, 369 (67.2%) had no change and 35 (6.4%) had >10% worsening of LVEF following CABG. Patients with lower preoperative LVEF were more likely to experience an improvement after CABG (odds ratio 1.36; 95% CI 1.21-1.53; per 5% lower preoperative LVEF; p <0.001). Notably, incidence of postoperative improvement in LVEF was not influenced by presence, nor absence, of myocardial viability (25.5% vs. 28.3% respectively, p = 0.67). After adjusting for age, sex, baseline LVEF, and NYHA Class, a >10% improvement in LVEF after CABG was associated with a 57% lower risk of all-cause mortality (HR: 0.43, 95% CI: 0.26-0.71). CONCLUSIONS: Among patients with ischemic cardiomyopathy undergoing CABG, 26.4% had >10% improvement in LVEF. An improvement in LVEF was more likely in patients with lower preoperative LVEF and was associated with improved long-term survival.

Predictive Score for Identifying Survival and Recurrence Risk Profiles in Patients Undergoing Ventricular Tachycardia Ablation: The I-VT Score.

BACKGROUND: Several distinct risk factors for arrhythmia recurrence and mortality following ventricular tachycardia (VT) ablation have been described. The effect of concurrent risk factors has not been assessed so far; thus, it is not yet possible to estimate these risks for a patient with several comorbidities. The aim of the study was to identify specific risk groups for mortality and VT recurrence using the Survival Tree (ST) analysis method. METHODS: In 1251 patients 16 demographic, clinical and procedure-related variables were evaluated as potential prognostic factors using ST analysis using a recursive partitioning algorithm that searches for relationships among variables. Survival time and time to VT recurrence in groups derived from ST analysis were compared by a log-rank test. A random forest analysis was then run to extract a variable importance index and internally validate the ST models. RESULTS: Left ventricular ejection fraction, implantable cardioverter defibrillator/cardiac resynchronization device, previous ablation were, in hierarchical order, identified by ST analysis as best predictors of VT recurrence, while left ventricular ejection fraction, previous ablation, Electrical storm were identified as best predictors of mortality. Three groups with significantly different survival rates were identified. Among the high-risk group, 65.0% patients were survived and 52.1% patients were free from VT recurrence; within the medium- and low-risk groups, 84.0% and 97.2% patients survived, 72.4% and 88.4% were free from VT recurrence, respectively. CONCLUSIONS: Our study is the first to derive and validate a decisional model that provides estimates of VT recurrence and mortality with an effective classification tree. Preprocedure risk stratification could help optimize periprocedural and postprocedural care.

Successful ventricular tachycardia ablation in patients with electrical storm reduces recurrences and improves survival.

OBJECTIVE: The purpose of this study was to evaluate the characteristics and outcome of patients undergoing ablation after electrical storm (ES). METHODS: Clinical and procedural characteristics, ventricular tachycardia (VT) recurrence, and mortality rates from 1940 patients undergoing VT ablation were compared between patients with and without ES. RESULTS: The group of 677 patients with ES (34.9%) were older, were more frequently men, and had a lower ejection fraction, more advanced heart failure, and a higher prevalence of cardiovascular comorbidities as compared with those without ES (86.1% patients with ES had ≥2 comorbidities vs 71.4%; P < .001). Patients with ES had more inducible VTs (2.5 ± 1.8 vs 1.9 ± 1.9; P < .001), required longer procedures (296.1 ± 119.1 minutes vs 265.7 ± 110.3 minutes; P < .001), and had a higher in-hospital mortality (42 deaths [6.2%] vs 18 deaths [1.4%]; P < .001). At 1-year follow-up, patients with ES experienced a higher risk of VT recurrence and mortality (32.1% vs 22.6% and 20.1% vs 8.5%; long-rank, P < .001 for both). Among patients with ES, those without any inducible VT after ablation had a higher survival rate (86.3%) than did those with nonclinical VTs only (72.9%), those with clinical VTs inducible at programmed electrical stimulation (51.2%), and not-tested patients (65.0%) (long-rank, P < .001 for all). In multivariate analysis, ES remained an independent predictor of in-hospital mortality, VT recurrence, and 1-year mortality (P < .001). CONCLUSION: Patients with ES have a high risk of VT recurrence and mortality. Patient and procedure characteristics are consistent with advanced cardiac disease and longer and more complex procedures. In patients with ES, acute procedural success is associated with a significant reduction in VT recurrence and improved 1-year survival.

Early Mortality After Catheter Ablation of Ventricular Tachycardia in Patients With Structural Heart Disease.

BACKGROUND: In patients referred for radiofrequency catheter ablation (RFCA) of ventricular tachycardia (VT) in the setting of structural heart disease, early post-procedural mortality (EM) has not been previously investigated. OBJECTIVES: The purpose of this study was to evaluate EM after catheter ablation of scar-related VT. METHODS: Associations between clinical and procedural variables and EM (within 31 days of the procedure) were tested in patients with structural heart disease undergoing RFCA of VT at 12 international centers. RESULTS: Of 2,061 patients (mean age 62 ± 13 years; left ventricular ejection fraction [LVEF] 34 ± 13%; 53% ischemic etiology), EM occurred in 100 (5%; 95% confidence interval [CI]: 4% to 6%). A total of 54 (3%) patients died before hospital discharge (median 9 days after the procedure; 25% for refractory VT), including 12 (0.6%) after a major procedure-related complication. In multivariable analysis, the following factors were found to be significantly associated with EM: LVEF (odds ratio [OR] per percent decrease: 1.12; 95% CI: 1.05 to 1.20; p < 0.001), chronic kidney disease (OR: 2.73; 95% CI: 1.10 to 6.80; p = 0.030), presentation with VT storm (OR: 3.61; 95% CI: 1.37 to 9.48; p = 0.009), and presence of unmappable VTs (OR: 5.69; 95% CI: 1.37 to 23.69; p = 0.017). Recurrent VT was also associated with an increased risk of subsequent death (hazard ratio: 7.19; 95% CI: 5.57 to 9.28; p < 0.001) and EM (hazard ratio: 11.45; 95% CI: 7.47 to 17.59; p < 0.001). CONCLUSIONS: In a contemporary cohort of patients with scar-related VT undergoing RFCA, EM occurred in 5% of cases. Clinical and procedural variables indicating poorer clinical status (low LVEF, chronic kidney disease, VT storm, and unmappable VTs) and post-procedural VT recurrence may predict EM. Identification of such features may prompt early consideration for hemodynamic support or other care to help mitigate later potential complications.

Hemodynamic Support in Ventricular Tachycardia Ablation: An International VT Ablation Center Collaborative Group Study.

OBJECTIVES: This study sought to evaluate the clinical outcomes of patients receiving hemodynamic support (HS) during ventricular tacchycardia (VT) ablation. BACKGROUND: There are limited real-world data evaluating its effect of HS in ablation outcomes. METHODS: An analysis of 1,655 patients from the International VT Ablation Center Collaborative group was performed. A total of 105 patients received HS with percutaneous ventricular assist device. RESULTS: Patients in the HS group had lower left ventricular ejection fraction (LVEF), higher New York Heart Association (NYHA) functional class, and more implantable cardioverter-defibrillator (ICD) shocks, VT storm, and antiarrhythmic drug use (all p < 0.05). The HS group also required significantly longer fluoroscopy, procedure, and total lesion time. Acute procedural success (71.8% vs. 73.7%; p = 0.04) was significantly lower and complications (12.5% vs. 6.5%; p = 0.03) and 1-year mortality (34.7% vs. 9.3%; p < 0.001) were significantly higher in the HS group. Multivariate Cox regression analysis demonstrated HS as an independent predictor of mortality (hazard ratio: 5.01; 95% confidence interval: 3.44 to 7.20; p < 0.001). There was no significant difference in VT recurrence between groups. In a subgroup analysis including LVEF ≤20% and NYHA functional class III to IV patients, acute procedural success (74.0% vs. 70.5%; p = 0.8), complications (15.6% vs. 7.8%; p = 0.2), VT recurrence (30.2% vs. 38.1%; p = 0.44), and 1-year mortality (40.0% vs. 28.8%; p = 0.2) were no different between the HS and no-HS groups. CONCLUSIONS: Patients requiring HS were sicker with multiple comorbidities and, as expected, had a significantly higher 1-year mortality than did those patients in the no-HS group. In patients with LVEF ≤20% and NYHA functional class III to IV, there was also no significant difference in clinical outcomes when compared with no HS. Further studies are needed to systematically evaluate patients undergoing VT ablation receiving HS.

Carbamazepine-induced atrioventricular block in an elderly woman.

An 88-year-old woman was admitted to the emergency department after experiencing syncope while in a sitting position. Electrocardiogram showed advanced degree heart block. She has been on low-dose carbamazepine (200 mg/day) for the last year for trigeminal neuralgia (TN). After discontinuation of carbamazepine, the patient returned to normal sinus rhythm.

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

OBJECTIVES: Catheter 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. STUDY DESIGN: Fifty-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. RESULTS: The 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). CONCLUSION: Catheter ablation is effective for treatment of frequent VPCs in all age groups.

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

AIMS: Catheter 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. METHODS: Forty-seven patients (age 65 ± 10 years, 46 men) who underwent catheter ablation for symptomatic PVCs were evaluated using two-dimensional echocardiography before and 6 ± 2 months 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 Simpson's method. We also compared the changes in the left atrial volumes and left atrial volume index (LAVI) after PVC ablation. RESULTS: After catheter ablation of PVCs, the mean LV ejection fraction (EF) increased significantly (49.9 ± 10.3 vs. 42.8 ± 11.8, p < 0.01). Significant improvement was also seen in A wave velocity (71.3 ± 17.1 vs. 59.5 ± 15.1 cm/s, p = 0.039), E/A ratio (1.42 ± 0.6 vs. 1.07 ± 0.5 ml, p = 0.034), Ea (8.9 ± 3.9 vs. 6.8 ± 2.9 cm/s, p = 0.04), and E/Ea ratio (15.4 ± 5.8 vs. 10.6 ± 3.4, p = 0.027), whereas mitral E and DT did not show significant change. LAVI decreased significantly after ablation (44.4 ± 14.8 vs. 36.7 ± 12.5, p < 0.001). Significant improvement in LAVI was also seen in patients with normal baseline LVEF (p = 0.04). CONCLUSION: Catheter ablation of PVCs improved LV diastolic function and resulted in left atrial reverse remodeling.

Risk of acute kidney injury in patients who undergo coronary angiography and cardiac surgery in close succession.

AIMS: Cardiac surgery and coronary angiography are both associated with risk of acute kidney injury (AKI). We hypothesized that the risk of post-operative AKI increases when coronary angiogram and cardiac surgery are performed in close succession, without sufficient time for recovery from the adverse effects of intravenous contrast. METHODS AND RESULTS: We included 2133 consecutive patients who underwent cardiac surgery at the Minneapolis Veterans Administration Medical Center from 2004 to 2010. Acute kidney injury was defined by the AKI network and the risk, injury, failure, loss, end-stage (RIFLE) criteria. Patients were 66 ± 10 years old. Mean pre-operative creatinine and estimated glomerular filtration rate were 1.1 ± 0.4 mg/dL and 75 ± 22 mL/min/1.73 m(2), respectively. Cardiac surgery was performed 14 days (range 0-235) after coronary angiography. Acute kidney injury occurred in 680 (32%) patients per AKI network, 390 (18%) patients per RIFLE risk, and 111 (5%) patients per RIFLE injury criteria. Age, body mass index, diabetes mellitus, New York Heart Association class III/IV, cardiopulmonary bypass time, and impaired pre-operative renal function were independent predictors of AKI. However, time between coronary angiogram and cardiac surgery was not a predictor (P = 0.41). AKI occurred in 35% of 433 patients operated within 3 days of coronary angiogram vs. 31% of 1700 patients operated after 3 days (P = 0.17). Results were the same in patients with impaired pre-operative renal function and those with contrast-induced nephropathy. CONCLUSION: Risk of AKI after cardiac surgery is not influenced by the time between coronary angiogram and cardiac surgery. These results do not support the notion of delaying cardiac surgery for the sole purpose of renal recovery after coronary angiogram.

An unusual cause of asystole during a routine pacemaker generator change.

A 74-year-old pacemaker-dependent male patient, who underwent a pacemaker generator change due to elective replacement indicator, had a 4-second pause during interrogation of the new pacemaker generator out of the device pocket due to a specific feature that was programmed on called"enhanced transtelephonic monitoring."

Assessment of percutaneous coronary intervention on regional and global left ventricular function in patients with chronic total occlusions.

BACKGROUND: The improvement of regional and global ventricular function following percutaneous coronary intervention (PCI) with reperfusion of the artery supplying the infarct area in acute myocardial infarction is well-described. However, little is known of the potential effects of late recanalization of chronic coronary artery occlusion on left ventricular function. OBJECTIVE: To determine whether PCI improves regional and global left ventricular function in patients with chronic coronary artery occlusions. PATIENTS AND METHODS: Thirty-five patients having at least one coronary artery occluded for six weeks or longer were included in the present prospective study. Exercise thallium-201 myocardial perfusion scintigraphy, multiple-gated acquisition ventriculography and two-dimensional echocardiography were performed in 19 patients (16 men; mean age of 58+/-5 years) who underwent a successful PCI to assess both regional and global left ventricular function before and six weeks following the procedure. RESULTS: The mean ejection fractions before and after reperfusion were 51+/-7% and 58+/-6% using Simpson's method (P<0.001) by echocardiography, and 45+/-1% and 53+/-1% (P=0.01) by multiple-gated acquisition ventriculography, respectively. The echocardiographic wall motion score was 24+/-9 before and 15+/-6 after PCI (P<0.001). The exercise perfusion score (21+/-1 and 14+/-1 [P=0.01]), rest perfusion score (15+/-1 and 12+/-1 [P=0.02]) and reinjection perfusion score (14+/-1 and 11.1+/-1 [P=0.07]) also improved after PCI. The presence of angina was strongly associated with an improvement in left ventricular function and wall motion score (P<0.01). CONCLUSIONS: PCI significantly improved the regional and global left ventricular function in patients with chronic total coronary occlusion. This procedure may provide symptom benefits in selected patients.