Interventricular septal thickness on cardiac computed tomography as a novel risk factor for conduction disturbances in patients undergoing transcatheter aortic valve replacement.

AIMS: We examined whether thickness of the basal muscular interventricular septum (IVS), as measured by pre-procedural computed tomography (CT), could be used to identify the risk of conduction disturbances following transcatheter aortic valve replacement (TAVR). The IVS is a pivotal region of the electrical conduction system of the heart where the atrioventricular conduction axis is located. METHODS AND RESULTS: Included were 78 patients with severe aortic stenosis who underwent CT imaging prior to TAVR. The thickness of muscular IVS was measured in the coronal view, in systolic phases, at 1, 2, 5, and 10 mm below the membranous septum (MS). The primary endpoint was a composite of conduction disturbance following TAVR. Conduction disturbances occurred in 24 out of 78 patients (30.8%). Those with conduction disturbances were significantly more likely to have a thinner IVS than those without conduction disturbances at every measured IVS level (2.98 ± 0.52 mm vs. 3.38 ± 0.52 mm, 4.10 ± 1.02 mm vs. 4.65 ± 0.78 mm, 6.11 ± 1.12 mm vs. 6.88 ± 1.03 mm, and 9.72 ± 1.95 mm vs. 10.70 ± 1.55 mm for 1, 2, 5 and 10 mm below MS, respectively, P < 0.05 for all). Multivariable logistic regression analysis showed that pre-procedural IVS thickness (<4 mm at 2 mm below the MS) was a significant independent predictor of post-procedural conduction disturbance (adjOR 7.387, 95% CI: 2.003-27.244, P = 0.003). CONCLUSION: Pre-procedural CT assessment of basal IVS thickness is a novel predictive marker for the risk of conduction disturbances following TAVR. The IVS thickness potentially acts as an anatomical barrier protecting the underlying conduction system from mechanical compression during TAVR.

Safety of High-Dose Dabigatran in Elderly and Younger Patients with a Low Bleeding Risk: A Prospective Observational Study.

INTRODUCTION: In patients with atrial fibrillation (AF) at risk for stroke, dabigatran 150 mg twice a day (DE150) is superior to warfarin for stroke prevention. However, there is paucity of data with respect to bleeding risk at this dose in elderly patients (≥75 years). We aimed to evaluate the safety of DE150 in comparison to warfarin in a real-world population with AF and low bleeding risk (HAS-BLED score ≤2). METHODS: In this prospective observational study, 754 consecutive patients with AF and HAS-BLED score ≤2 were included. We compared outcome of elderly patients (age ≥75 tears) to younger patients (age <75 years). The primary end point was the combined incidence of all-cause mortality, stroke, systemic emboli, and major bleeding event during a mean follow-up of 1 year. RESULTS: There were 230 (30%) elderly patients, 151 patients were treated with warfarin, and 79 were treated with DE150. Fifty-two patients experienced the primary endpoint during the 1-year follow-up. Among the elderly, at 1-year of follow-up, the cumulative event rate of the combined endpoint in the DE150 and warfarin was 8.9 and 15.9% respectively (p = 0.14). After adjustment for age and gender, patients who were treated with DE150 had a nonsignificant difference in the risk for the combined end point as patients treated with warfarin both among the elderly and among the younger population (HR 0.58, 95% C.I = 0.25-1.39 and HR = 1.12, 95% C.I 0.62-2.00, respectively [p for age-group-by-treatment interaction = 0.83). CONCLUSIONS: Our results suggest that Dabigatran 150 mg twice a day can be safely used among elderly AF patients with low bleeding risk.

Predicting the risk of late futile outcome after transcatheter aortic valve implantation.

BACKGROUND: Transcatheter aortic valve implantation (TAVI) for aortic stenosis (AS) risk assessment is still developing and mostly concerned with mortality in the periprocedural period. We therefore sought to develop and then validate a score to predict 1-year adverse outcome. METHODS: Patients that underwent TAVI for severe AS in the Israeli registry. Patients with unsuccessful/suboptimal implantation were excluded. The cohort was split to derivation/validation cohorts by a ratio of 70:30. The outcome was defined as 1-year composite of mortality, stroke, and no improvement in NYHA class (vs. baseline). Logistic regression was used to fit the prediction model. RESULTS: Out of 2,440 patients meeting inclusion criteria, 276 were excluded, leaving 2,160 patients for both cohorts. At 1 year, 299 (14%) patients experienced the adverse ("futile") outcome. The derived prediction model included mean aortic valve (AV) gradient, previous pacemaker, previous oncological disease, need for diuretics, baseline NYHA class, hemoglobin and creatinine levels, and nonfemoral access site. The model's area under the curve (AUC) was 0.69 in the derivation and 0.70 in the validation cohort. Performance of other scores in the validation cohort were lower (0.60 for STS, 0.55 for Euroscore2, 0.56 for TVT score, and 0.53 for TAVI2-score, p = .03). Based on three risk tiers, patients had a low risk (20/306, 7% futility), a medium risk (50/304, 17%), and high risk (18/37, 49%) for futility. CONCLUSIONS: The TAVI futility risk model can be used to provide further insight regarding prediction measures and/or patients' outcomes outside of the periprocedural period (NCT02023060).

Liver steatosis is a major predictor of poor outcomes in chronic hepatitis C patients with sustained virological response.

Sustained virological response (SVR) results in reduced incidence of hepatocellular carcinoma (HCC) and mortality among chronic hepatitis C (CHC) patients with advanced fibrosis. Since both advanced fibrosis and liver steatosis (LS) may coexist in CHC patients, we evaluated their individual effects on a composite outcome of all-cause mortality and HCC in CHC patients with SVR following direct-acting antivirals (DAA) treatment. We retrospectively evaluated inception cohort of 515 CHC patients who achieved SVR following treatment with DAA, with a mean follow-up of 24 months. Baseline liver fibrosis was assessed by transient elastography, and LS was validated by at least three independent ultrasonographic examinations. 211 of 515 patients (41%) had baseline LS. Patients with LS had a higher cumulative rate of all-cause mortality and HCC at 2 years of follow-up compared to patients without LS (15.75% and 2.79%, respectively, P < 0.001), although they did not have increased incidence of advanced fibrosis or cirrhosis. Consistently, multivariate analysis showed that LS was associated with a significant 7.5-fold increased risk of all-cause mortality and HCC (HR 7.51, 95% C.I 3.61-13.36, P < 0.001) even upon adjustment to components of the metabolic syndrome, whereas advanced fibrosis showed only a trend towards statistical significance (HR 2.32, 95% C.I 0.97-6.59, P = 0.06). In conclusion, LS is a major predictor of all-cause mortality and HCC in patients who achieved SVR following DAA treatment regardless of fibrosis stage. These patients should be rigorously screened for HCC.

Risk of death without appropriate defibrillator shock in patients with advanced renal dysfunction.

AIMS: Heart failure patients with advanced chronic kidney disease (CKD) may experience an increased rate of non-arrhythmic mortality due to associated comorbidities. We aimed to evaluate the risk of mortality without appropriate implantable cardioverter-defibrillator (ICD) shocks in this high-risk population. METHODS AND RESULTS: The study population comprised 3542 patients who received an ICD, were enrolled, and prospectively followed-up in the Israeli ICD registry. Study patients were categorized into two groups: those with advanced CKD [defined by a glomerular filtration rate of <30 mL/min/1.73 m2 or being on dialysis at time of implantation (n = 197)], and those without advanced CKD (n = 3344). The primary endpoint was the risk of death without receiving appropriate ICD shock. Kaplan-Meier survival analysis showed that at 5 years of follow-up the rates of death without prior ICD shock were significantly higher in the advanced kidney disease group (46%) compared with the non-advanced CKD group (19%; log-rank P-value <0.001). Consistently, multivariate analysis showed that the risk of death without receiving appropriate ICD shock therapy at 5 years was 2.5-fold (P < 0.001) higher among advanced CKD patients. In contrast, the rate of appropriate ICD shock therapy at 5 years among advanced CKD patients was only 9%, with a very high mortality rate (63%) within 3.5 years subsequent to shock therapy. CONCLUSION: Nearly one-half of ICD with advanced CKD die within 5 years without receiving an appropriate ICD shock. These findings stress the importance of appropriate patient selection for primary ICD implantation in this high-risk population.

Long-term Outcomes of Contemporary Coronary Revascularization by Percutaneous Coronary Intervention or Coronary Artery Bypass Grafting in Young Adults.

BACKGROUND: Current guidelines for choosing between revascularization modalities may not be appropriate for young patients. OBJECTIVES: To compare outcomes and guide treatment options for patients < 40 years of age, who underwent percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) between 2008 and 2018. METHODS: Outcomes were compared for 183 consecutive patients aged < 40 years who underwent PCI or CABG between 2008 and 2018, Outcomes were compared as time to first event and as cumulative events for non-fatal outcomes. RESULTS: Mean patient age was 36.3 years and 96% were male. Risk factors were similar for both groups. Drug eluting stents were implemented in 71% of PCI patients and total arterial revascularization in 74% of CABG patients. During a median follow-up of 6.5 years, 16 patients (8.6%) died. First cardiovascular events occurred in 35 (38.8%) of the PCI group vs. 29 (31.1%) of the CABG group (log rank P = 0.022), repeat events occurred in 96 vs. 51 (P < 0.01), respectively. After multivariate adjustment, CABG was associated with a significantly reduced risk for first adverse event (hazard ratio [HR] 0.305, P < 0.01) caused by a reduction in repeat revascularization. CABG was also associated with a reduction in overall repeat events (HR 0.293, P < 0.01). There was no difference in overall mortality between CABG and PCI. CONCLUSIONS: Young patients with coronary disease treated by CABG showed a reduction in the risk for non-fatal cardiac events. Mortality was similar with CABG and PCI.

Study of the wearable cardioverter defibrillator in advanced heart-failure patients (SWIFT).

INTRODUCTION: The wearable cardioverter defibrillator (WCD) may allow stabilization until reassessment for an implantable cardioverter defibrillator (ICD) among high-risk heart failure (HF) patients. However, there are limited data on the WCD benefit in the acute decompensated HF setting. METHODS AND RESULTS: The Study of the Wearable Cardioverter Defibrillator in Advanced Heart Failure Patients (SWIFT) was a prospective clinical trial carried out at two medical centers. Patients hospitalized with advanced HF symptoms and reduced left ventricular ejection function (LVEF) were enrolled and prescribed a WCD prior to discharge for a total of 3 months. Outcome measures included arrhythmic events, WCD discharge, and death. Study patients (n = 75, mean age 51 ± 14 years, 31% women) had a mean LVEF of 21.5 ± 10.4%. Non-ischemic cardiomyopathy was present in 66% of patients. The median WCD wearing time was 59 (interquartile range 17-97) days, and 80% of patients wore the device >50% of daily hours. WCD interrogations showed a total of 8 arrhythmic events in 5 patients, including 3 nonsustained or self-terminating ventricular tachycardia (VT) events, and one polymorphic VT successfully terminated by the WCD. None of the patients died while wearing the device and no inappropriate device therapies occurred. Upon termination of treatment with the WCD, 21 patients (28%) received an ICD. At 3 years, the cumulative death rate was 20% in the ischemic and 21% in non-ischemic cardiomyopathy patients. CONCLUSION: A management strategy incorporating the WCD can be safely used to bridge the decision regarding the need for ICD implantation in high-risk patients with advanced HF.

Admission blood glucose and 10-year mortality among patients with or without pre-existing diabetes mellitus hospitalized with heart failure.

BACKGROUND: High admission blood glucose (ABG) level has been associated with a poor short-term outcome among non-diabetic patients with heart failure (HF). We aimed to investigate the association between ABG levels and long-term (10 years) mortality in patients with or without pre-existing diabetes mellitus (DM) admitted with HF. METHODS: We analyzed data on 1811 patients with DM and 2182 patients without pre-existing DM who were hospitalized with HF during a prospective national survey. The relationship between ABG and 10-year mortality was assessed using the Cox proportional hazard model adjusting for multiple variables. ABG was analyzed both as a categorical (<110, 110-140, 140-200, and >200 mg/dL) and as a continuous variable. RESULTS: At 10 years of follow-up the cumulative probability of mortality was 85 and 78% among patients with DM and patients with no pre-existing DM (p < 0.001), respectively. Among patients with no pre-existing DM, glucose levels of 110-140, 140-200 and ≥200 mg/dL were associated with 9% (p = 0.140), 16% (p = 0.031) and 53% (p < 0.001) increased mortality risk compared to ABG < 110 mg/dL. Each 18-mg/dL (1-mmol/L) increase in glucose level was associated with a 5% increased risk of mortality (p < 0.001) among patients with no-pre-existing DM. In contrast, among patients with DM, only those with glucose levels >200 mg/dL had an increased mortality risk (>200 mg/dL versus <110 mg/dL; HR = 1.20, p = 0.032). CONCLUSION: Among hospitalized HF patients with no pre-existing DM there is a linear relationship between ABG level and long-term mortality, whereas among patients with DM only ABG level >200 mg/dL is associated with increased mortality risk.

Prognostic significance of aortic valve gradient in patients with severe aortic stenosis undergoing transcatheter aortic valve replacement.

OBJECTIVE: To evaluate the effect of baseline aortic valve gradient (AVG) both as a continuous and a categorical variable on mortality in patients undergoing transcatheter aortic valve replacement (TAVR), focusing on the high-gradient severe aortic stenosis (AS) patients. BACKGROUND: Identifying new predictors of mortality in the TAVR population can help refine risk stratification and improve the patient selection process for this procedure. So far, AVG has mainly been studied as a categorical variable and there is a paucity of data on its prognostic value as a continuous variable, especially in patients with high AVG AS, who constitute the majority of patients referred for TAVR. METHODS: We analyzed data on 1,224 consecutive symptomatic severe AS patients, who underwent TAVR at 3 centers. The relation between pre-TAVR AVG and mortality was evaluated among all patients and in patients with high AVGs (mean AVG ≥40 mm Hg) using the Cox proportional hazard model adjusting for multiple variables. RESULTS: During a mean follow-up of 1.8 years, baseline AVG was inversely associated with mortality in the entire cohort and in patients with high AVG AS. By multivariable analysis, patients with mean AVG 40-60 mm Hg and >60 mm Hg had a respective 38% (P = 0.010) and 61% (P < 0.001) reduction in mortality compared to patients with mean AVG <40 mm Hg. Every 10 mm Hg increase in mean AVG was associated with 20% reduction in mortality (P < 0.001). Analyses among patients with high (mean AVG >40 mm Hg) and very high AVG AS (mean AVG >60 mm Hg) yielded similar results (HR = 0.88, P = 0.031, and HR = 0.80, P = 0.019, per 10 mm Hg increase in AVG, respectively). Using peak AVGs and an analysis restricted to patients without reduced ejection fraction yielded consistent results. CONCLUSIONS: Baseline AVGs show an inverse association with mortality post-TAVR. These results were consistent also in patients with high-gradient AS, suggesting that AVG can be used to identify patients most likely to benefit from TAVR.

Contemporary rates and outcomes of single- vs. dual-coil implantable cardioverter defibrillator lead implantation: data from the Israeli ICD Registry.

AIMS: Dual-coil leads were traditionally considered standard of care due to lower defibrillation thresholds (DFT). Higher complication rates during extraction with parallel progression in implantable cardioverter defibrillator (ICD) technology raised questions on dual coil necessity. Prior substudies found no significant outcome difference between dual and single coils, although using higher rates of DFT testing then currently practiced. We evaluated the temporal trends in implantation rates of single- vs. dual-coil leads and determined the associated adverse clinical outcomes, using a contemporary nation-wide ICD registry. METHODS AND RESULTS: Between July 2010 and March 2015, 6343 consecutive ICD (n = 3998) or CRT-D (n = 2345) implantation patients were prospectively enrolled in the Israeli ICD Registry. A follow-up of at least 1 year of 2285 patients was available for outcome analysis. The primary endpoint was all-cause mortality. Single-coil leads were implanted in 32% of our cohort, 36% among ICD recipients, and 26% among CRT-D recipients. Secondary prevention indication was associated with an increased rate of dual-coil implantation. A significant decline in dual-coil leads with reciprocal incline of single coils was observed, despite low rates of DFT testing (11.6%) during implantation, which also declined from 31 to 2%. In the multivariate Cox model analysis, dual- vs. single-coil lead implantation was not associated with an increased risk of mortality [hazard ratio (HR) = 1.23; P= 0.33], heart failure hospitalization (HR = 1.34; P=0.13), appropriate (HR = 1.25; P= 0.33), or inappropriate ICD therapy (HR = 2.07; P= 0.12). CONCLUSION: Real-life rates of single-coil lead implantation are rising while adding no additional risk. These results of single-coil safety are reassuring and obtained, despite low and contemporary rates of DFT testing.

Syncope in Primary Prevention Implantable Cardioverter Defibrillator Implantation.

BACKGROUND: Syncope prognosis varies widely: 1 year mortality may range from 0% in the case of vasovagal events up to 30% in the presence of heart disease. OBJECTIVES: To assess the outcomes and prognosis of patients with implantable cardiac defibrillator (ICD) and indication of primary prevention and compare patients presenting with or without prior syncope. METHODS: We reviewed the charts of 75 patients who underwent ICD implantation with the indication of primary prevention and history of syncope and compared them to a control group of 80 patients without prior syncope. We assessed the number of ventricular tachycardia (VT), ventricular fibrillation (VF), shock, anti-tachycardia pacing (ATP), and death in each group during the follow-up. RESULTS: Mean follow-up was 893 days (810-976, 95% confidence interval) (no difference between groups). Patients with prior syncope had a higher ejection fraction (EF) (35.5 ± 12.6 vs. 31.4 ± 8.76, P = 0.02), more episodes of VT (21.3% vs. 3.8%, P = 0.001) and VF (8% vs. 0%, P = 0.01) and also received more electric shocks (18.7% vs. 3.8%, P = 0.004) and ATP (17.3% vs. 6.2%, P = 0.031). There were no differences in inappropriate shocks (6.7% vs. 5%, P = 0.74), in cardiovascular mortality (cumulative 5 year estimate 29.9% vs. 32.2% P = 0.97) and any death (cumulative 5 year estimate 38.1% vs. 48.9% P = 0.18) during the follow-up. CONCLUSIONS: Syncopal patients before ICD implantation seem to have more episodes of VT/VF and shock or ATP. No mortality differences were observed.

Cardiac Resynchronization in Different Age Groups: A MADIT-CRT Long-Term Follow-Up Substudy.

BACKGROUND: Cardiac resynchronization with defibrillators (CRT-D) reduces heart failure and mortality compared with defibrillators alone. Whether this applies to all ages is unclear. METHODS AND RESULTS: We assessed the association of age on heart failure and death as a post hoc analysis of the MADIT-CRT follow-up study, in which 1,281 patients with class I/II heart failure (HF) were randomized to CRT-D or implantable cardioverter-defibrillators alone. Different age groups (<60, 60-74, and ≥75 years) were evaluated over 7 years for mortality and HF events. Among the 3 age groups, there were 399, 651, and 231 patients, respectively. We compared events with the use of a multivariate regression model. CRT-D compared with defibrillators alone significantly reduced the composite of HF or death across all age groups: <60 years: relative risk reduction (RRR) = 36%; 60-74 years: RRR = 61%; ≥75 years: RRR = 56%. CRT-D significantly reduced HF in all age groups: <60 years: RRR = 49%; 60-74 years: RRR = 62%; ≥75 years: RRR = 74%. CRT-D was associated with significant mortality reduction only in the 60-74 year age group: RRR = 59%. CONCLUSIONS: CRT-D reduced HF events and the composite of mortality or HF events during long-term follow-up in all age groups. CRT-D reduced mortality only in the 60-74 year age group.

Characteristics and outcomes of diabetic patients with an implantable cardioverter defibrillator in a real world setting: results from the Israeli ICD registry.

AIMS: There are limited data regarding the effect of diabetes mellitus (DM) on the risks of both appropriate and inappropriate implantable cardioverter defibrillator (ICD) therapy. The present study was designed to compare the outcome of appropriate and inappropriate ICD therapy in patients with or without DM. METHODS AND RESULTS: The risk of a first appropriate ICD therapy for ventricular tachyarrhythmias (including anti tachycardia pacing and shock) was compared between 764 DM and 1346 non-DM patients enrolled in the national Israeli ICD registry. We also compared the risks of inappropriate ICD therapy, and death or cardiac hospitalization between diabetic and non-diabetic patients. Diabetic patients were older, were more likely to have ischemic cardiomyopathy, lower ejection fraction, atrial fibrillation, and other co-morbidities. The 3-year cumulative incidence of appropriate ICD therapy was similar in the DM and non-DM groups (12 and 13%, respectively, p = 0.983). Multivariate analysis showed that DM did not affect the risk of appropriate ICD therapy (HR = 1.07, 95% CI 0.78-1.47, p = 0.694) or inappropriate therapy (HR = 0.72, 95% CI 0.42-1.23, p = 0.232). However, DM was associated with a 31% increased risk for death or cardiac hospitalization (p = 0.005). Results were similar in subgroup analyses including ICD and defibrillators with cardiac resynchronization therapy function recipients, primary or secondary prevention indication for an ICD. CONCLUSIONS: Despite a significant excess of cardiac hospitalizations and mortality in the diabetic population, there was no difference in the rate of ICD treatments, suggesting that the outcome difference is not related to arrhythmias.

Aortic Valve Gradient and Clinical Outcome in Patients Undergoing Transcatheter Aortic Valve Implantation for Severe Aortic Stenosis.

OBJECTIVES: To explore the relation between the baseline aortic valve gradient (AVG) as a continuous variable and clinical outcomes following transcatheter aortic valve implantation (TAVI) in general and specifically in patients with high-gradient aortic stenosis (AS). METHODS: We reviewed 317 consecutive patients who underwent TAVI at our institution. We investigated the relation between AVG as a continuous/categorical variable and outcome among all patients and in patients without low-flow low-gradient AS, using the Cox proportional hazard model adjusting for multiple prognostic variables. RESULTS: Patients had a peak AVG of 79.9 ± 22.8 mm Hg (mean 50.5 ±15.7). During a mean follow-up of 2.7 years, AVG was inversely associated with mortality and mortality or cardiac hospitalization. Every 10-mm-Hg increase in peak AVG was associated with 18% reduction in mortality (p = 0.003) and 19% reduction in mortality/cardiac hospitalization (p < 0.001). Every 10-mm-Hg increase in mean AVG was associated with a 24% reduction in both outcomes (p = 0.005 and p < 0.001). Subgroup analysis of patients with left-ventricular ejection fraction >40% or peak AVG >64 mm Hg yielded similar results. CONCLUSIONS: Mean and peak baseline AVGs are directly associated with improved outcomes after TAVI; AVG can be used to select the patients most likely to benefit from TAVI.

Type of Atrial Fibrillation and Clinical Outcomes in Patients Undergoing Transcatheter Aortic Valve Replacement.

BACKGROUND: There are limited data available regarding the relationship between atrial fibrillation (AF) clinical type, oral anticoagulation (OAC) treatment, and clinical outcome after transcatheter aortic valve replacement (TAVR). The study was designed to evaluate this relationship. METHODS: We analyzed data from the Rabin Medical Center TAVR registry, including 319 consecutive patients who underwent TAVR from 2008 to 2014. Patients were divided into three groups based on their history of AF: sinus rhythm (SR), paroxysmal AF (PAF), or nonparoxysmal AF (NPAF). RESULTS: There were 211 (66%), 56 (18%), and 52 (16%) patients in the SR, PAF, and NPAF groups, respectively. The cumulative risk for stroke or death at 2 years was highest among patients with NPAF (38%), but similarly low in PAF (15%) and SR patients (16%, P < 0.001). By multivariate analysis, patients with NPAF demonstrated a significantly higher risk of stroke or death (HR = 2.76, 95% CI 1.63-4.66, P < 0.001), as compared with SR. In contrast, patients with PAF had a similar risk of stroke or death compared with SR (HR = 0.80, P = 0.508). Patients with NPAF not treated with OAC demonstrated an 8.3-fold (P < 0.001) increased risk of stroke or death, whereas patients with PAF not treated with OAC had a similar risk of stroke or death compared with the SR group (HR = 1.25, P = 0.569). CONCLUSION: History of NPAF, but not PAF, is associated with a significant increased risk of stroke or death compared with sinus rhythm in patients undergoing TAVR.

Syncope in Primary Prevention Implantable Cardioverter Defibrillator Patients.

BACKGROUND: Syncope is a common clinical condition spanning from benign to life-threatening diseases. There is sparse information on the outcomes of syncopal patients who received an implantable cardiac defibrillator (lCD) for primary prevention of sudden cardiac death (SCD). OBJECTIVES: To assess the outcomes and prognosis of patients who underwent implantable cardiac defibrillator (ICD) implantation for primary prevention of SCD and compare them to patients who presented with or without prior syncope. METHODS: We compared the medical records of 75 patients who underwent ICD implantation for primary prevention of SCD and history of syncope to those of a similar group of 80 patients without prior syncope. We assessed the episodes of ventricular tachycardia (VT), ventricular fibrillation (VF), shock, anti-tachycardia pacing (ATP) and mortality in each group during follow-up. RESULTS: Mean follow-up was 893 days (810-976, 95% CI) (no difference between groups). There was no significant difference in gender or age. Patients with prior syncope had a higher ejection fraction rate (35.5 ? 12.6 vs. 31.4 8.76, P = 0.02), experienced more episodes of VT (21.3% vs. 3.8%, P = 0.001) and VF (8% vs. 0%, P = 0.01), and received more electric shocks (18.7% vs. 3.8%, P = 0.004) and ATP (17.3% vs. 6.2%, P = 0.031). There were no differences in inappropriate shocks (6.7% vs. 5%, P = 0.74), cardiovascular mortality (cumulative 5 year estimate 29.9% vs. 32.2%, P = 0.97) and any death (cumulative 5 year estimate 38.1% vs. 48.9%, P = 0.18). CONCLUSIONS: Patients presenting with syncope before ICD implantation seemed to have more episodes of VT/VF and shock or ATP. No differences in mortality were observed.

Mutations in cytoplasmic loops of the KCNQ1 channel and the risk of life-threatening events: implications for mutation-specific response to ß-blocker therapy in type 1 long-QT syndrome.

BACKGROUND: ß-Adrenergic stimulation is the main trigger for cardiac events in type 1 long-QT syndrome (LQT1). We evaluated a possible association between ion channel response to ß-adrenergic stimulation and clinical response to ß-blocker therapy according to mutation location. METHODS AND RESULTS: The study sample comprised 860 patients with genetically confirmed mutations in the KCNQ1 channel. Patients were categorized into carriers of missense mutations located in the cytoplasmic loops (C loops), membrane-spanning domain, C/N terminus, and nonmissense mutations. There were 27 aborted cardiac arrest and 78 sudden cardiac death events from birth through 40 years of age. After multivariable adjustment for clinical factors, the presence of C-loop mutations was associated with the highest risk for aborted cardiac arrest or sudden cardiac death (hazard ratio versus nonmissense mutations=2.75; 95% confidence interval, 1.29-5.86; P=0.009). ß-Blocker therapy was associated with a significantly greater reduction in the risk of aborted cardiac arrest or sudden cardiac death among patients with C-loop mutations than among all other patients (hazard ratio=0.12; 95% confidence interval, 0.02-0.73; P=0.02; and hazard ratio=0.82; 95% confidence interval, 0.31-2.13; P=0.68, respectively; P for interaction=0.04). Cellular expression studies showed that membrane spanning and C-loop mutations produced a similar decrease in current, but only C-loop mutations showed a pronounced reduction in channel activation in response to ß-adrenergic stimulation. CONCLUSIONS: Patients with C-loop missense mutations in the KCNQ1 channel exhibit a high risk for life-threatening events and derive a pronounced benefit from treatment with ß-blockers. Reduced channel activation after sympathetic activation can explain the increased clinical risk and response to therapy in patients with C-loop mutations.

QRS axis and the benefit of cardiac resynchronization therapy in patients with mildly symptomatic heart failure enrolled in MADIT-CRT.

BACKGROUND: Mildly symptomatic heart failure (HF) patients derive substantial clinical benefit from cardiac resynchronization therapy with defibrillator (CRT-D) as shown in MADIT-CRT. The presence of QRS axis deviation may influence response to CRT-D. The objective of this study was to determine whether QRS axis deviation will be associated with differential benefit from CRT-D. METHODS: Baseline electrocardiograms of 1,820 patients from MADIT-CRT were evaluated for left axis deviation (LAD: quantitative QRS axis -30 to -90) or right axis deviation (RAD: QRS axis 90-180) in left bundle branch block (LBBB), right bundle branch block (RBBB), and nonspecific interventricular conduction delay QRS morphologies. The primary endpoints were the first occurrence of a HF event or death and the separate occurrence of all-cause mortality as in MADIT-CRT. RESULTS: Among LBBB patients, those with LAD had a higher risk of primary events at 2 years than non-LAD patients (20% vs 16%; P = 0.024). The same was observed among RBBB patients (20% vs 10%; P = 0.05) but not in IVCD patients (22% vs 23%; P = NS). RAD did not convey any increased risk of the primary combined endpoint in any QRS morphology subgroup. When analyzing the benefit of CRT-D in the non-LBBB subgroups, there was no significant difference in hazard ratios for CRT-D versus ICD for either LAD or RAD. However, LBBB patients without LAD showed a trend toward greater benefit from CRT therapy than LBBB patients with LAD (HR for no LAD: 0.37, 95% CI: 0.26-0.53 and with LAD: 0.54, 95% CI: 0.36-0.79; P value for interaction = 0.18). CONCLUSIONS: LAD in non-LBBB patients (RBBB or IVCD) is not associated with an increased benefit from CRT. In LBBB patients, those without LAD seem to benefit more from CRT-D than those with LAD.