Abstract Objectives We compared exercise echocardiography and exercise cardiac magnetic resonance imaging with simultaneous invasive pressure registration (ExCMRip ) for the assessment of pulmonary ...vascular and right ventricular (RV) function. Background Exercise echocardiography may enable early diagnosis of pulmonary vascular disease, but its accuracy is untested. Methods Exercise imaging was performed in 61 subjects (19 athletes, 9 healthy nonathletes, 8 healthy BMPR2 bone morphogenetic protein receptor type II mutation carriers, 5 patients with new or worsening dyspnea after acute pulmonary embolism, and 20 patients with chronic thromboembolic pulmonary hypertension). Echocardiographic variables included mean pulmonary artery pressure (mPAP) and systolic pulmonary artery pressure (sPAP), cardiac output (CO), RV fractional area change, tricuspid annular systolic excursion, and RV end-systolic pressure-area ratio as a surrogate measure of RV contractile reserve. ExCMRip provided measurements of CO, RV ejection fraction, mPAP, sPAP, and RV end-systolic pressure-volume ratio at rest and during exercise. Abnormal pulmonary vascular reserve was defined as mPAP/CO slope >3 mm Hg/l/min by ExCMRip. Results Echocardiographic determination of mPAP/CO was possible in 53 of 61 subjects (87%). mPAP/CO by echocardiography was higher than that obtained by ExCMRip (+0.9 mm Hg/l/min; 95% limits of agreement, −3.6 to 5.4), but enabled accurate identification of patients with abnormal pulmonary vascular reserve (area under the receiver-operating characteristic curve, 0.88 95% confidence interval (CI): 0.77 to 1.00, p < 0.0001). Simplified relationships between sPAP and exercise intensity had similar accuracy in identifying subjects with pulmonary vascular disease (area under the receiver-operating characteristic curve, 0.95 95% CI: 0.88 to 1.01, p < 0.0001). RV fractional area change by echocardiography correlated strongly with RV ejection fraction by ExCMRip , whereas a moderate correlation was found between tricuspid annular systolic excursion and RV ejection fraction. A moderate correlation was found between ratios of peak exercise to resting RV end-systolic pressure-area ratio and RV end-systolic pressure-volume ratio (r = 0.64, p < 0.0001). Conclusions Echocardiographic estimates of RV and pulmonary vascular function are feasible during exercise and identify pathology with reasonable accuracy. They represent valid screening tools for the identification of pulmonary vascular disease in routine clinical practice.
Objectives The aim of this study was to investigate whether myocardial strain echocardiography can predict ventricular arrhythmias in patients after myocardial infarction (MI). Background Left ...ventricular (LV) ejection fraction (EF) is insufficient for selecting patients for implantable cardioverter-defibrillator (ICD) therapy after MI. Electrical dispersion in infarcted myocardium facilitates malignant arrhythmia. Myocardial strain by echocardiography can quantify detailed regional and global myocardial function and timing. We hypothesized that electrical abnormalities in patients after MI will lead to LV mechanical dispersion, which can be measured as regional heterogeneity of contraction by myocardial strain. Methods We prospectively included 85 post-MI patients, 44 meeting primary and 41 meeting secondary ICD prevention criteria. After 2.3 years (range 0.6 to 5.5 years) of follow-up, 47 patients had no and 38 patients had 1 or more recorded arrhythmias requiring appropriate ICD therapy. Longitudinal strain was measured by speckle tracking echocardiography. The SD of time to maximum myocardial shortening in a 16-segment LV model was calculated as a parameter of mechanical dispersion. Global strain was calculated as average strain in a 16-segment LV model. Results The EF did not differ between ICD patients with and without arrhythmias occurring during follow-up (34 ± 11% vs. 35 ± 9%, p = 0.70). Mechanical dispersion was greater in ICD patients with recorded ventricular arrhythmias compared with those without (85 ± 29 ms vs. 56 ± 13 ms, p < 0.001). By Cox regression, mechanical dispersion was a strong and independent predictor of arrhythmias requiring ICD therapy (hazard ratio: 1.25 per 10-ms increase, 95% confidence interval: 1.1 to 1.4, p < 0.001). In patients with an EF >35%, global strain showed better LV function in those without recorded arrhythmias (−14.0% ± 4.0% vs. −12.0 ± 3.0%, p = 0.05), whereas the EF did not differ (44 ± 8% vs. 41 ± 5%, p = 0.23). Conclusions Mechanical dispersion was more pronounced in post-MI patients with recurrent arrhythmias. Global strain was a marker of arrhythmias in post-MI patients with relatively preserved ventricular function. These novel parameters assessed by myocardial strain may add important information about susceptibility for ventricular arrhythmias after MI.
Abstract Objectives The aim of this study was to compare the volumetric response and the long-term survival after cardiac resynchronization therapy (CRT) in patients with intrinsic left bundle branch ...block (LBBB) versus chronic right ventricular pacing (RVP) with respect to the presence of mechanical dyssynchrony (MD). Background Chronic RVP induces an iatrogenic LBBB and asynchronous left ventricular contraction that is potentially reversible by upgrading to CRT. Methods A total of 914 patients eligible for CRT (117 with conventional pacemakers and 797 with intrinsic LBBB) were included in the study. MD was visually assessed before CRT and was defined as the presence of either apical rocking and/or septal flash on baseline echocardiograms. Patients with a left ventricular end-systolic volume decrease of ≥15% during the follow-up were considered responders. Patients were followed for all-cause mortality during the median follow-up of 48 months (interquartile range: 29 to 66 months). Results MD was observed in 51% of patients with RVP versus 77% in patients with intrinsic LBBB (p < 0.001). Patients with RVP and MD had a similar likelihood of volumetric response as did patients with intrinsic LBBB and MD (adjusted odds ratio: 0.71; 95% confidence interval: 0.33 to 1.53; p = 0.385). There was no significant difference in long-term survival between patients with RVP and intrinsic LBBB (adjusted hazard ratio: 1.101; 95% confidence interval: 0.658 to 1.842; p = 0.714). Patients with visual MD and either intrinsic LBBB or RVP had a more favorable survival than those without MD (p < 0.001). Conclusions The likelihood of volumetric response and a favorable long-term survival of patients with RVP was similar to those of patients with intrinsic LBBB and were mainly determined by the presence of MD and not by the nature of LBBB.
Background Sudden cardiac death (SCD) is the most devastating complication of hypertrophic cardiomyopathy (HCM), but this can be prevented by an implantable cardioverter-defibrillator (ICD). The aim ...of this study is to evaluate HCM patients with ICDs for primary or secondary prevention of SCD. Methods The study population consisted of all HCM patients with an ICD in 2 tertiary referral clinics. End points during follow-up were total and cardiac mortality, appropriate and inappropriate ICD intervention, and device-related complications. Cox-regression analysis was performed to identify predictors of outcome. Results ICDs were implanted in 134 patients with HCM (mean age 44 ± 17 years, 34% women, 4.2 ± 4.8 years follow-up). Annualized cardiac mortality rate was 3.4% per year and associated with New York Heart Association class III or IV (HR 5.2 2.0-14, P = .002) and cardiac resynchronization therapy (HR 6.3 2.1-20, P = .02). Appropriate ICD interventions occurred in 38 patients (6.8%/year) and was associated with implantation for secondary prevention of SCD (HR 4.0 1.8-9.1, P = .001) and male gender (HR 3.3 1.2-9.0, P = .02). Inappropriate ICD intervention occurred in 21 patients (3.7%/year) and in 20 patients device related complications were documented (3.6%/year). Conclusion ICDs successfully abort life-threatening arrhythmias in HCM patients at increased risk of SCD with an annualized intervention rate of 6.8% per year. End-stage heart failure is the main cause of mortality in these patients. The annualized rate of inappropriate ICD intervention was 3.7% per year, whereas device-related complications occurred 3.6% per year.
Abstract Objectives The aim of this study was to compare outcomes of alcohol septal ablation (ASA) in young and elderly patients with obstructive hypertrophic cardiomyopathy (HCM). Background The ...American College of Cardiology Foundation/American Heart Association guidelines reserve ASA for elderly patients and patients with serious comorbidities. Information on long-term age-specific outcomes after ASA is scarce. Methods This cohort study included 217 HCM patients (age 54 ± 12 years) who underwent ASA because of symptomatic left ventricular outflow tract obstruction. Patients were divided into young (age ≤55 years) and elderly (age >55 years) groups and matched by age in a 1:1 fashion to nonobstructive HCM patients. Results Atrioventricular block following ASA was more common in elderly patients (43% vs. 21%; p = 0.001), resulting in pacemaker implantation in 13% and 5%, respectively (p = 0.06). Residual left ventricular outflow tract gradient, post-procedural New York Heart Association functional class, and necessity for additional septal reduction therapy was comparable between age groups. During a follow-up of 7.6 ± 4.6 years, 54 patients died. The 5- and 10-year survival following ASA was 95% and 90% in patients age ≤55 years and 93% and 82% in patients age >55 years, which was comparable to their control groups. The annual adverse arrhythmic event rate following ASA was 0.7%/year in young patients and 1.4%/year in elderly patients, which was comparable to their control groups. Conclusions ASA is similarly effective for reduction of symptoms in young and elderly patients; however, younger patients have a lower risk of procedure-related atrioventricular conduction disturbances. The long-term mortality rate and risk of adverse arrhythmic events following ASA are low, both in young and elderly patients, and are comparable to age-matched nonobstructive HCM patients.
Abstract Objectives The aim of this study was to determine the long-term outcomes (all-cause mortality and sudden cardiac death SCD) after medical therapy, alcohol septal ablation (ASA), and myectomy ...in patients with hypertrophic cardiomyopathy (HCM). Background Therapy-resistant obstructive HCM can be treated both surgically and percutaneously. But there is no consensus on the long-term effects of ASA, especially on SCD. Methods This study included 1,047 consecutive patients with HCM (mean age 52 ± 16 years, 61% men) from 3 tertiary referral centers. A total of 690 patients (66%) had left ventricular outflow tract gradients ≥ 30 mm Hg, of whom 124 (12%) were treated medically, 316 (30%) underwent ASA, and 250 (24%) underwent myectomy. Primary endpoints were all-cause mortality and SCD. Kaplan-Meier graphs and Cox regression models were used for statistical analyses. Results The mean follow-up period was 7.6 ± 5.3 years. Ten-year survival was similar in medically treated patients (84%), ASA patients (82%), myectomy patients (85%), and patients with nonobstructive HCM (85%) (log-rank p = 0.50). The annual rate of SCD was low after invasive therapy: 1.0%/year in the ASA group and 0.8%/year in the myectomy group. Multivariate analysis demonstrated that the risk for SCD was lower after myectomy compared with the ASA group (hazard ratio: 2.1; 95% confidence interval: 1.0 to 4.4; p = 0.04) and the medical group (hazard ratio: 2.3; 95% confidence interval: 1.0 to 5.2; p = 0.04). Conclusions Patients with obstructive HCM who are treated at referral centers for HCM care have good survival and low SCD risk, similar to that of patients with nonobstructive HCM. The SCD risk of patients after myectomy was lower than after ASA or in the medical group.
Long QT syndrome (LQTS) is characterized by reduced penetrance and variable QT prolongation over time, resulting in an estimate of 25% carriers of a pathogenic mutation with a normal corrected QT ...(QTc) interval on the resting electrocardiogram (ECG).
The purpose of this study was to test the hypothesis that an individualized corrected QT interval derived from 24-hour Holter data more accurately predicts carriage of a pathogenic LQTS mutation than did QT derived from a standard 12-lead ECG and corrected using the Bazett formula (QTc interval).
Carriers of a pathogenic LQTS mutation and their genotype-negative family members who had both resting ECG and Holter recordings available were included. Automated and manual measurements of QTc were performed. QTi was derived from 24-hour Holter recordings and defined as the QT value at the intersection of an RR interval of 1000 ms, with the linear regression line fitted through QT-RR data points of each individual patient.
In total, 69 patients with LQTS (23 long QT type 1, 39 long QT type 2, and 7 long QT type 3) and 55 controls were selected. Demographic characteristics were comparable. A comparison of the receiver operating characteristic curves indicates that the test added diagnostic value compared to manual measurement (P = .02) or automated measurement (P = .005). The diagnostic accuracy of manually measured QTc using conventional cutoff criteria was 72%, while it was 92% using a sex-independent QTi cutoff of 445 ms. This was caused by a 39% increase in sensitivity without compromising the specificity.
QTi derived from Holter recordings is superior to conventional QTc measured from a standard 12-lead ECG in predicting the mutation carrier state in families with LQTS.
Obesity Is a Major Determinant of Radiation Dose in Patients Undergoing Pulmonary Vein Isolation for Atrial Fibrillation Joris Ector, Octavian Dragusin, Bert Adriaenssens, Wim Huybrechts, Rik ...Willems, Hugo Ector, Hein Heidbüchel Our study evaluates the impact of obesity on the patient radiation dose during atrial fibrillation (AF) ablation procedures under fluoroscopic guidance. Effective radiation dose and lifetime attributable cancer risk were calculated from dose-area product measurements in 85 patients undergoing AF ablation guided by biplane fluoroscopy. Body mass index was a more important determinant of the patient radiation dose than total fluoroscopy time. Effective radiation doses for AF ablation procedures were 15.2 ± 7.8 mSv, 26.7 ± 11.6 mSv, and 39.0 ± 15.2 mSv in normal, overweight, and obese patients, respectively. Given the associated increase in carcinogenic risk, obesity needs to be considered in the risk-benefit ratio of AF ablation.
Objective Postsurgical atrioventricular block may complicate surgery for congenital heart defects and is generally considered permanent when persisting longer than 14 days after surgery. In this ...study, we evaluate the occurrence of spontaneous late recovery of atrioventricular conduction in postsurgical chronic atrioventricular block and discuss its clinical implications. Methods We retrospectively reviewed all cardiac surgical procedures on cardiopulmonary bypass between January 1993 and November 2010 in subjects younger than 18 years. Patients with postsurgical advanced second- or third-degree atrioventricular block persisting longer than 14 days after surgery were included. Results Of a total of 2850 cardiac surgical procedures on cardiopulmonary bypass, 59 (2.1%) were immediately complicated by chronic postsurgical atrioventricular block of advanced second (n = 4) or third degree (n = 55). In another 6 patients (0.2%), late occurrence of chronic advanced second- (n = 3) or third-degree (n = 3) atrioventricular block, without signs of any etiology other than previous surgery, was seen 0.4 to 10 years after surgery (median, 5.7 years). Late (>2 weeks) regression to either completely normal atrioventricular conduction or asymptomatic first-degree atrioventricular block occurred 3 weeks to 7 years (median, 3.1 years) after surgery in 7 (12%) patients with immediate postsurgical chronic atrioventricular block. Conclusions Complete recovery of atrioventricular conduction or regression to asymptomatic first-degree atrioventricular block occurred in 12% of patients with postsurgical chronic second- or third-degree atrioventricular block. To prevent unnecessary adverse side effects of chronic ventricular pacing and to prolong battery longevity, ventricular pacing should be minimized in patients with recovered normal atrioventricular conduction.
An acute increase in blood pressure is associated with the occurrence of premature ventricular complexes (PVCs).
We aimed to study the timing of these PVCs with respect to afterload-induced changes ...in myocardial deformation in a controlled, preclinically relevant, novel closed-chest pig model.
An acute left ventricular (LV) afterload challenge was induced by partial balloon inflation in the descending aorta, lasting 5-10 heartbeats (8 pigs; 396 inflations).
Balloon inflation enhanced the reflected wave (augmentation index 30% ± 8% vs 59% ± 6%; P < .001), increasing systolic central blood pressure by 35% ± 4%. This challenge resulted in a more abrupt LV pressure decline, which was delayed beyond ventricular repolarization (rate of pressure decline 0.16 ± 0.01 mm Hg/s vs 0.27 ± 0.04 mm Hg/ms; P < .001 and interval T-wave to peak pressure 1 ± 12 ms vs 36 ± 9 ms; P = .008), during which the velocity of myocardial shortening at the basal septum increased abruptly (ie, postsystolic shortening) (peak strain rate -0.6 ± 0.5 s(-1) vs -2.5 ± 0.8 s(-1); P < .001). It is exactly at this time of LV pressure decline, with increased postsystolic shortening, and not at peak pressure, that PVCs occur (22% of inflations). These PVCs preferentially occurred at the basal and apical segments. In the same regions, monophasic action potentials demonstrated the appearance of delayed afterdepolarization-like transient depolarizations as origin of PVCs.
An acute blood pressure increase results in a more abrupt LV pressure decline, which is delayed after ventricular repolarization. This has a profound effect on myocardial mechanics with enhanced postsystolic shortening. Coincidence with induced transient depolarizations and PVCs provides support for the mechanoelectrical origin of pressure-induced premature beats.
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