Ventricular late gadolinium enhancement by cardiac MRI as a predictor of atrial fibrillation in hypertrophic cardiomyopathy.

BACKGROUND: Atrial fibrillation (AF) increases stroke and mortality in patients with hypertrophic cardiomyopathy (HCM). Cardiac MRI (CMR) is increasingly used to detect late gadolinium enhancement (LGE) as a reliable indicator of left ventricular fibrosis, a potential predisposing factor of AF. Our research explored the correlation between left ventricular LGE and AF prevalence in HCM. METHODS: This retrospective study involved 351 HCM patients who underwent CMR. LGE percentages (0%, 1-5%, 6-14%, ≥15%) on CMR were compared with AF prevalence in HCM patients. Demographic, comorbidity, and imaging data were analyzed using appropriate univariate and multivariate analyses assessing for significant differences in AF prevalence. The predetermined significance level was p < 0.05. RESULTS: CMR demonstrated increased LGE in those with AF (p = 0.004). Increased LGE correlated with increased AF rates: 27.6% (0% LGE), 38.5% (1-5% LGE), 44.4% (6-14% LGE), and 54.7% (≥15% LGE) (p = 0.101, p = 0.043, p = 0.002, respectively, vs. 0% LGE). Adjusted for age, differences persisted and were most evident for LGE >15% (p = 0.001). Multivariate analysis, factoring age, gender, BMI, RVSP, and LVEF, supported LGE (odds ratio of 1.20, p = 0.036) and LAVI (odds ratio 1.05, 1.02-1.07, p < 0.001) as predictive markers for AF prevalence. CONCLUSIONS: Our study suggests a correlation between ventricular LGE and AF in patients with HCM. LGE exceeding 15% was associated with a significant increase in AF prevalence. These patients may require more frequent AF monitoring.

Four-year follow-up of outcomes of the hybrid epicardial-endocardial ablation: A single-center experience.

BACKGROUND: The CONVERGE trial demonstrated that hybrid epicardial and endocardial ablation was more effective than catheter ablation for the treatment of persistent atrial fibrillation (AF) at 1 year. Long-term real-world outcome data are scarce. OBJECTIVE: We described a single-center experience by evaluating the long-term effectiveness and safety of hybrid epicardial-endocardial ablation. METHODS: This is a retrospective single-center study. Patients were followed up to 4 years. The primary end point was the rate of AF recurrence up to 4 years postablation. Secondary end points included reduction in antiarrhythmic therapy use, the effect of the ligament of Marshall removal, epicardial posterior wall, 3-dimensional mapping during epicardial ablation, and left atrial appendage exclusion as adjunct intraoperative interventions for AF recurrence. RESULTS: Of the 170 patients, 86.5% had persistent AF and 13.5% had long-standing persistent AF. AF-free survival was 87.6% at 1 year, 76.9% at 2 years, 70.4% at 3 years, and 59.3% at 4 years. Antiarrhythmic drug use was 87.6% at baseline and reduced to 21%, 20.6%, 18%, and 14.1% at year 1, 2, 3, and 4, respectively (P < .01 for all). Three-dimensional epicardial mapping showed a significant reduction in combined recurrence from 42% to 25% over 4 years of follow-up (P = .023). Ligament of Marshall and left atrial appendage exclusion showed numerical reduction in AF recurrence from 35% to 26% (P = .49) and from 44% to 30% (P = .07). CONCLUSION: The hybrid convergent procedure reduces AF recurrence and the need for antiarrhythmic drugs and, while maintaining a good safety profile, for the treatment of persistent and long-standing persistent AF.

Importance of newer cardiac magnetic resonance-based risk markers for sudden death prevention in hypertrophic cardiomyopathy: An international multicenter study.

BACKGROUND: The sudden death (SD) risk stratification algorithm in hypertrophic cardiomyopathy (HCM) has evolved, underscored recently by novel cardiac magnetic resonance (CMR)-based risk markers (left ventricular apical aneurysm, extensive late gadolinium enhancement, and end-stage disease with systolic dysfunction) incorporated into the 2020 American Heart Association (AHA)/American College of Cardiology (ACC) HCM guidelines. OBJECTIVE: The purpose of this study was to assess the specific impact of newer, predominantly CMR-based risk markers in a large multicenter HCM population that underwent primary prevention implantable cardioverter-defibrillator (ICD) implants. METHODS: Longitudinal study of 1149 consecutive HCM patients from 6 North American and European HCM centers prospectively judged to be at high SD risk based on ≥1 AHA/ACC individual risk markers and prophylactically implanted with an ICD was performed. European Society of Cardiology (ESC) risk score was retrospectively analyzed with respect to the known clinical outcome. RESULTS: Of 1149 patients with an ICD, 162 (14%) experienced device therapy terminating ventricular tachycardia/ventricular fibrillation 4.6 ± 4.2 years after implant. CMR-based markers solely or in combination led to ICD implantation in 49 of the 162 patients (30%) experiencing device therapy. Particularly low ESC scores (<4%/5 years) would have excluded an ESC ICD recommendation for 67 patients who nevertheless experienced appropriate ICD therapy, including 26 with the CMR-based risk markers not part of the ESC formula. CONCLUSION: Identification and incorporation of novel guideline-supported CMR-based risk markers enhance selection of HCM patients for SD prevention with ICDs. Absence of CMR-based markers from the ESC risk score accounts, in part, for it not identifying many HCM patients with SD events. These data support inclusion of CMR as a routine part of HCM patient evaluation and risk stratification.

A cost comparison of atrial fibrillation monitoring strategies after embolic stroke of undetermined source.

Background: Detection of atrial fibrillation (AF) in patients with embolic stroke of undetermined source (ESUS) is challenging due to its paroxysmal nature. We sought to assess AF detection with an insertable cardiac monitor (ICM) and to perform cost analysis for various AF monitoring strategies post-ESUS We applied this cost analysis modeling to recently published Stroke AF and Per Diem trials. Methods: Retrospective chart review was performed in consecutive hospitalized patients with ESUS who had ICM placed prior to discharge. Utilizing rate of ICM-detected AF and Medicare average payments, we modeled 30-day per-patient diagnostic costs of Immediate ICM insertion prior to discharge versus using a wearable monitor followed by ICM in patients with ESUS, from Medicare and patient out-of-pocket perspectives. Similar modeling strategy and cost analysis was applied to the Stroke AF and Per Diem trials. Results: In 192 ESUS patients, AF detection increased with length of monitoring: 7.3 % at 14 days, 9.4 % at 30 days, and 17.2 % after a median ~ 6 months (189 days). Cost modeling predicted that immediate ICM leads to $3683-$4070 lower Medicare payments per-patient and $1425-$1503 lower patient out-of-pocket costs compared to Wearable-to-ICM strategies. Using similar modeling in the PER DIEM and STROKE AF trials, the additive costs of the 30-day ELR to ICM strategy ranged from $3786-$3946 from a payer perspective and $1472-$1503 from a patient out-of-pocket perspective. Conclusions: Use of ICM immediately after ESUS is cost-saving compared to Wearable-to-ICM strategies, due to the cost and low diagnostic yield of short-term wearable cardiac monitoring.

Same-day discharge after cryoballoon ablation of atrial fibrillation: A multicenter experience.

BACKGROUND: It is common practice to observe patients during an overnight stay (ONS) following a catheter ablation procedure for the treatment of atrial fibrillation (AF). OBJECTIVES: To investigate the safety and economic impact of a same-day discharge (SDD) protocol after cryoballoon ablation for treatment of AF in high-volume, geographically diverse US hospitals. METHODS: We retrospectively reviewed 2374 consecutive patients (1119 SDD and 1180 ONS) who underwent cryoballoon ablation for AF at three US centers. Baseline characteristics, acute procedure-related complications, and longer-term evaluations of safety were recorded during routine clinical follow-up. The mean cost of an ONS was used in a one-way sensitivity analysis to evaluate yearly cost savings as a function of the percentage of SDD cases per year. RESULTS: The SDD and ONS cohorts were predominately male (69% vs. 67%; p = .3), but SDD patients were younger (64 ± 11 vs. 66 ± 10; p < .0001) with lower body mass index (30 ± 6 vs. 31 ± 61; p < .0001) and CHA2 DS2 -VASc scores (1.4 ± 1.0 vs. 2.2 ± 1.4; p < .0002). There was no difference between SDD and ONS in the 30-day total complication rate (n = 15 [1.26%] versus n = 24 [2.03%]; p = .136, respectively). The most common complication was hematoma in both the SDD (n = 8; 0.67%) and ONS (n = 11; 0.93%) cohorts. Sensitivity analysis demonstrated that when 50% of every 100 patients treated were discharged the same day, hospital cost savings ranged from $45 825 to $83 813 per year across US hospitals. CONCLUSIONS: SDD following cryoballoon ablation for AF appears to be safe and is associated with cost savings across different US hospitals.

Left Atrial Volume Index Predicts Arrhythmia-Free Survival in Patients with Persistent Atrial Fibrillation Undergoing Cryoballoon Ablation.

BACKGROUND: Pulmonary vein isolation (PVI) using cryoballoon ablation (PVI-C) is increasingly performed as a first-line strategy for the treatment of patients with persistent atrial fibrillation (PersAF); however, follow-up data and predictors of procedural success are lacking. OBJECTIVE: To study the efficacy of PVI-C in patients with PersAF, focusing on predictors of procedural success. METHODS: By retrospective review, 148 consecutive patients with PersAF who underwent PVI-C were analyzed. The impact of several variables on outcome was evaluated in univariate and multivariate analyses and Cox proportional hazards regression models. RESULTS: After a mean follow-up of 19.2±10.9 months, 75 (50.7%) patients remained arrhythmia-free without the need for antiarrhythmic drug therapy. Patients with a normal left atrial volume index (LAVI) achieved a 71.0% arrhythmia-free survival. LAVI was the most powerful predictor of procedural success. CONCLUSIONS: Arrhythmia-free survival after PVI-C in select patients with PersAF are promising. Moreover, LAVI is a valuable measurement to help guide ablation strategy and predict outcome when using cryoballoon ablation.

Population Prevalence and Correlates of Prolonged QT Interval: Cross-Sectional, Population-Based Study From Rural Uganda.

OBJECTIVES: We aimed to estimate the prevalence and correlates of QT interval prolongation in rural Uganda. BACKGROUND: Major electrocardiographic abnormalities, including prolonged QT interval, have been shown to be independently predictive of adverse cardiovascular events among Western populations. Cardiovascular diseases are on the rise in sub-Saharan Africa with poorly characterized context-specific risk factors. An important question is whether ECG screening might have value in cardiovascular disease risk stratification in SSA. METHODS: We conducted a cross-sectional survey in a sample of adults participating in an ongoing whole-population cohort in Mbarara, Uganda, in 2015. Of 1,814 subjects enrolled in the parent whole-population cohort, 856 (47%) participated in the study. Participants completed 12-lead electrocardiography and cardiovascular disease risk factors assessment. We summarized sex-specific, heart rate variation-adjusted QT (QTa) defining prolonged QTa as >460 ms in women and >450 ms in men. We fit linear and logistic regression models to estimate correlates of (continuous) QTa interval length and (dichotomous) prolonged QTa. Models included inverse probability of sampling weights to generate population-level estimates accounting for study nonparticipation. RESULTS: We assessed data from 828 participants with electrocardiograms. The weighted population mean age was 38.4 years (95% confidence interval: 36.3-40.4). The weighted population was 50.4% female, 11.5% had elevated blood pressure, and 57.6% had a high-sensitivity C-reactive protein >1 mg/dl. The population mean QTa was 409.1 ms (95% confidence interval: 405.1-413.1), and 10.3% (95% confidence interval: 7.8-13.5) met criteria for prolonged QTa. Women had a higher mean QTa (421.6 ms vs. 396.3 ms; p < 0.001), and a higher proportion of women had a prolonged QTa (14.0% vs. 9.3%; p = 0.122) than did men. In multivariable-adjusted regression models, female sex and hypertension correlated with higher mean QTa and meeting criteria for prolonged QTa, respectively. CONCLUSIONS: QT interval prolongation is highly prevalent in rural Uganda and may be more common than in high-income settings. Female sex, age, and high blood pressure correlated with QT interval prolongation. Future work should assess whether genetic predisposition or environmental factors in sub-Saharan African populations contribute to prolonged QT and clarify consequences.

Low population prevalence of atrial fibrillation in rural Uganda: A community-based cross-sectional study.

OBJECTIVES: Atrial fibrillation (AF) is a major risk factor for stroke, which is the leading cause of cardiovascular mortality in sub-Saharan Africa. However, there is limited population-based epidemiological data on AF in sub-Saharan Africa. We sought to estimate the prevalence and correlates of AF in rural Uganda. METHODS: We conducted a cross-sectional study using community health fairs in 2015 targeting eight villages in rural Uganda. Study participants completed a medical history, a clinical exam, blood collection, and 12­lead electrocardiographic (ECG) screening. Of 1814 participants enrolled in a parent cohort study that includes 98% of adults residing in the geographic area, 856 attended a health fair and were included in this study. Our primary outcome was AF or atrial flutter. We modelled population prevalence of the outcome with inverse probability of treatment weighting using data collected from the full population. RESULTS: 856 (47.2%) adults in the area attended a health fair and were included in the analysis. Health fair attendees were older (42 vs 34 years, P < 0.0001), in worse self-reported health (P < 0.0001) and more likely to be female (62% vs 49%, P < 0. 0001) compared with non-attendees. After applying weights, the estimated population mean age was 37.7 ±â€¯14.9 years. 15% of the population was overweight or obese and 1.9% had left atrial enlargement on ECG. Despite this, the weighted estimate of AF was 0% (95%CI 0-0.54%). CONCLUSIONS: AF appears less prevalent in rural Uganda than in developed countries. The explanations for this finding may be genetic, environmental or related to survivorship bias.

QRS/T-wave and calcium alternans in a type I diabetic mouse model for spontaneous postmyocardial infarction ventricular tachycardia: A mechanism for the antiarrhythmic effect of statins.

BACKGROUND: The incidence of sudden arrhythmic death is markedly increased in diabetics. OBJECTIVE: The purpose of this study was to develop a mouse model for postmyocardial infarction (post-MI) ventricular tachycardia (VT) in the diabetic heart and determine the mechanism of an antiarrhythmic effect of statins. METHODS: ECG transmitters were implanted in wild-type (WT), placebo, and pravastatin-treated type I diabetic Akita mice. MIs were induced by coronary ligation, and Ca2+ transients were studied by optical mapping, and Ca2+ transients and sparks in left ventricular myocytes (VM) by the Ionoptix system and confocal microscopy. RESULTS: Burst pacing of Akita mouse hearts resulted in rate-related QRS/T-wave alternans, which was attenuated in pravastatin-treated mice. Post-MI Akita mice developed QRS/T-wave alternans and VT at 2820 ± 879 beats per mouse, which decreased to 343 ± 115 in pravastatin-treated mice (n = 13, P <.05). Optical mapping demonstrated pacing-induced VT originating in the peri-infarction zone and Ca2+ alternans, both attenuated in hearts of statin-treated mice. Akita VM displayed Ca2+ alternans, and triggered activity as well as increased Ca2+ transient decay time (Tau), Ca2+ sparks, and cytosolic Ca2+ and decreased SR Ca2+ stores all of which were in part reversed in cells from statin treated mice. Homogenates of Akita ventricles demonstrated decreased SERCA2a/PLB ratio and increased ratio of protein phosphatase (PP-1) to the PP-1 inhibitor PPI-1 which were reversed in homogenates of pravastatin-treated Akita mice. CONCLUSION: Pravastatin decreased the incidence of post-MI VT and Ca2+ alternans in Akita mouse hearts in part by revering abnormalities of Ca2+ handling via the PP-1/PPI-1 pathway.

Increased inducibility of ventricular tachycardia and decreased heart rate variability in a mouse model for type 1 diabetes: effect of pravastatin.

Although a reduction in the high-frequency (HF) component of heart rate variability (HRV) is a major complication of diabetes and a risk factor for sudden death, its relationship to ventricular tachycardia (VT) is unknown. We developed a mouse model for the study of VT and its relationship to changes in HRV in the Akita type 1 diabetic mouse. Programmed ventricular stimulation of anesthetized mice demonstrated that Akita mice were more inducible for VT compared with wild-type mice: 78.6% versus 28.6% (P = 0.007). Optical mapping of perfused hearts demonstrated multifocal breakthroughs that occasionally gave rise to short-lived rotors consistent with focal initiation and maintenance of VT. Treatment of Akita mice with pravastatin, which had been previously shown clinically to decrease ventricular ectopy and to increase HRV, decreased the inducibility of VT: 36.8% compared with 75.0% with placebo treatment (P = 0.022). The HF fraction of HRV was reduced in Akita mice (48.6 ± 5.2% vs. 70.9 ± 4.8% in wild-type mice, P = 0.005) and was increased compared with placebo treatment in pravastatin-treated mice. Pretreatment of Akita mice with the muscarinic agonist carbamylcholine or the ß-adrenergic receptor blocker propranolol decreased the inducibility of VT (P = 0.001). In conclusion, the increased inducibility of focally initiated VT and reduced HF fraction in Akita mice were partially reversed by both pravastatin treatment and pharmacologic reversal of parasympathetic dysfunction. In this new animal model for the study of the pathogenesis of VT in type 1 diabetes, pravastatin may play a role in the prevention of VT by attenuating parasympathetic dysfunction.

Standardizing the method of measuring by echocardiogram the diameter of the ascending aorta in patients with a bicuspid aortic valve.

Serial echocardiographic follow-up of patients with a bicuspid aortic valve (BAV), in addition to providing assessment of valve dysfunction, can help identify those at risk of aortic complications. However, currently there is no standardized echocardiographic method for measuring the ascending aorta. We examined the echocardiograms of 45 patients with a BAV and 45 matched controls to understand the effects of the measurement location (1, 2, and 3 cm above the sinotubular junction) and the point in the cardiac cycle (end-diastole, mid-systole, and end-systole) at which the ascending aortic measurements are made. A greater length of aorta could be measured in end-systole than in end-diastole, presumably because of aortic recoil. Using the control data for comparison, we found that more dilated ascending aortas were detected by measuring 3 cm above the sinotubular junction in the patients with a BAV (56%) than at 1 cm (42%). The increases in size between 1 and 2 cm were greater than those between 2 and 3 cm. In conclusion, we propose that all transthoracic echocardiograms should include the proximal aorta at least 2 cm and preferably 3 cm above the sinotubular junction and suggest that for standardization and optimal visualization the measurements be done at end-systole in all patients.

3D Heart: a new visual training method for electrocardiographic analysis.

This new training method is based on developing a sound understanding of the sequence in which electrical excitation spreads through both the normal and the infarcted myocardium. The student is made aware of the cardiac electrical performance through a series of 3-dimensional pictures during the excitation process. The electrocardiogram 3D Heart 3-dimensional program contains a variety of different activation simulations. Currently, this program enables the user to view the activation simulation for all of the following pathology examples: normal activation; large, medium, and small anterior myocardial infarction (MI); large, medium, and small posterolateral MI; large, medium, and small inferior MI. Simulations relating to other cardiac abnormalities, such as bundle branch block and left ventricular hypertrophy fasicular block, are being developed as part of a National Institute of Health (NIH) Phase 1 Small Business Innovation Research (SBIR) program.

Comparison of the Selvester QRS scoring system applied on standard versus high-resolution electrocardiographic recordings.

A comparison was performed between the points measured using the Selvester QRS scoring system in 60 electrocardiograms (ECGs) displayed in both a standard format as well as a 4-fold magnified (quad-plot) format. Fifty criteria (a maximum possibility of 31 points) were evaluated in each ECG. The data indicate that in 50% of the ECGs, an identical number of points were measured. However, there was a single point difference in 31%, 2 points in 15%, and more than 2 points in 4%. The differences were primarily because of points scored on the quad-plot but not on the standard ECG. Thus, a systematic underestimation of infarct size may occur when the Selvester QRS score is measured manually from a standard ECG.

Development of an automated Selvester Scoring System for estimating the size of myocardial infarction from the electrocardiogram.

Although the Selvester Scoring System for estimating the size of myocardial infarction from the standard 12-lead electrocardiogram (ECG) has potential clinical value, it has found limited application because of the difficulties in making precise and reproducible measurements. The objective of this study was to develop software to automate the Selvester Scoring System, thus allowing wider application of the technique. The study was carried out using a training set consisting of ECG data recorded from 705 individuals with and without previous myocardial infarction. Algorithms for the 50 criteria in the Selvester Scoring System were iteratively improved by comparison of scores obtained by 2 experienced cardiologist investigators with those generated by the program. The final version was evaluated in a test set consisting of 60 ECGs by comparing scores derived by cardiologist investigator with those obtained by the program. The disagreements occurred only in 1.1% of the score comparisons and in 1.6% of the specific measurements. In all cases in which a disagreement occurred, it resulted from very small differences in measurements. These results indicate that the algorithm for automated application of the Selvester Scoring System is adequate for both clinical and research applications.

Prehospital triage of acute myocardial infarction: wireless transmission of electrocardiograms to the on-call cardiologist via a handheld computer.

BACKGROUND: Use of intravenous fibrinolytic agents and percutaneous coronary interventions produce the greatest benefit when they are implemented in the first 2 hours after symptom onset. Further delays in the time to treatment typically lead to reduced benefits and poorer outcomes. METHODS: Cabarrus County Emergency Medical Service personnel complete an acute myocardial infarction case report form and assess a 12-lead electrocardiogram (ECG) to determine if ST elevation of at least 1 mV in at least 2 contiguous leads is present and then to transmit the ECG wirelessly to the emergency department (ED). The ECG is then forwarded wirelessly from the ED to the on-call cardiologist who is carrying the IPAQ handheld computer. RESULTS: Five representative patients managed using this system during the initial year of its implementation are presented. CONCLUSION: The examples included in this article illustrate that the system and technology can work if applied in a coordinated fashion using multiple disciplines including emergency medical service, cardiologists, ED personnel, and the hospital cardiac care team, which includes the catheterization laboratory call team, acute coronary care nurses, and clerical support staff.