Premature Ventricular Contractions Are Presaged by a Mechanically Abnormal Sinus Beat.

BACKGROUND: Frequent premature ventricular contractions (PVCs) can lead to cardiomyopathy; it is unclear if there are abnormal myocardial mechanics operative in the PVC and non-PVC beats. OBJECTIVES: The aim of this study was to investigate regional and global myocardial mechanics, including dyssynchrony, in patients with frequent PVCs. METHODS: Fifty-six consecutive patients referred for PVC ablation were prospectively studied. During sinus rhythm (SR) and PVC beats, left ventricular (LV) global longitudinal strain (GLS), LV dyssynchrony (measured as the SD of time to peak GLS), and dyssynergy (measured as maximum regional strain minus minimum regional strain at aortic valve closure) were quantified using 2-dimensional strain echocardiography. GLS, dyssynchrony, and dyssynergy were compared in remote SR, pre-PVC SR, PVC, and post-PVC SR beats. RESULTS: In SR beats remote from the PVC, GLS was -17.3% ± 4%, dyssynchrony was 49 ± 14 ms, and dyssynergy was 22% ± 9%. Myocardial mechanics were significantly abnormal during PVCs compared with remote SR beats (GLS -7.7% ± 3% [P < 0.001], dyssynchrony 115 ± 37 milliseconds [P < 0.001], and dyssynergy 26% ± 10% [P < 0.001]). There were significant mechanical abnormalities in the SR beat preceding the PVC, which demonstrated significantly lower LV strain (pre-PVC SR, -13% ± 4%; P < 0.001) and more dyssynchrony (pre-PVC SR, 63 ± 19 milliseconds; P < 0.001) compared with remote SR beats. Dyssynergy was significantly higher for pre-PVC SR and PVC beats compared with remote SR (pre-PVC SR, 25% ± 8% [P < 0.001]; PVC, 26% ± 10% [P < 0.001]). CONCLUSIONS: In patients with frequent PVCs, the SR beat preceding the PVC demonstrates significant mechanical abnormalities. This finding suggests that perturbations in cellular physiological processes such as excitation-contraction coupling may underlie the generation of frequent PVCs.

Dyssynchrony and Fibrosis Persist After Resolution of Cardiomyopathy in a Swine Premature Ventricular Contraction Model.

OBJECTIVES: This study sought to prospectively study the development and then regression of premature ventricular contraction (PVC)-induced cardiomyopathy, with the hypothesis that structural left ventricular (LV) changes that are of potential clinical significance may endure beyond the period of exposure to PVCs. BACKGROUND: Recovery of LV function after eradication of PVCs in PVC-induced cardiomyopathy is incompletely defined. METHODS: Fifteen swine were exposed to: 1) 50% paced PVCs from the LV lateral epicardium for 12 weeks (LV PVC, n = 5); 2) no pacing for 12 weeks (Control, n = 5); or 3) 50% paced LV PVCs for 12 weeks followed by pacing cessation for 4 weeks (Recovery, n = 5). LV function was quantified biweekly in sinus rhythm with echocardiography. Dyssynchrony was measured from pressure-volume loops at baseline and terminal studies. LV fibrosis was quantified after sacrifice. RESULTS: LV ejection fraction during sinus rhythm fell between baseline and terminal studies in the LV PVC group (65.8 ± 3.0 to 39.3 ± 3.2; p < 0.05), whereas there was no significant change in the Control group (69.6 ± 3.0 to 72.2 ± 3.0; p = NS) or after Recovery (64.5 ± 3.4% to 61.4 ± 3.4%; p = NS) groups. There was a significant increase in LV dyssynchrony measured during sinus rhythm between baseline and terminal studies in the LV PVC group (4.0 ± 1.5% to 9.0 ± 1.5%; p < 0.05); there was a similar increase in dyssynchrony that persisted 4 weeks after PVC cessation in the Recovery group (4.4 ± 1.7% to 12.8 ± 1.7%; p < 0.05). After sacrifice, percent fibrosis was higher in the LV PVC group compared with Control (5.7 ± 0.3% vs. 3.0 ± 0.3%; p < 0.05) and remained elevated in Recovery (4.1 ± 0.3% vs. 3.0 ± 0.3%; p < 0.05) despite return to baseline LV ejection fraction. CONCLUSIONS: In a swine model of PVC-induced cardiomyopathy, cessation of PVCs for 4 weeks leads to normalization of LV systolic function but significant changes in myocardial fibrosis and LV dyssynchrony during sinus rhythm persist.

Predictors of adverse outcome in patients with frequent premature ventricular complexes: The ABC-VT risk score.

BACKGROUND: No independently validated score currently exists for risk stratification of patients with frequent premature ventricular complexes (PVCs). OBJECTIVES: The purpose of this study was to develop a risk score to predict adverse events in patients with frequent PVCs. METHODS: We analyzed consecutive patients between 2012 and 2017 undergoing 14-day continuous monitoring with frequent PVCs (>5%) and concurrent echocardiography. We performed binary logistic regression to determine multivariate predictors of adverse left ventricular remodeling (left ventricular ejection fraction [LVEF] <45% or left ventricular end-diastolic volume index >75 mL/m2). A risk score was created using the log(odds ratio (OR)) of these predictors and validated prospectively to determine the risk of future adverse events in those with baseline LVEF >45%. An adverse event was defined as LVEF decline by 10%, heart failure hospitalization, or cardiovascular mortality. Two validation cohorts were used: follow-up from the original derivation cohort (cohort 1) and an independent Korean PVC registry (cohort 2). RESULTS: The derivation cohort comprised 206 patients with a mean PVC burden of 11.6% ± 6.2% and considerable daily fluctuation (minimum burden 7.3% ± 6.2% vs maximum 17.9% ± 8.0%). Independent predictors of adverse remodeling were as follows: superiorly directed PVC axis (OR 2.7; 1 point), PVC burden 10%-20% (OR 3.5; 2 points) and >20% (OR 4.4; 3 points), PVC coupling interval >500 ms (OR 4.7; 4 points), nonsustained ventricular tachycardia (OR 5.3; 4 points), which form the ABC-VT risk score. This score predicted future adverse events in both validation cohorts: cohort 1, hazard ratio 1.43; 95% confidence interval 1.19-1.73; P < .001 and cohort 2, hazard ratio 1.22; 95% confidence interval 1.05-1.42; P = .01. CONCLUSION: The ABC-VT score is a simple tool that predicts adverse left ventricular remodeling and future clinical deterioration in patients with frequent PVCs.

Standard peak-to-peak bipolar voltage amplitude criteria underestimate myocardial scar during substrate mapping with a novel microelectrode catheter.

BACKGROUND: Ventricular bipolar voltage values <0.5 and <1.0/1.5 mV (epi- and endocardium) correlating with dense scar and border zone, respectively, were established using a 3.5-mm tip catheter. Novel microelectrode catheters promise improved mapping resolution; however, whether standard voltage criteria apply to catheters with smaller electrode size and interelectrode distance remains unclear. OBJECTIVE: The purpose of this study was to determine whether traditional bipolar voltage criteria for scar apply during substrate mapping with a microelectrode catheter. METHODS: Paired bipolar and microbipolar voltage values were acquired from control swine (n = 2) using the microelectrode catheter and assessed for systemic differences. In a postinfarction swine model (n = 6), scar characteristics were compared between the bipolar maps and microbipolar maps using both standard and adjusted voltage criteria derived from the control animals. RESULTS: In control swine, although 5th percentile values for bipolar and microbipolar voltage were similar (1.12 vs 1.22 mV [left ventricular (LV) endo]; 0.88 mV vs 0.98 mV [epi]), median values were significantly greater when acquired by microbipolar electrodes (3.60 vs 6.76 mV, P = .002 [LV endo]; 2.61 vs 2.72 mV, P = .02 [epi]). Microbipolar values were systematically larger by 2.0× and 1.4× in the LV endocardium and epicardium, respectively. Application of standard voltage values to microbipolar maps in postinfarct swine underestimated scar area by approximately 41% in the LV endocardium (13.7 vs 33.4 cm2, P = .004). CONCLUSION: Bipolar voltage values acquired from microelectrodes are systemically larger than those acquired from standard catheters. New reference values should be established for these novel catheters.

Left Ventricular Dyssynchrony Predicts the Cardiomyopathy Associated With Premature Ventricular Contractions.

BACKGROUND: The pathophysiology of cardiomyopathy associated with premature ventricular contractions (PVCs) remains unclear. OBJECTIVES: This study prospectively explored cardiomyopathy development in a swine model of paced ectopic beats. METHODS: A total of 35 swine underwent pacemaker implantation. A group exposed to paced bigeminy from the right ventricular apex (RVA) for 14 weeks (RVA PVC) (n = 10) were compared with a group exposed to regular pacing from the RVA at 140 beats/min (RV-140) (n = 5) and a control group (n = 5). To test the role of ectopic beat dyssynchrony, further groups were exposed for 12 weeks to bigeminy from the right ventricular free wall (RVFW PVC) (n = 5), the left ventricular epicardium (LV Epi PVC) (n = 5) or the right atrium (premature atrial complex) (n = 5). RESULTS: After 14 weeks, the mean left ventricular ejection fraction (LVEF) was significantly lower in the RVA PVC group than in the RV-140 or control groups (p < 0.05). LVEF declined significantly in the LV Epi PVC (65.2 ± 2.4% to 39.7 ± 3.0%; p < 0.01) and RVFW PVC (66.1 ± 2.6% to 48.6 ± 2.7%; p < 0.01) groups, with final LVEF significantly lower and ventricular fibrosis significantly higher in the LV Epi PVC group compared with all others (p < 0.05). Protein levels of pRyR2, NCX-1, CaMKII-α, and PLN were up-regulated and levels of SERCA2a were down-regulated in the LV Epi PVC group compared with the control group (p < 0.05). Longer ectopic beat QRS duration and greater LV dyssynchrony were significantly associated with larger declines in LV systolic function. CONCLUSIONS: In a swine model of paced ectopic beats, PVC-induced cardiomyopathy is phenotypically distinct from a tachycardia-induced cardiomyopathy. Cardiomyopathy severity is strongly associated with severity of the hemodynamic derangement associated with the paced ectopic beats, particularly the extent of LV dyssynchrony.

Two-dimensional global longitudinal strain is superior to left ventricular ejection fraction in prediction of outcome in patients with left-sided infective endocarditis.

BACKGROUND: Impaired cardiac function is the main predictor of poor outcome in infective endocarditis (IE). Global longitudinal strain (GLS) derived from two-dimensional strain echocardiography has proven superior in prediction of long-term outcome as compared to left ventricular ejection fraction (LVEF) in valvular disease and heart failure in general. Whether measurements of cardiac deformation can predict survival in patients with IE has not previously been investigated. METHODS: The study included consecutive patients with Duke definite IE who underwent transthoracic and transesophageal echocardiography within 7 days. Clinical and echocardiographic markers associated with 1-year survival were identified using a Cox-proportional hazards model that included propensity adjustment for surgery. Reclassification statistics including receiver operating characteristic curves and net reclassification improvement were applied to LVEF and GLS, respectively. RESULTS: A cohort of 190 patients met eligibility criteria. LVEF and GLS were both prognostic markers of mortality. Independent markers of 1-year mortality were S. aureus IE (HR:2.02; 95%CI 1.11-5.72, p = .022), diabetes (HR:2.05; 95%CI 1.12-3.75, p = .020), embolic stroke (HR:3.95; 95%CI 1.93-8.10, p < .001) and LVEF<45% (HR: 3.02; 95% CI 1.70-5.38, p < .001), GLS> -15.4% (HR:2.95; 95%CI 1.52-5.72, p < .001). Adding LVEF<45% to a model with known risk factors of IE did not significantly improve risk classification, whereas addition of GLS to the model resulted in significant increase (AUC = 0.763, p < .001). CONCLUSIONS: When treatment was taken into account, LVEF<45% and GLS > -15.4% were both associated with adverse long-term outcome in left-sided IE. GLS >-15.4 % was significantly associated with 1-year mortality in the multivariate analysis. Further, GLS was superior to LVEF in risk prediction and risk discrimination of long-term outcome in patients with left-sided IE.

The impact of supraventricular ectopic complexes in different age groups and risk of recurrent atrial fibrillation after antiarrhythmic medication or catheter ablation.

INTRODUCTION: Supraventricular ectopic complexes (SVEC) are known risk factors of recurrent atrial fibrillation (AF). However, the impact of SVEC in different age groups is unknown. We aimed to investigate the risk of AF recurrence with higher SVEC burden in patients ±57years, respectively, after treatment with antiarrhythmic medication (AAD) or catheter ablation (CA). METHODS: In total, 260 patients with LVEF >40% and age ≤70 years were randomized to AAD (N=132) or CA (N=128) as first-line treatment for paroxysmal AF. All patients underwent 7-day Holter monitoring at baseline, and after 3, 6, 12, 18 and 24months and were categorized according to median age ±57years. We used multivariate Cox regression analyses and we defined high SVEC burden at 3months of follow-up as the upper 75th percentile >195SVEC/day. AF recurrence was defined as AF ≥1min, AF-related cardioversion or hospitalization. RESULTS: Age >57years were significantly associated with higher AF recurrence rate after CA (58% vs 36%, p=0.02). After CA, we observed a higher SVEC burden during follow-up in patients >57years which was not observed in the younger age group treated with CA (p=0.006). High SVEC burden at 3months after CA was associated with AF recurrence in older patients but not in younger patients (>57years: HR 3.4 [1.4-7.9], p=0.005). We did not find any age-related differences after AAD. CONCLUSION: We found that younger and older patients respond differently to CA and that SVEC burden was only associated with AF recurrence in older patients.

Higher burden of supraventricular ectopic complexes early after catheter ablation for atrial fibrillation is associated with increased risk of recurrent atrial fibrillation.

Aims: Early identification of patients who could benefit from early re-intervention after catheter ablation is highly warranted. Our aim was to investigate the association between post-procedural burden of supraventricular ectopic complexes (SVEC) and the risk of long-term atrial fibrillation (AF) recurrence. Methods and results: A total of 125 patients undergoing catheter ablation for AF were included. Patients underwent 7-day Holter recordings immediately post-procedural. The number of SVEC in post-procedural Holter recordings was categorized into quartiles: 0-72, 73-212, 213-782 and ≥ 783 SVEC/day. Long-term AF recurrence was defined as a combined endpoint of AF ≥ 1 min during follow-up Holter recordings, cardioversion or hospitalization for AF after a 3-month blanking period and within 24 months of follow-up. High post-procedural supraventricular ectopy burden was associated with an increased risk of long-term AF recurrence in a dose-dependent manner (≥ 783 SVEC: HR 4.6 [1.9-11.5], P < 0.001) irrespective of AF recurrence during the blanking period or other risk factors. In patients with early AF recurrence < 90 days after catheter ablation ectopy burden was also highly predictive of long-term AF recurrence (SVEC ≥ 213: HR 3.0 [1.3-6.7], P = 0.007). Correspondingly, patients with early AF recurrence but low ectopy burden remained at low risk of long-term AF recurrence after the blanking period. Conclusion: Our results indicate that post-procedural ectopy burden is highly associated with long-term AF recurrence and could be a potent risk marker for selection of patients for early re-ablation. Development of future ablation risk stratification and strategies should include focus on post-procedural ectopy burden.

Antiarrhythmic medication is superior to catheter ablation in suppressing supraventricular ectopic complexes in patients with atrial fibrillation.

BACKGROUND: Supraventricular ectopic complexes (SVEC) originating in the pulmonary veins are known triggers of atrial fibrillation (AF) which led to the development of pulmonary vein isolation for AF. However, the long-term prevalence of SVEC after catheter ablation (CA) as compared to antiarrhythmic medication (AAD) is unknown. Our aims were to compare the prevalence of SVEC after AAD and CA and to estimate the association between baseline SVEC burden and AF burden during 24months of follow-up. METHODS: Patients with paroxysmal AF (N=260) enrolled in the MANTRA PAF trial were treated with AAD (N=132) or CA (N=128). At baseline and 3, 6, 12, 18 and 24months follow-up patients underwent 7-day Holter monitoring to assess SVEC and AF burden. We compared SVEC burden between treatments with Wilcoxon sum rank test. RESULTS: Patients treated with AAD had significantly lower daily SVEC burden during follow-up as compared to CA (AAD: 19 [6-58] versus CA: 39 [14-125], p=0.003). SVEC burden increased post-procedurally followed by a decrease after CA whereas after AAD SVEC burden decreased and stabilized after 3months of follow-up. Patients with low SVEC burden had low AF burden after both treatments albeit this was more pronounced after CA at 24months of follow-up. CONCLUSION: AAD was superior to CA in suppressing SVEC burden after treatment of paroxysmal AF. After CA SVEC burden increased immediately post-procedural followed by a decrease whereas after AAD an early decrease was observed. Lower SVEC burden was highly associated with lower AF burden during follow-up especially after CA.

[Viral myocarditis in a man with scleroderma].

Scleroderma is a rare cause of myocarditis. We present a case of myocarditis due to scleroderma in a 48-year-old man. The patient was eventually diagnosed with viral myocarditis, as his scleroderma was well controlled, and the clinical presentation did not match prior examples of myocarditis due to scleroderma. When treating scleroderma patients with myocarditis, scleroderma should always be considered as a possible cause, as the treatment differs from other types of myocarditis.

Improved access to temporary pacing in Denmark.

INTRODUCTION: The aim was to illustrate current use of temporary pacing (TP) in Denmark by replicating a questionnaire study from 1986 and to compare the results of the two studies. MATERIAL AND METHODS: The questionnaire was sent to Danish hospitals treating patients with acute myocardial infarction (AMI). To illustrate potential changes in the indications for TP, the questionnaire included two case reports also used in 1986. RESULTS: Thirty-three of 39 hospitals returned the questionnaire. Thirty-one (94%) were able to perform transcutaneous TP, and 20 (61%) had access to transvenous TP. Transcutaneous TP was preferred in five hospitals, and transvenous TP was the procedure of choice in 15. In 1986, 13 of 74 (18%) hospitals were able to perform transcutaneous TP, and 33 of 74 (45%) had access to transvenous TP. Over the two decades, the proportion of patients with AMI undergoing TP decreased from 3.7% to 0.7% (p < 0.00001). No significant difference was found with regard to the indications for TP except for patients with posterior AMI complicated with a third degree atrioventricular block in whom a higher rate of TP was found (85%) compared with the 1986 results (56%) (p < 0.05). CONCLUSION: The proportion of hospitals with TP facilities has nearly doubled since 1986. Over the same time period, the number of Danes undergoing TP in association with AMI was reduced. At present, TP is being performed in less than 1% of AMI patients. FUNDING: Not relevant. TRIAL REGISTRATION: Not relevant.