المؤلفون: Kowlgi, Gurukripa N, Ramirez, Rafael J, Kaszala, Karoly, Joslyn, Martha, Koneru, Jayanthi N, Ellenbogen, Kenneth A, Tan, Alex Y, Huizar, Jose F

المصدر: EP: Europace; May2020, Vol. 22 Issue 5, p813-820, 8p

مصطلحات موضوعية: ARRHYTHMIA diagnosis, ECHOCARDIOGRAPHY, LEFT heart ventricle, RESEARCH, CARDIOMYOPATHIES, ANIMAL experimentation, RESEARCH methodology, MEDICAL cooperation, EVALUATION research, COMPARATIVE studies, RESEARCH funding, HEART physiology, STROKE volume (Cardiac output), DOGS

مستخلص: Aims: High premature ventricular contractions (PVCs) burden does not always predict the development of PVC-cardiomyopathy (CM). We sought to evaluate post-extrasystolic potentiation (PESP) of left ventricular ejection fraction (LVEF) to predict the severity of PVC-CM in an animal model.Methods and Results: Right ventricular apical bigeminal PVCs were introduced for 12 weeks in 11 canines to induce PVC-CM. Echocardiograms were performed to obtain LVEF without ectopy (Echo-1) and during PVCs (200 and 350 ms coupling intervals, Echo-2, and Echo-3, respectively), and premature atrial contractions (PACs) (Echo-4) at baseline and after 12 weeks of bigeminal PVCs. PESP was calculated as delta-LVEF between the sinus beat post-ectopy LVEF (Echo-2, -3, and -4, respectively) and LVEF without PVC (Echo-1) at baseline and 12 weeks of high PVC burden. A hyperdynamic LV function (LVEF > 70%) was noted in all animals only with early-coupled PVCs (LVEF at 200 ms: 74.4 ± 6%) at baseline. While PVC PESP at 200 ms had a strong significant correlation with the final 12-week LVEF (R = 0.8, P = 0.003), PVC PESP at 350 ms and PAC PESP had a positive but non-significant correlation (R = 0.53, P = 0.09, and R = 0.29, P = 0.34, respectively). Premature ventricular contraction PESP at 350 ms was significantly higher after PVC-CM had developed (delta-LVEF baseline 2.7 ± 2.9% vs. 12 weeks 18.6 ± 12.3% P < 0.001).Conclusion: Bigeminal early-coupled PVCs cause hyperdynamic left ventricular function in the structurally normal canine heart due to PESP. The degree of PESP at baseline is inversely proportional to the PVC-CM severity at 12 weeks and maybe a predictor of PVC-CM as it may assess the myocardial adaptation reserve to PVCs. [ABSTRACT FROM AUTHOR]

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المؤلفون: Tan, Alex Y¹ (AUTHOR), Elharrif, Khalid¹ (AUTHOR), Cardona-Guarache, Ricardo¹ (AUTHOR), Mankad, Pranav¹ (AUTHOR), Ayers, Owen² (AUTHOR), Joslyn, Martha² (AUTHOR), Das, Anindita³ (AUTHOR), Kaszala, Karoly¹ (AUTHOR), Lin, Shien-Fong⁴ (AUTHOR), Ellenbogen, Kenneth A¹ (AUTHOR), Minisi, Anthony J¹ (AUTHOR), Huizar, Jose F¹ (AUTHOR)

المصدر: Journal of the American College of Cardiology (JACC). Jan2020, Vol. 75 Issue 1, p1-13. 13p.

مصطلحات موضوعية: *ECHOCARDIOGRAPHY, *RESEARCH, *CARDIOMYOPATHIES, *CONVALESCENCE, *VENTRICULAR remodeling, *ANIMAL experimentation, *RESEARCH methodology, *CARDIAC contraction, *EVALUATION research, *MEDICAL cooperation, *COMPARATIVE studies, *ELECTROCARDIOGRAPHY, *HEART beat, *RESEARCH funding, *ARRHYTHMIA, *DOGS

مستخلص: Background: The presence and significance of neural remodeling in premature ventricular contraction-induced cardiomyopathy (PVC-CM) remain unknown.Objectives: This study aimed to characterize cardiac sympathovagal balance and proarrhythmia in a canine model of PVC-CM.Methods: In 12 canines, the investigators implanted epicardial pacemakers and radiotelemetry units to record cardiac rhythm and nerve activity (NA) from the left stellate ganglion (SNA), left cardiac vagus (VNA), and arterial blood pressure. Bigeminal PVCs (200 ms coupling) were applied for 12 weeks to induce PVC-CM in 7 animals then disabled for 4 weeks to allow complete recovery of left ventricular ejection fraction (LVEF), versus 5 sham controls.Results: After 12 weeks of PVCs, LVEF (p = 0.006) and dP/dT (p = 0.007) decreased. Resting SNA (p = 0.002) and VNA (p = 0.04), exercise SNA (p = 0.01), SNA response to evoked PVCs (p = 0.005), heart rate (HR) at rest (p = 0.003), and exercise (p < 0.04) increased, whereas HR variability (HRV) decreased (p = 0.009). There was increased spontaneous atrial (p = 0.02) and ventricular arrhythmias (p = 0.03) in PVC-CM. Increased SNA preceded both atrial (p = 0.0003) and ventricular (p = 0.009) arrhythmia onset. Clonidine suppressed SNA and abolished all arrhythmias. After disabling PVC for 4 weeks, LVEF (p = 0.01), dP/dT (p = 0.047), and resting VNA (p = 0.03) recovered to baseline levels. However, SNA, resting HR, HRV, and atrial (p = 0.03) and ventricular (p = 0.03) proarrhythmia persisted. There was sympathetic hyperinnervation in stellate ganglia (p = 0.02) but not ventricles (p = 0.2) of PVC-CM and recovered animals versus sham controls.Conclusions: Neural remodeling in PVC-CM is characterized by extracardiac sympathetic hyperinnervation and sympathetic neural hyperactivity that persists despite normalization of LVEF. The altered cardiac sympathovagal balance is an important trigger and substrate for atrial and ventricular proarrhythmia. [ABSTRACT FROM AUTHOR]