BACKGROUND: The mechanisms of the atrial contractile dysfunction induced by atrial fibrillation (AF) are not completely understood. In particular, the relation between the atrial dysfunction and electrical remodeling has not yet been studied. METHODS AND RESULTS: Seven goats were chronically instrumented with electrodes sutured to the atria and with ultrasonic piezoelectric crystals to record the atrial diameters. A pressure transducer was implanted in the right atrium. After 5 minutes, 3 hours, and throughout the first 5 days of artificially maintained AF, atrial contractile function was measured and the atrial effective refractory period (AERP) was monitored for comparison. Also, the positive inotropic effects of the L-type Ca2+-channel agonist BayY5959 and short trains of rapid atrial pacing were studied. After resumption of sinus rhythm, the recovery of atrial contractile function was followed. After 5 minutes of AF, atrial contractility was decreased by approximately 55% but recovered completely within 10 minutes. Five days of AF nearly completely abolished the atrial contractile function, and recovery took 2 days. During the first days of AF, the development of the contractile dysfunction followed the same time course as the shortening of AERP (electrical remodeling). In remodeled atria, BayY5959 increased atrial contractility to the same extent as it prolonged AERP. The inotropic effect of short trains of rapid atrial pacing was similar in normal and remodeled atria. CONCLUSIONS: Depending on the duration of AF, different mechanisms contribute to the AF-induced atrial hypocontractility. Atrial contractile remodeling during several days of AF goes hand in hand with electrical remodeling and might be caused by a reduction of the L-type Ca2+-current.
BACKGROUND: The mechanisms of the atrial contractile dysfunction induced by atrial fibrillation (AF) are not completely understood. In particular, the relation between the atrial dysfunction and electrical remodeling has not yet been studied. METHODS AND RESULTS: Seven goats were chronically instrumented with electrodes sutured to the atria and with ultrasonic piezoelectric crystals to record the atrial diameters. A pressure transducer was implanted in the right atrium. After 5 minutes, 3 hours, and throughout the first 5 days of artificially maintained AF, atrial contractile function was measured and the atrial effective refractory period (AERP) was monitored for comparison. Also, the positive inotropic effects of the L-type Ca2+-channel agonist BayY5959 and short trains of rapid atrial pacing were studied. After resumption of sinus rhythm, the recovery of atrial contractile function was followed. After 5 minutes of AF, atrial contractility was decreased by approximately 55% but recovered completely within 10 minutes. Five days of AF nearly completely abolished the atrial contractile function, and recovery took 2 days. During the first days of AF, the development of the contractile dysfunction followed the same time course as the shortening of AERP (electrical remodeling). In remodeled atria, BayY5959 increased atrial contractility to the same extent as it prolonged AERP. The inotropic effect of short trains of rapid atrial pacing was similar in normal and remodeled atria. CONCLUSIONS: Depending on the duration of AF, different mechanisms contribute to the AF-induced atrial hypocontractility. Atrial contractile remodeling during several days of AF goes hand in hand with electrical remodeling and might be caused by a reduction of the L-type Ca2+-current.
Authors: Svetlana N Reilly; Xing Liu; Barbara Casadei; Ricardo Carnicer; Alice Recalde; Anna Muszkiewicz; Raja Jayaram; Maria Cristina Carena; Rohan Wijesurendra; Matilde Stefanini; Nicoletta C Surdo; Oliver Lomas; Chandana Ratnatunga; Rana Sayeed; George Krasopoulos; Timothy Rajakumar; Alfonso Bueno-Orovio; Sander Verheule; Tudor A Fulga; Blanca Rodriguez; Ulrich Schotten Journal: Sci Transl Med Date: 2016-05-25 Impact factor: 17.956
Authors: Mihail G Chelu; Satyam Sarma; Subeena Sood; Sufen Wang; Ralph J van Oort; Darlene G Skapura; Na Li; Marco Santonastasi; Frank Ulrich Müller; Wilhelm Schmitz; Ulrich Schotten; Mark E Anderson; Miguel Valderrábano; Dobromir Dobrev; Xander H T Wehrens Journal: J Clin Invest Date: 2009-07 Impact factor: 14.808
Authors: Sotirios Nedios; Frank Lindemann; Jordi Heijman; Harry J G M Crijns; Andreas Bollmann; Gerhard Hindricks Journal: Herz Date: 2021-07-05 Impact factor: 1.443