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Cardiovascular Disease
Published in John S. Axford, Chris A. O'Callaghan, Medicine for Finals and Beyond, 2023
Delayed conduction through the bundle branches can result in incomplete or complete bundle branch block (BBB), but does not cause a bradycardia.
Bradycardia
Published in Andrea Natale, Oussama M. Wazni, Kalyanam Shivkumar, Francis E. Marchlinski, Handbook of Cardiac Electrophysiology, 2020
In patients with AV block in the setting of an acute anterior wall MI, the major determinant of the need for permanent pacing beyond symptomatic bradycardia is the presence of intraventricular conduction defects. Patients who demonstrate bundle branch block have an unfavorable prognosis and a higher risk of sudden death. Although these patients may be at risk for serious bradyarrhythmias in the post-hospitalization period, their adverse prognosis is not necessarily related to the development of high-grade AV block. These patients are at high risk for other post-MI complications, including pump failure and ventricular tachyarrhythmias. In the contemporary practice, most patients with acute anterior wall MI with AV block and BBB have LV dysfunction and thus are eligible for implantation of an implantable cardioverter-defibrillator for primary prevention of sudden death. Often, they may even be candidates for a cardiac resynchronization device.
Recognition of common arrhythmias
Published in John Edward Boland, David W. M. Muller, Interventional Cardiology and Cardiac Catheterisation, 2019
Nicholas P. Kerr, Rajesh N. Subbiah
Bundle branch block can be chronic or intermittent. Transient rate-related bundle branch blocks may occur during tachycardia or sudden heart rate acceleration. This is also referred to as rate-related aberrancy. Ashman’s phenomenon is a specific pattern of aberrant conduction, in which a wide QRS beat occurs when a short R-R interval is preceded by a long R-R interval. The wide QRS beat most often has a right bundle branch block morphology. Ashman’s phenomenon often occurs in AF where the aberrantly conducted QRS complex may be misinterpreted as a premature ventricular complex. Transient bradycardia-dependent bundle branch blocks also occur but are relatively rare. While tachycardia-related aberrancy may be physiological or pathological (such as with coronary ischaemia), transient bradycardia-dependent bundle branch block is always pathological and signifies that underlying conduction disease is present.
Assessment of the QT interval in right bundle branch block
Published in Acta Cardiologica, 2023
Patients with a diagnosis of ‘intermittent right bundle branch block’, that were confirmed by a reading cardiologist, were selected via an electronic search of an ECG data base, MUSE™ version 9.0 SP6 (General Electric, Milwaukee, WI, USA), during an arbitrarily selected 14-year period from 1 January 2004 to 31 March 2018. There were 322, 743 unique individuals in the data base during this time period. The diagnostic criteria for identification of RBBB were those of the algorithm in MUSE™TM version 9.0 SP6 (General Electric, Milwaukee, WI, USA). Inclusion criteria consisted of 12-lead ECGs with both narrow QRS complexes (<120 ms) as well as wide QRS complexes with RBBB morphology. Exclusion criteria consisted of ECGs rendering QT measurement unreliable specifically atrial fibrillation, atrial flutter or atrial tachycardia, artifacts, T-wave changes that rendered QT measurements unreliable, only one complex with normal QRS duration or RBBB morphology, or electronic pacemaker complexes.
The safety profile of FLT3 inhibitors in the treatment of newly diagnosed or relapsed/refractory acute myeloid leukemia
Published in Expert Opinion on Drug Safety, 2021
Giovanni Marconi, Maria Benedetta Giannini, Gianmarco Bagnato, Giorgia Simonetti, Claudio Cerchione, Adrián Mosquera Orgueira, Gerardo Musuraca, Giovanni Martinelli
Midostaurin, gilteritinib and quizartinib may prolong QTc interval [44–46]. Ideally, a baseline electrocardiogram should be obtained in all the patients. Longitudinal electrocardiogram monitoring should be performed; a schedule is not well defined; however, a weekly electrocardiogram for the 1st month, and thereafter a control every 2 months could be recommended for FLT3 inhibitors chronic use. Monitoring should be intensified for concomitant medications and electrolyte imbalances, fever, or diarrhea. In the case of QTc >500 ms, interrupting FLT3 inhibitors is highly recommended; however, re-administration should be planned to manage concomitant medication and other causes of QTc prolongation; some dosage modification may be required. For patients with bundle branch blocks, QTc may not reflect the risk of fatal arrhythmia, and JT interval may be more important [48]. In these patients, we recommend a baseline cardiology consultation and a plan for specialistic monitoring, instead of risking inappropriate dose modifications.
Duchenne muscular dystrophy: an overview to the cardiologist
Published in Expert Review of Cardiovascular Therapy, 2020
Fabio de Souza, Caroline Bittar Braune, Ana Paula Cassetta Dos Santos Nucera
The current guidelines published in 2018 by the DMD Care Considerations Working Group recommends cardiological evaluation since DMD diagnosis to identify incipient signs of heart disease. Follow-up should be annual for asymptomatic patients, becoming more frequent after the onset of symptoms or changes in imaging examinations [20]. Electrocardiographic evaluation is mandatory and irreplaceable for the cardiological evaluation of DMD patients. Changes on a traditional electrocardiogram include sinus tachycardia, short PR interval, increased amplitude of R waves in right precordial leads, electrical signs of right ventricular hypertrophy, and Q waves in left lateral and precordial leads (D1, aVL, V5, V6). Q waves are narrow and deep, differing from those found in patients with ischemic disease. Inappropriate sinus tachycardia is the most described finding [21]. It is also important to note that RSr’ pattern and high R waves in V1 can be common findings in children, with no association to heart disease [22,23]. However, the presence of left bundle branch block was associated with mortality in adult MV-dependent patients [24]. Significant arrhythmias in the 24-h Holter monitoring, including unsustainable atrial and ventricular tachycardia, were rare in patients with EF > 35%, with low clinical applicability in patients with preserved EF [25].