https://www.ahajournals.org/doi/pdf/10.1161/CIR.0000000000000549

2017 AHA/ACC/HRS Guideline for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society

This report presents the first study of cardiac arrhythmias and conduction disturbance in a large group (400 patients) with sleep apnea syndrome studied between 1974 and 1979 with 24-hour Holter electrocardiography and a simultaneously recorded polygraph during late afternoon or nocturnal sleep. Of the 400, 193 patients (48%) had cardiac arrhythmias during the recorded night. The mean number of apneic events, age, weight and lowest oxygen saturation during sleep were not significantly different in those with arrhythmias. The most significant abnormalities were unsustained ventricular tachycardia in 8 patients, sinus arrest that lasted for 2.5 to 13 seconds in 43 patients, and second-degree atrioventricular conduction block in 31. Seventy-five had frequent (greater than 2 beats/min) premature ventricular contractions during sleep. Fifty patients with significant arrhythmias had a tracheostomy and were monitored again after surgery. No arrhythmia was present in these patients except for premature ventricular contractions.

Cardiac arrhythmia and conduction disturbances during sleep in 400 patients with sleep apnea syndrome.

We prospectively evaluated and followed 204 patients with syncope to determine how often a cause of syncope could be established and to define the prognosis of such patients. A cardiovascular cause was established in 53 patients and a noncardiovascular cause in 54. The cause remained unknown in 97 patients. At 12 months, the overall mortality was 14 +/- 2.5 per cent. The mortality rate (30 +/- 6.7 per cent) in patients with a cardiovascular cause of syncope was significantly higher than the rate (12 +/- 4.4 per cent) in patients with a noncardiovascular cause (P = 0.02) and the rate (6.4 +/- 2.8 per cent) in patients with syncope of unknown origin (P less than 0.0001). The incidence of sudden death was 24 +/- 6.6 per cent in patients with a cardiovascular cause, as compared with 4 +/- 2.7 per cent in patients with a noncardiovascular cause (P = 0.005) and 3 +/- 1.8 per cent in patients with syncope of unknown origin (P = 0.0002). Patients with syncope can be separated into diagnostic categories that have prognostic importance. Patients with a cardiovascular cause have a strikingly higher incidence of sudden death than patients with a noncardiovascular or unknown cause.

A Prospective Evaluation and Follow-up of Patients with Syncope

/pdf/2021-esc-guidelines-on-cardiac-pacing-and-cardiac-kz0aans6lp.pdf

2021 ESC Guidelines on cardiac pacing and cardiac resynchronization therapy.

https://www.ahajournals.org/doi/pdf/10.1161/CIR.0000000000000628

2018 ACC/AHA/HRS Guideline on the Evaluation and Management of Patients With Bradycardia and Cardiac Conduction Delay: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society

Results are reported of portable 24 hour dynamic electrocardiographic monitoring in 50 male medical students without cardiovascular disease, as defined by normal clinical and noninvasive cardiovascular examination. During waking periods, maximal sinus rates ranged from 107 to 180 beats/min (mean ± standard deviation 141 ± 17) and minimal rates from 37 to 65 beats/min (mean 53 ± 6). Maximal and minimal observed sleeping rates were, respectively, 70 to 115 (mean 86 ± 9) and 33 to 55 (mean 43 ± 5). Twenty-five subjects (50 percent) had episodes of marked sinus arrhythmia as defined by spontaneous changes in adjacent cycle lengths of 100 percent or more. Fourteen subjects (28 percent) had sinus pauses of more than 1.75 seconds, usually during sinus arrhythmia. Transient nocturnal type I second degree atrioventricular (A-V) block was noted in three subjects (6 percent). Of 28 patients (56 percent) having atrial premature beats, only 1 (2 percent) had more than 100 such beats (141) in 24 hours. Of 25 patients (50 percent) having premature ventricular contractions, only 1 (2 percent) had more than 50 such contractions (86) in 24 hours. In conclusion, frequent atrial and ventricular premature beats are unusual in a young adult male population. In contrast, bradyarrhythmias (including marked sinus arrhythmia with sinus pauses, sinus bradycardia and nocturnal A-V block) are common. These findings are useful in evaluating the clinical significance of arrhythmias detected with portable monitoring.

Arrhythmias documented by 24 hour continuous electrocardiographic monitoring in 50 male medical students without apparent heart disease.

Arrhythmias documented by 24-hour continuous ambulatory electrocardiographic monitoring in young women without apparent

Arrhythmias documented by 24-hour continuous electrocardiographic monitoring in 50 male medical students without apparent heart disease

Electrophysiologic effects of intravenous propranolol, 0.1 mg/kg, were evaluated in 18 patients with anomalous pathways utilizing intracardiac stimulation and recording. Fourteen patients had Wolff-Parkinson-White syndrome and four had concealed ventricular preexcitation. Anomalous pathway effective refractory period could be measured during the control period and after propranolol administration in nine patients and was 304 ± 7.5 (mean ± standard error of the mean) and 304 ± 8.3 msec, respectively (difference not significant). Ventricular paced 1:1 ventriculoatrial (V-A) conduction (reflecting retrograde anomalous pathway conduction) measured in 12 patients was intact during both the control period and after propranolol at rates of 170 to 200/min. Sustained paroxysmal supraventricular tachycardia was induced in 14 patients during the control period and in 10 after propranolol (in 4 of whom the tachycardia could not be sustained because of atrioventricular [A-V] nodal refractoriness). Mean cycle length of tachycardia in these 10 patients was 328 ± 18 (control) and 352 ± 19 msec (propranolol) ( P In conclusion: (1) Propranolol has an insignificant effect on both anterograde and retrograde anomalous pathway properties. (2) In most cases, propranolol does not interfere with induction of sustained circus movement tachycardia. However, it does produce a statistically significant but slight slowing of the rate of tachycardia. (3) In a minority of cases, propranolol inhibits induction of sustained paroxysmal supraventricular tachycardia by increasing A-V nodal refractoriness.

Effects of propranolol on anomalous pathway refractoriness and circus movement tachycardias in patients with preexcitation

IN THE ABSENCE of functioning anomalous connection between atria and ventricles, the A-V junction serves as the only link between these structures, allowing the atrial impulse to be transmitted to the ventricles. The A-V junction may be defined as consisting of the atrial approaches to the A-V node, the A-V node itself, and the penetrating portion of the His bundle. Total transection of the A-V junction at any point should produce A-V block, and stimulation in the presence of a normal His-Purkinje system should produce a narrow QRS. The electrophysiologic function of the A-V junction is primarily that of conduction. However, in addition, the A-V junction possesses intrinsic automaticity, allowing it to serve as a subsidiary pacemaker in the event of failure of proximal impulse formation or propagation. Under pathologic conditions, the A-V junction can serve as an ectopic pacemaker, or as a site of reentry.

Kenneth M. Rosen

Papers

Arrhythmias documented by 24 hour continuous electrocardiographic monitoring in 50 male medical students without apparent heart disease.

Arrhythmias documented by 24-hour continuous ambulatory electrocardiographic monitoring in young women without apparent

Arrhythmias documented by 24-hour continuous electrocardiographic monitoring in 50 male medical students without apparent heart disease

Effects of propranolol on anomalous pathway refractoriness and circus movement tachycardias in patients with preexcitation

Junctional tachycardia. Mechanisms, diagnosis, differential diagnosis, and management.