Osamu Tateishi

Apnea-related heart rate variability in congestive heart failure patients.

Sleep‐disordered breathing (SDB) causes fluctuation of the RR interval. However, the details are uncertain. We studied the characteristics of sleep‐related heart rate variation (HRV) in congestive heart failure (CHF) patients with SDB. Ambulatory electrocardiograms and data on respiration (oronasal flow, trachea sound, abdominal wall movement, and oxygen saturation) were simultaneously recorded by a multi‐channel digital recorder for 13 CHF patients (8 men and 5 women; mean age, 68 ± 4 years). Heart rate variation occurred as a result of cyclical apnea attacks between 0.005 and 0.03 Hz (apnea band). The proportion of the apnea band (% apnea) increased with the number of apnea episodes, and SDB was highly likely when the % apnea was ≥80%. Low‐flow oxygen administration effectively reduced apnea frequency, and the apnea‐related HRV also decreased. We concluded that apnea‐related HRV was useful for detecting and following SDB in CHF cases.

Shift of Atrial Reentrant Tachycardia with Transient Entrainment to an Uncommon and a Common Type of Atrial Flutter

Atrial reentrant tachycardia (ART) which demonstrated transient entrainment shifted to an uncommon type of atrial flutter (AF) with premature atrial stimulation, and then returned to ART spontaneously, Subsequently, this ART shifted to a common type of AF by rapid atrial pacing, which was further transformed into an uncommon type of AF and finally terminated by rapid atrial pacing. The mechanism of AF in clinical cases is still controversial, but in this case, AF, both uncommon and common types, is considered due to macro‐reentry within the atria. To explain (he shift of ART to AF and mutual transformation between common and uncommon type of AF, we made a schematic figure of reentry loop within (he atria of ART and AF.

HEART RATE VARIABILITY IN CONGESTIVE HEART FAILURE

Congestive heart failure (CHF) is frequently a complication of sleepdisordered breathing (SDB) such as Cheyne–Stokes respiration. Such cases have a poor prognosis (1–9). New methods of treating these patients, such as the continuous positive airway pressure (CPAP) method, have been developed and offer desirable effect (2,8). However, the diagnosis of SDB places heavy demands on both medical staff and patients because of the need for continuous overnight polysomnographic recording, and this contributes to the difficulty of treatment of SDB patients. SDB effects hemodynamic changes in the cardiovascular system and these cause fluctuation of the RR interval. We studied the characteristics of the heart rate variation of SDB patients and the clinical significance as an index for detecting SDB among CHF patients. CLIN. AND EXPER. HYPERTENSION, 24(1&2), 75–81 (2002)

Characteristics of the Circadian Rhythm of Heart Rate Variability in Patients with Sudden Cardiac Death after Myocardial Infarction

Background: Sudden cardiac death (SCD) after myocardial infarction, most commonly caused by ventricular fibrillation, is closely associated with autonomic nervous tone. However, the mechanism of SCD and its association with autonomic nervous tone and the circadian rhythm of this tone remain obscure. We examined the characteristics of autonomic nervous tone in patients with SCD using heart rate variability (HRV) analysis.

Oxygen desaturation and heart rate variability due to Cheyne-Stokes respiration in congestive heart failure patients

Cheyne-Stokes respiration is common in congestive heart failure patients and causes cyclical fluctuation of the RR interval. We studied the characteristics of apnea-related heart rate variability (apnea HRV) and the relation between apnea HRV and oxygen desaturation was examined. Ambulatory electrocardiograms and data on respiration (oronasal flow, tracheal sounds, abdominal wall movement and oxygen saturation) were simultaneously recorded by a multi-channel digital recorder for 16 congestive heart failure patients (10 men and 6 women; mean age, 68 +/- 13 years). HRV occurred as a result of cyclical apnea attacks between 0.005 and 0.03 Hz (apnea band). Apnea HRV was obtained as the power ratio of apnea HRV normalized by the very low frequency band (0.003-0.04 Hz). Apnea HRV increased with the number of apnea episodes and the oxygen desaturation index, but no relation between apnea HRV and either mean oxygen density or oxygen desaturation time was observed. We concluded that apnea HRV is a predictor of the number of apnea attacks or oxygen desaturation, but does not reflect the degree of oxygen desaturation in Cheyne-Stokes respiration.