Abnormalities in beat-to-beat dynamics of heart rate before the spontaneous onset of life-threatening ventricular tachyarrhythmias in patients with prior myocardial infarction

Beat-to-beat analysis of RR intervals can reveal patterns of heart-rate dynamics, which are not easily detected by summary measures of heart-rate variability. This study was designed to test the hypothesis that alterations in RR-interval dynamics occur before the spontaneous onset of ventricular tac...

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Bibliographic Details
Published in:	Circulation (New York, N.Y.) Vol. 93; no. 10; pp. 1836 - 1844
Main Authors:	HUIKURI, H. V, SEPPÄNEN, T, KOISTINENM. J, AIRAKSINEN, K. E. J, IKÄHEIMO, M. J, CASTELLANOS, A, MYERBURG, R. J
Format:	Journal Article
Language:	English
Published:	Hagerstown, MD Lippincott Williams & Wilkins 15-05-1996 American Heart Association, Inc
Subjects:	Aged Biological and medical sciences Blood and lymphatic vessels Cardiology. Vascular system Diseases of the peripheral vessels. Diseases of the vena cava. Miscellaneous Electrocardiography Female Heart Rate Humans Male Medical sciences Middle Aged Myocardial Infarction - physiopathology Tachycardia, Ventricular - physiopathology Human Arrhythmia Infarct Cardiovascular disease Exploration Coronary heart disease Myocardial disease Excitability disorder RR interval Heart rate Electrodiagnosis Heart disease Electrocardiography Myocardium Complication Paroxysmal ventricular tachycardia
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Summary:	Beat-to-beat analysis of RR intervals can reveal patterns of heart-rate dynamics, which are not easily detected by summary measures of heart-rate variability. This study was designed to test the hypothesis that alterations in RR-interval dynamics occur before the spontaneous onset of ventricular tachyarrhythmias (VT). Ambulatory ECG recordings from 15 patients with prior myocardial infarction (MI) who had spontaneous episodes of sustained VT during the recording and VT inducible by programmed electrical stimulation (VT group) were analyzed by plotting each RR interval of a sinus beat as a function of the previous one (Poincaré plot). Poincaré plots were also generated for 30 post-MI patients who had no history of spontaneous VT events and no inducible VT (MI control subjects) and for 30 age-matched subjects without heart disease (normal control subjects). The MI control subjects and VT group were matched with respect to age and severity of underlying heart disease. All the healthy subjects and MI control subjects showed fan-shaped Poincaré plots characterized by an increased next-interval difference for long RR intervals relative to short ones. All the VT patients had abnormal plots: 9 with a complex pattern, 3 ball-shaped, and 3 torpedo-shaped. Quantitative analysis of the Poincare plots showed the SD of the long-term RR-interval variability (SD2) to be smaller in all VT patients (52+/-14 ms; range, 31 to 75 ms) than in MI control subjects (110+/-24 ms; range, 78 to 179 ms, P<.001) or the normal control subjects (123+/-38 ms, P<.001), but the SD of the instantaneous beat-to-beat variability (SD1) did not differ between the groups. The complex plots were caused by periods of alternating sinus intervals, resulting in an increased SD1/SD2 ratio in the VT group. This ratio increased during the 1-hour preceding the onset of 27 spontaneous VT episodes (0.43+/-0.20) compared with the 24-hour average ratio (0.33+/-0.19) (P<.01). Reduced long-term RR-interval variability, associated with episodes of beta-to-beat sinus alternans, is a highly specific sign of a propensity for spontaneous onset of VT, suggesting that abnormal beat-to-beat heart-rate dynamics may reflect a transient electrical instability favoring the onset of VT in patients conditioned by structurally abnormal hearts.
Bibliography:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	0009-7322 1524-4539
DOI:	10.1161/01.CIR.93.10.1836