Anxiety disorders are associated with low vagal control of heart rate and increased risk of cardiac mortality and sudden cardiac death. This study examined whether the herbal anxiolytic, kava, produces improvement in vagal control in generalized anxiety disorder. Before and after treatment with placebo (n = 7) or kava (n = 6), two indices of vagal control were measured under supine conditions using power spectral analysis: baroreflex control of heart rate (BRC) and respiratory sinus arrhythmia (RSA). Significantly more patients treated with kava showed improved BRC compared to the placebo group (p < 0.05). Furthermore, the magnitude of improvement in BRC was significantly correlated with the degree of clinical improvement (p < 0.05). RSA did not respond to treatment. These preliminary findings suggest that kava might exert a favourable effect on reflex vagal control of heart rate in generalized anxiety disorder patients. The parallel clinical and BRC responses may reflect an underlying common effect of this herbal anxiolytic.
Billman G E, Schwartz P, Stone H L (1982) Baroreceptor reflex control of heart rate: a predictor of sudden cardiac death. Circulation66: 874–880
2.
Bristow J D, Honour A J, Pickering G W, Sleight P, Smyth H S (1969) Diminshed baroreflex sensitivity in high blood pressure. Circulation39: 48–54
3.
Cohen H, Kotler M, Matar M A, Kaplan Z, Miodownik H, Cassuto Y (1997) Power spectral analysis of heart rate variability in posttraumatic stress disorder patients. Biol Psychiatry41: 627–629
4.
De Ferrari G M, Landolina M, Mantica M, Manfredini R, Schwartz P J, Lotto A (1995) Baroreflex sensitivity, but not heart rate variability, is reduced in patients with life-threatening ventricular arrhythmias long after myocardial infarction. Am Heart J130: 473–480
5.
Goldstein D S (1983) Arterial baroreflex sensitivity, plasma catecholamines, and pressor responsiveness in essential hypertension. Circulation68: 234–240
6.
Gribbin B, Pickering T G, Sleight P, Peto R (1971) Effect of age and high blood pressure on baroreflex sensitivity in man. Circul Res29: 424–431
7.
Haines A P, Imeson J D, Meade T W (1987) Phobic anxiety and ischaemic heart disease. Br Med J295: 297–299
8.
Hamilton M (1959) The assessment of anxiety states by rating. Br J Medi Psychology32: 50–55
9.
Hohnloser S H, Klingenheben T, van de Loo A, Hablawetz E, Just H, Schwartz P J (1994) Reflex versus tonic vagal activity as a prognostic parameter in patients with sustained ventricular tachycardia or ventricular fibrillation. Circulation89: 1068–1073
10.
Hull S S, Vanoli E, Adamson P B, Verrier R L, Foreman R D, Schwartz P J (1994) Exercise training confers anticipatory protection from sudden death during acute myocardial ischemia. Circulation89: 548–552
11.
Kawachi I, Colditz G A, Ascherio A, Rimm E B, Giovannucci E, Stampfer M J, Willett W C (1994a) Prospective study of phobic anxiety and risk of coronary heart disease in men. Circulation89: 1992–1997
12.
Kawachi I, Sparrow D, Vokonas P S, Weiss S T (1994b) Symptoms of anxiety and risk of coronary heart disease: the normative aging study. Circulation90: 2225–2229
13.
Kawachi I, Sparrow D, Vokonas P S, Weiss S T (1995) Decreased heart rate variability in men with phobic anxiety (data from the normative aging study). Am J Cardiol75: 882–885
14.
Kubzansky L D, Kawachi I, Spiro A, Weiss S T, Vokonas P S, Sparrow D (1997) Is worrying bad for your heart?: a prospective study of worry and coronary heart disease in the normative aging study. Circulation95: 818–824
15.
Parati G, Frattola A, DiRienzo M, Castiglioni P, Pedotti A, Mancia G (1995) Effects of aging on 24-h dynamic baroreceptor control of heart rate in ambulant subjects. Am J Physiology268: H1606–H1612
16.
Pitler M H, Ernst E (2000) Efficacy of kava extract for treating anxiety: systematic review and meta-analysis. J Clin Psychopharmacol20: 84–89
17.
Pomeranz B, Macaulay R J B, Caudill M A, Kutz I, Adam D, Gordon D, Kilborn K M, Barger A C, Shannon D C, Cohen R J, Benson H (1985) Assessment of autonomic function in humans by heart rate spectral analysis. Am J Physiol248: H151–H153
18.
Randall O S, Esler M, Bulloch G F, Maisel A S, Ellis C N, Zweifer A J, Julius S (1976) Relationship of age and blood pressure to baroreflex sensitivity and arterial compliance in man. Clin Sci Mol Med51: 357–360
19.
Rissanen A, Naukkarinen H, Virkkunen M, Rawlings R R, Linnoila M (2000) Fluoxetine normalizes increased cardiac vagal tone in bulimia nervosa. J Clin Psychopharmacol18: 26–32
20.
Roose S P, Laghrissi-Thode F, Kennedy J S, Nelson J C, Bigger J T, Pollock B G, Gaffney A, Narayan M, Finkel M S, McCafferty J, Gergel I (1998) Comparison of paroxetine and nortriptyline in depressed patients with ischemic heart disease. JAMA279: 287–291
21.
Schwartz P, Billman G E, Stone H L (1984) Autonomic mechanisms in ventricular fibrillation induced by myocardial ischemia during exercise in dogs with healed myocardial infarction: an experimental model for sudden cardiac death. Circulation69: 790–800
22.
Sheehan D V, Raj A B, Sheehan K H, Soto S (1990) Is buspirone effective for panic disorder?J Clin Psychopharmacol10: 3–11
23.
Sheehan D V, Lecrubier Y, Sheehan K H, Amorim P, Janavs J, Weiller E, Hergueta T, Baker R, Dubar G C (1998) The Mini-International Neuropsychiatric Interview (MINI): the development and validation of a structured diagnostic psychiatric interview for DSM-IV and ICD–10. J Clin Psychiatry59: 22–33
24.
Steptoe A, Sawada Y (1989) Assessment of baroreceptor reflex function during mental stress and relaxation. Psychophysiology26: 140–147
25.
Thayer J F, Friedman B H, Borkovec T D (1996) Autonomic characteristics of generalized anxiety disorder and worry. Biol Psychiatry39: 255–266
26.
Tucker P, Adamson P, Miranda R Jr, Scarborough A, Williams D, Groff J, McLeod D (1997) Paroxetine increases heart rate variability in panic disorder. J Clin Psychopharmacol17: 370–376
27.
Vanoli E, De Ferrari G M, Stramba-Badiale M, Hull S S, Foreman R D, Schwartz P J (1991) Vagal stimulation and prevention of sudden death in conscious dogs with a healed myocardial infarction. Circul Res68: 1471–1481
28.
Watkins L L, Grossman P, Krishnan R, Sherwood A (1998) Anxiety and vagal control of heart rate. Psychosomat Med60: 498–502
29.
Watkins L L, Grossman P, Krishnan R, Blumenthal J A (1999) Anxiety reduces baroreflex cardiac control in older adults with major depression. Psychosomat Med61: 334–340
30.
Welch P D (1967) The use of fast Fourier transform for the estimation of power spectra: a method based on time averaging over short modified periodograms. IEEE Trans Audio Electroacoust15: 70–73
31.
Yeragani V K, Balon R, Pohl R, Ramesh C, Glitz D, Weinberg P, Merlos B (1990) Decreased R-R variance in panic disorder patients. Acta Psychiatr Scand81: 554–559
32.
Yeragani V K, Pohl R, Berger R, Balon R, Ramesh C, Glitz D, Srinivasan K, Weinberg P (1993) Decreased heart rate variability in panic disorder patients: a study of power-spectral analysis of heart rate. Psychiatry Res46: 89–103
33.
Yeragani V K, Jampala V C, Sobelewski E, Kay J, Igel G (1999) Effects of paroxetine on heart period variability in patients with panic disorder: a study of holter ECG records. Neuropsychobiology40: 124–128
