Effects of repeated sauna treatment on ventricular arrhythmias in patients with chronic heart failure

Circ J 2004; 68: 1146 – 1151
Effects of Repeated Sauna Treatment on Ventricular
Arrhythmias in Patients With Chronic Heart Failure
Takashi Kihara, MD; Sadatoshi Biro, MD; Yoshiyuki Ikeda, MD; Tsuyoshi Fukudome, MD; Takuro Shinsato, MD; Akinori Masuda, MD; Masaaki Miyata, MD; Shuichi Hamasaki, MD; Yutaka Otsuji, MD; Shinichi Minagoe, MD; Suminori Akiba, MD*; Chuwa Tei, MD Background
The aim of the present study was to determine whether repeated 60°C sauna treatment improves cardiac arrhythmias in chronic heart failure (CHF) patients, because ventricular arrhythmias are an important
therapeutic target in CHF.
Methods and Results
Thirty patients (59±3 years) with New York Heart Association functional class II or III CHF and at least 200 premature ventricular contractions (PVCs)/24 h assessed by 24-h Holter recordings were
studied. They were randomized into sauna-treated (n=20) or non-treated (n=10) groups. The sauna-treated group
underwent a 2-week program of a daily 60°C far infrared-ray dry sauna for 15 min, followed by 30 min bed rest
with blankets, for 5 days per week. Patients in the non-treated group had bed rest in a temperature-controlled
room (24°C) for 45 min. The total numbers of PVCs/24 h in the sauna-treated group decreased compared with
the non-treated group [848±415 vs 3,097±1,033/24 h, p<0.01]. Heart rate variability (SDNN, standard deviation
of normal-to-normal beat interval) increased [142±10 (n=16) vs 112±11 ms (n=8), p<0.05] and plasma brain
natriuretic peptide concentrations decreased [229±54 vs 419±110 pg/ml, p<0.05] in the sauna-treated group
compared with the non-treated group.
Conclusion
Repeated sauna treatment improves ventricular arrhythmias in patients with CHF.
68: 1146 – 1151)
Key Words: Heart failure; Heart rate variability; Premature ventricular contractions; Sauna
atients with chronic heart failure (CHF) have a high in many patients.19–21 Furthermore, we have demonstrated prevalence of potentially serious arrhythmias and that repeated sauna treatment improves the prognosis in P consequently, a high incidence of sudden cardiac hamsters with CHF.22It is well recognized that alterations in
death.1–4 The presence of ventricular arrhythmias defines a the neural control of the heart, characterized by decreased higher-risk patient group with either ischemic or non- vagal activity and relative sympathetic predominance, play ischemic cardiomyopathy.5–9 Antiarrhythmic medications, a key role in the occurrence of cardiac arrhythmias in pa- such as class I drugs, have been tested in myocardial infarc- tients with CHF.23 Several studies have shown that reduced tion survivors with depressed ventricular function and in heart rate variability (HRV), determined from 24-h ambu- atrial fibrillation patients with a history of congestive heart latory electrocardiographic (ECG) recordings, is associated failure, and most were found not to be helpful and may with a greater risk for ventricular fibrillation and poor prog- even increase the occurrence of arrhythmias and cardiac nosis in patients with CHF.24–27 Therefore, we prospective- mortality.10–12 Some studies have shown that amiodarone ly investigated the effects of thermal therapy on cardiac improves ventricular arrhythmias and sudden cardiac death arrhythmias and HRV in patients with CHF.
mortality in patients with CHF, yet the improvement intotal mortality remains controversial.13–15 Previous studies have demonstrated that vasodilators, such as angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, improve the prognosis and ventricular arrhyth- We studied 30 patients with CHF, aged 28–80 years mias in patients with CHF,16–18 therefore arrhythmia is an (mean age: 59±3 years): 24 patients (16 men, 8 women) had important target for therapy in patients with CHF.
idiopathic dilated cardiomyopathy and 6 (5 men, 1 woman) We have used thermal therapy with a 60°C dry sauna in had ischemic cardiomyopathy. Inclusion criteria included patients with CHF, and found that it improves hemodynam- the presence of symptomatic CHF, left ventricular ejection ic parameters, endothelial function, and clinical symptoms fraction (LVEF) <50% by echocardiography, New YorkHeart Association (NYHA) functional class II–III, and (Received April 5, 2004; revised manuscript received September 21, >200 premature ventricular contractions (PVCs) per day on 2004; accepted September 28, 2004) 24-h Holter monitoring. Seven patients were in NYHA Departments of Cardiovascular, Respiratory and Metabolic Medicine, functional class II, and the other 23 were in class III. They *Epidemiology and Preventive Medicine, Graduate School of Medi- were randomized into a sauna-treated group (n=20) or a cine, Kagoshima University, Kagoshima, Japan non-treated group (n=10). The mean number of PVCs/24 h Mailing address: Chuwa Tei, MD, Department of Cardiovascular, was 3,123±819; the mean cardiothoracic ratio (CTR) on Respiratory and Metabolic Medicine, Graduate School of Medicine,Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima 890-8520, chest radiography was 58.5±1.0% (range: 49–75%); and the mean LVEF on echocardiography was 29±2% (range: Circulation Journal Vol.68, December 2004 Sauna Improves Ventricular Arrhythmias in CHF Baseline Clinical Characteristics of the 2 Groups
Antiarrhythmic drugs (%) Mexiletine DCM, idiopathic dilated cardiomyopathy; ICM, ischemic cardiomyopathy; NYHA, New York Heart Association; SBP, systolic blood pressure; DBP, diastolic blood pressure; ACE, angiotensin-converting enzyme; NS, not significant.
All values are given as the mean ± SE. 10–48%). All patients were receiving maintenance doses of graphy, and both plasma ANP and BNP concentrations were medications for heart failure and arrhythmias, including measured by radioimmunoassay. Chest radiography (CTR) angiotensin-converting enzyme inhibitors, diuretics, and echocardiography (LVEDD, left ventricular end dias- blockers, digitalis and antiarrhythmic drugs (mexiletine), tolic dimension; LAD, left atrial dimension; LVEF) also and they were in a stable clinical condition for 1 month be- fore entering the study. They also did not have symptomaticarrhythmias. Their medications were unchanged for at least 1 month before or during this study. Written informed con- Ambulatory ECG monitoring was by 2-lead 24-h Holter sent was obtained from all patients prior to participation, monitoring (DMC-4502, Nihon Koden, Tokyo, Japan). The and the protocol was approved by the Ethics Committee of Holter tape recordings were analyzed on a full disclosure the Faculty of Medicine, Kagoshima University.
unit that printed out each individual QRS complex forsubsequent visual examination. Complete determination of PVC frequency with a description and quantification of Thermal therapy with a far infrared-ray 60°C dry sauna complex forms (multiform PVCs, couplets, and ventricular was performed as previously reported.19 Patients remained tachycardia) was undertaken by manual analysis of the full supine on a bed during the sauna for 15 min, followed by disclosure data. For the purpose of this study, PVCs were 30 min of bed rest with a blanket to keep them warm. Pa- defined as any beat of ventricular origin faster than the sinus tients were weighed before and after the sauna treatment.
rate, including the premature beats in couplets and ventricu- Oral hydration with water was used to compensate for lost lar tachycardia. Ventricular tachycardia was defined as ≥3 weight. Patients in the non-treated group remained supine consecutive premature beats at a rate of ≥100 beats/min.
on a bed in a temperature-controlled room (24°C) for There was an excellent correlation between the 2 observers with respect to determining the total number of PVCs(r=0.99), and the number of episodes of ventricular tachy- cardia (r=0.99). The technician and physician were Clinical symptoms, such as dyspnea, fatigue, sleepless- unaware of the clinical information associated with the ness, edema, appetite-loss and constipation, were evaluated recording. Reproducibilities of the results of 24-h Holter by a self-assessment quality of life (QOL) questionnaire.20 monitoring performed twice were assessed in 13 patients Each item had 4 grades: remarkably improved, improved, with CHF: total beats, r=0.99, p<0.0001; PVCs, r=0.91, no change, or worsened. Patients were classified into 3 p<0.0001; couplets, r=0.95, p<0.0001; ventricular tachy- groups based on the results of the questionnaire. Patients who answered ‘improved’ to more than 3 items weredefined as the improved group, those who answered ‘wors- ened’ for at least 1 item were defined as the worsened Time-domain parameters of HRV were analyzed on a group, and the others were defined as the unchanged group.
MARS8000 analysis system (GE Medical SystemsInformation Technologies, Milwaukee, WI, USA) from 2-lead 24-h Holter recordings. All tapes were manually A fasting blood sample was obtained in the morning to edited for exclusion of artifacts and premature beats. A measure plasma concentrations of neurohormonal factors, minimum of 18 h of analyzable data and a minimum of including catecholamines, atrial natriuretic peptide (ANP), 85% successive RR intervals were required for a tape to be and brain natriuretic peptide (BNP). Plasma catecholamine accepted as valid. The time interval between 2 consecutive (norepinephrine, epinephrine, and dopamine) concentrations QRS complexes was calculated as the normal-to-normal were measured with high-performance liquid chomato- (NN) interval. Abnormal QRS complexes and RR intervals Circulation Journal Vol.68, December 2004 Frequency of Ventricular Arrhythmias and Heart Rate Variability at Baseline and After 2 Weeks in the 2 Groups
PVCs, premature ventricular contractions; VT, ventricular tachycardia; SDNN, standard deviation of NN interval; NS, not significant.
All values are given as the mean ± SE; **p<0.01 vs baseline. Various Parameters at Baseline and After 2 Weeks in the 2 Groups
NYHA, New York Heart Association; SBP, systolic blood pressure; DBP, diastolic blood pressure; CTR, cardiothoracic ratio; LVEDD, left ventricular end diastolic dimension; LAD, left atrial dimension; LVEF, left ventricular ejection frac tion; NE, norepi-nephrine; EP, epinephrine; DOPA, dopamine; ANP, atrial natriuretic peptide; BNP, brain natriuretic peptide; NS, not significant.
All values are given as the mean ± SE; *p<0.05 vs baseline, **p<0.01 vs baseline. were replaced by a linear interpolation algorithm. The stan- inhibitor, -blockers, diuretics, nitrates, and antiarrhythmic dard deviation (SD) of all normal beat intervals and the drugs, at baseline between the 2 groups. All patients mean length of the NN intervals (SDNN) were used for enrolled completed the study. In the sauna-treated group, time-domain measures from the entire recording period.
no patient experienced dyspnea, angina pectoris or palpita- We analyzed 24 patients; 6 patients with atrial fibrillation tions. Clinical symptoms related to dyspnea, fatigue, edema, appetite-loss, constipation and insomnia wereimproved in 17 of 20 patients and unchanged in 3 patients after the 2-week sauna treatment. However, no patients had Sauna treatment was performed daily for 5 days each worsening of clinical symptoms. In the non-treated group, week, for a total of 2 weeks. All examinations were per- clinical symptoms did not change after 2 weeks.
formed before the first treatment and on the day after thelast treatment.
At baseline, the total number of PVCs, couplets and episodes of ventricular tachycardia per day were similar All data are expressed as the mean ± SEM. Differences between the 2 groups (Table 2). In the sauna-treated group, in baseline characteristics were evaluated by the chi-square the total number of PVCs decreased in all patients 2 weeks test and unpaired t-test. Within-group changes between after treatment. The total number of PVCs in the sauna- baseline and after 2 weeks were evaluated by paired t-test treated group was significantly decreased compared with or Wilcoxon signed rank test for variables that were not the non-treated group after 2 weeks (p<0.01, Table 2). The normally distributed. Between-group comparisons were total number of couplets and episodes of ventricular tachy- evaluated by Mann-Whitney’s U test using differences cardia per day also decreased significantly in the sauna- between baseline and after 2 weeks. A value of p<0.05 was treated group compared with the non-treated group considered statistically significant.
(Table 2). The prevalence of couplets and ventriculartachycardia in the sauna-treated group compared with the non-treated group was 45% vs 90%, p<0.05, and 20% vs80%, p<0.01, respectively. The total number of PACs did Baseline Clinical Characteristics and Assessment of not significantly change between the 2 groups after 2 weeks Baseline clinical characteristics are summarized in Table 1. There were no differences in age, gender, NYHA functional class, mean heart rate, blood pressure or use of There was no difference in SDNN at the baseline drugs, such as digoxin, angiotensin-converting enzyme between the 2 groups, but after 2 weeks, SDNN was sig- Circulation Journal Vol.68, December 2004 Sauna Improves Ventricular Arrhythmias in CHF nificantly greater in the sauna-treated group compared with with CHF.22 We suggest that improvement of ventricular arrhythmias may be one of the mechanisms by which re-peated thermal therapy improves the prognosis in patients At baseline, there were no differences in the plasma con- Although the mechanisms of ventricular arrhythmias centrations of ANP, BNP, or catecholamine between the 2 occurring in patients with CHF are still unclear, experimen- groups. After 2 weeks, there were no differences in the tal evidence suggests that the development of delayed and plasma concentrations of ANP or catecholamine between early afterdepolarization-induced triggered activity and the 2 groups, but the plasma concentration of BNP in the automaticity, in addition to conditions favoring reentry, are sauna-treated group was significantly lower than in the non- related to arrhythmias in the setting of heart failure. Modu- treated group (229±54 pg/ml vs 419±110 pg/ml, p<0.05; lating factors, such as sympathetic activation, electrolyte disturbances and chronic left ventricular stretch, are alsopresent in the setting of heart failure.39,40 It is well-estab- NYHA Functional Class, Chest Radiography, Echocardio- lished that the sympathetic nervous system is activated in patients with CHF41–43 and analysis of HRV provides im- At baseline, there were no differences in NYHA func- portant information about sympathetic nervous activity in tional class, CTR or LVEDD between the 2 groups, but these patients.25,44 Data from the recent United Kingdom- after 2 weeks, there was a significant difference in NYHA Heart failure Evaluation and Assessment of Risk Trial functional class, body weight, and CTR in the sauna-treated (UK-HEART) suggest that reduced HRV, analyzed by a group; LVEDD did not change between the 2 groups.
traditional time-domain method (including SDNN), is Laboratory parameters, including liver function tests related to the risk of ventricular arrhythmias and sudden (aspartate aminotransferase, alanine aminotransferase, death in patients with CHF,24 and we suggest that one of the mechanisms by which repeated sauna treatment significant- creatinine, electrolytes (Na, Cl, K) and hematocrit, did not ly improves ventricular arrhythmias is by increasing HRV, change after 2 weeks in either group (data not shown).
although we have not clarified the underlying mechanismsof that effect of thermal therapy. On the other hand, the Discussion
self-assessment QOL questionnaire revealed 17 of 20 pa-tients who answered ‘improved’ to more than 3 of 6 clinical In the present study, we found that repeated 60°C sauna symptoms that comprised dyspnea, fatigue, sleeplessness, treatment improved ventricular arrhythmias. Furthermore, edema, appetite-loss and constipation, and furthermore, we observed that thermal therapy increased HRV and none of the patient answered ‘worsened’ for any symptom.
reduced the plasma concentration of BNP in patients with Therefore, the improvement may be related to better mood as a result of repeated sauna treatment. Further study is The incidence of ventricular arrhythmias is extremely high in patients with CHF: approximately 80% or more of The chronic stretch of cardiac myocytes contributes to CHF patients have frequent ventricular premature beats shortening of the action potential duration and mild de- and approximately 50% of them have runs of nonsustained creases in the action potential amplitude and resting mem- ventricular tachycardia.3,28–30 Sudden death because of brane potential.45 These changes may be arrhythmogenic by ventricular arrhythmias accounts for approximately half of increasing reentry and abnormal automaticity.46 In patients all deaths in patients with CHF.4,31–33 Several studies have with CHF, the ventricular wall is chronically stretched shown an association between ventricular arrhythmias and because of increases in ventricular volume and/or pressure mortality in patients with CHF,5–9,34–36 but unfortunately, overload. It is well-established that BNP is secreted pre- current antiarrhythmic medications, such as class I drugs, dominantly by the ventricle in response to ventricular wall have only limited efficacy in these patients and may even stretch.47 On the basis of our findings, including previous be associated with worsening ectopic activity and hemo- data,20 which showed significantly decreased plasma con- dynamic deterioration.10–12 In large randomized trials with centrations of BNP after 2 weeks of sauna treatment, we amiodarone, a potent antiarrhythmic drug with additional speculate that another mechanism responsible for decreased sympatholytic and minor negative inotropic effects, the ventricular arrhythmias may be reduction of ventricular Group for the Study of Survival in Heart Failure in Argentina (GESICA) demonstrated that low doses reduced Electrolyte disturbances, such as hypokalemia and hypo- ventricular arrhythmias and mortality in patients with magnesemia, are prevalent in patients treated with diuretics CHF;13 however, the Survival Trial of Antiarrhythmic and are implicated as a cause of ventricular arrhythmias Therapy in Congestive Heart Failure had conflicting results associated with CHF. However, we did not observe signifi- concerning mortality.14 Previous studies have demonstrated cant changes in the electrolyte concentrations after 2 weeks -blockers, which also have antiarrhythmic effects, reduce mortality and the risk of sudden cardiac death, as We have treated many CHF patients with sauna therapy well as ventricular arrhythmias, in patients with CHF37 and and so far none of the in-hospital patients has shown any other studies have shown that ventricular arrhythmias in deterioration in their condition. However, thermal therapy patients with CHF are improved by treatment with non- does not appear to be indicated for CHF patients with aortic antiarrhythmic drugs, such as angiotensin-converting en- stenosis or obstructive hypertrophic cardiomyopathy be- zyme inhibitors16–18 and spironolactone.38 Our present cause the pressure gradient is increased. In the present results demonstrated that thermal therapy reduced the total study, only CHF patients with NYHA functional class II or number of PVCs, couplets, and episodes of ventricular III underwent sauna treatment. It is well-known that the tachycardia in patients with CHF and we have already more severe the CHF, the more prevalent are ventricular shown that thermal therapy reduced mortality in hamsters arrhythmias. We evaluated the effects of sauna therapy on Circulation Journal Vol.68, December 2004 ventricular arrhythmias at 2 weeks, but further studies of 325: 303 – 310.
the long-term effects and benefit in CHF patients with 19. Tei C, Horikiri Y, Park JC, Jeong JW, Chang KS, Toyama Y, et al.
Acute hemodynamic improvement by thermal vasodilation in conges- NYHA functional class IV are needed.
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In conclusion, repeated 60°C sauna treatment decreased 20. Kihara T, Biro S, Imamura M, Yoshifuku S, Takasaki K, Ikeda Y, et ventricular arrhythmias in CHF patients with NYHA func- al. Repeated sauna treatment improves vascular endothelial and car- diac function in patients with chonic heart failure. J Am Coll Cardiol
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21. Tei C, Tanaka N. Thermal vasodilation as a treatment of congestive heart failure: A novel approach. J Cardiol 1996; 27: 29 – 30.
22. Ikeda Y, Biro S, Kamogawa Y, Yoshifuku S, Kihara T, Minagoe S, This study was supported in part by a Grant-in-Aid from the Japan et al. Effect of repeated sauna therapy on survival in TO-2 cardio- Heart Foundation/Pfizer Grant for Cardiovascular Disease Research. myopathic hamsters with heart failure. Am J Cardiol 2002; 90: 343 –
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Circulation Journal Vol.68, December 2004

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