Slow breathing training reduces resting blood pressure and the pressure responses to exercise.

Slow breathing training reduces resting blood pressure, probably by modifying central autonomic control, but evidence for this is lacking. The pressor response to static handgrip exercise is a measure of autonomic control and the aim of this study was to determine whether slow breathing training modulates the pressor responses to exercise of untrained muscles. Twenty hypertensive patients trained for 8 weeks, 10 with unloaded slow breathing (Unloaded) and 10 breathing against an inspiratory load of 20 cm H(2)O (Loaded). Ten subjects were untrained controls. Subjects performed a 2 min handgrip pressor test (30 % MVC) pre- and post-training, and blood pressure and heart rate (HR) were measured before the contraction, at the end and following 2 min recovery. Resting systolic (sBP) and HR were reduced as a result of training, as reported previously. After training there was both a smaller pressor response to hand grip exercise and a more rapid recovery of sBP and HR compared to pre-training. There were no changes in the Controls and no differences between the Unloaded and Loaded groups. Combining the two training groups, the sBP response to handgrip exercise after training was reduced by 10 mm Hg (95 % CI: -7, -13) and HR by 5 bpm (95 % CI: -4, -6), all p<0.05. These results are consistent with slow breathing training modifying central mechanisms regulating cardiovascular function.

One-year outcome following biological or mechanical valve replacement for infective endocarditis.

BACKGROUND: Nearly half of patients require cardiac surgery during the acute phase of infective endocarditis (IE). We describe the characteristics of patients according to the type of valve replacement (mechanical or biological), and examine whether the type of prosthesis was associated with in-hospital and 1-year mortality. METHODS AND RESULTS: Among 5591 patients included in the International Collaboration on Endocarditis Prospective Cohort Study, 1467 patients with definite IE were operated on during the active phase and had a biological (37%) or mechanical (63%) valve replacement. Patients who received bioprostheses were older (62 vs 54years), more often had a history of cancer (9% vs 6%), and had moderate or severe renal disease (9% vs 4%); proportion of health care-associated IE was higher (26% vs 17%); intracardiac abscesses were more frequent (30% vs 23%). In-hospital and 1-year death rates were higher in the bioprosthesis group, 20.5% vs 14.0% (p=0.0009) and 25.3% vs 16.6% (p<.0001), respectively. In multivariable analysis, mechanical prostheses were less commonly implanted in older patients (odds ratio: 0.64 for every 10years), and in patients with a history of cancer (0.72), but were more commonly implanted in mitral position (1.60). Bioprosthesis was independently associated with 1-year mortality (hazard ratio: 1.298). CONCLUSIONS: Patients with IE who receive a biological valve replacement have significant differences in clinical characteristics compared to patients who receive a mechanical prosthesis. Biological valve replacement is independently associated with a higher in-hospital and 1-year mortality, a result which is possibly related to patient characteristics rather than valve dysfunction.

Revisiting the effect of referral bias on the clinical spectrum of infective endocarditis in adults.

Referral bias occurs because of the clustering of patients at tertiary care centers. This may result in the distortion of observed clinical manifestations of rare diseases. This analysis evaluates the effect of referral bias on the epidemiology of infective endocarditis (IE) in the International Collaboration on Endocarditis-Prospective Cohort Study (ICE-PCS). This is a prospective multicenter cohort study comparing transferred and non-transferred patients with IE. Factors independently associated with transfer status were evaluated using multivariable logistic regression. A total of 2,760 patients were included in the analysis, of which 1,164 (42.2%) were transferred from other medical centers. Transferred patients more often underwent surgery for IE (odds ratio [OR] = 2.5; 95% confidence interval [CI] 1.9-3.2). They were also more likely to have complications such as stroke (OR = 1.5; 95% CI 1.3-1.9), heart failure (OR = 1.4; 95% CI 1.1-1.6), and new valvular regurgitation (OR = 1.3; 95% CI 1.1-1.6). The in-hospital mortality rates were similar in both groups. Patients with IE who require surgery and suffer complications are referred to tertiary hospitals more frequently than patients with an uncomplicated course. Hospital transfer has no obvious effect on the in-hospital mortality. Referral bias should be taken into consideration when describing the clinical spectrum of IE.

Perivalvular abscesses due to Staphylococcus aureus endocarditis comparison with Streptococcus viridans endocarditis and incremental value of transesophageal echocardiography.

BACKGROUND: Perivalvular abscesses are major complications of infective endocarditis (IE). The prevalence and best approach to detection of this complication in Staphylococcus aureus (SA) in comparison to Streptococcus viridans (SV) IE is unclear. METHOD: Among 243 consecutive episodes of IE diagnosed using the Duke criteria, who underwent either transthoracic (TTE) or transesophageal echocardiography (TEE) at the Mayo Clinic between 1988 and 1993, there were 64 cases of SV and 61 of SA IE. Comparison of TTE and TEE detection of abscesses were restricted to patients with either surgical or autopsy examination and both TTE and TEE were performed. RESULTS: Prosthetic valve and valve repair were significantly higher in SA compared to SV IE (46 vs 23%, P = 0.008). The prevalence of abscesses was higher in SA compared to SV IE (42 vs 14%, P = 0.08). 1 (10%) of abscess detected by TTE in SA compared to 1 (50%) in SV IE and 6 (60%) by TEE in SA and 1 (50%) in SV IE. Incremental value of TEE vs TTE was higher in SA 5/24 (21%) than in SV IE 0/14 (0%) P = 0.067. Hospital mortality was significantly higher in SA than SV IE (13 vs 2%, P = 0.013). CONCLUSION: Patients diagnosed with IE and those with SA 1) presented more often with prosthetic valve IE, 2) developed more perivalvular abscesses, and 3) had a higher in hospital mortality than those with SV. Incremental value of TEE was higher in SA than in SV IE, 4) therefore, had a stringent requirement for initial and repeated TEE to detect this ominous complication of IE.

Prevalence of cardiac arrhythmias in Thai community.

The resting 12 leads electrocardiogram was recorded in 3,822 men and 4,969 women (aged 30 years or over), who participated in the First National Health Examination Survey of Thailand and the data was used to determine the prevalence of cardiac arrhythmias. In this apparently normal population 362 subjects (the standard age adjusted rate was 39.2 per thousand) had cardiac arrhythmia. The prevalence rate of atrial fibrillation was 3.6 per thousand (males 3.6, females 3.6) and ventricular premature beat was 12.1 per thousand (males 7.3, females 15.6). For atrial premature beat, complete and incomplete right bundle branch blocks, sinus arrhythmia, first degree atrioventricular block and delta wave, the prevalence rates were 4.0, 7.0, 4.6, 2.7, 2.4 and 1.3 per thousand respectively. Complete and incomplete left branch blocks, left anterior hemiblock, second degree antrioventricular block and short PR interval were rare in this survey.

Atrial myxoma: a review of clinical experience at Srinagarind Hospital.

Thirty-two intracardiac myxoma patients who underwent tumor excision in Srinagarind Hospital between January 1, 1983 and January 30, 1997 were retrospectively reviewed. Clinical presentations, diagnostic method, operative findings, and postoperative course were also analysed. There were 20 female and 12 male patients, age range 10 to 60 years (mean 37.9). Clinical presentations included congestive heart failure (56.2%), atypical chest pain (25.0%), syncope (18.9), and constitutional symptoms (9.3%). In six patients, there was clinical evidence of systemic embolism. One patient was essentially asymptomatic and incidentally detected during clinical check-up. Diagnosis was all made by two dimensional (2-D) echocardiographic study. There were 29 left atrial, 2 right atrial and 1 combined right atrial and right ventricular myxomas. There were 3 postoperative deaths, two due to septicemia and the other due to cerebral embolism. One patient developed postoperative severe mitral regurgitation and complete heart block needed mitral valve replacement and permanent pacemaker insertion. One patient developed localized seizure 6 years after resection and was suspected of brain metastasis. The other was found to have two high echogenic liver masses, 2 years after resection, suggestive of hepatic metastasis. Unfortunately, we could not obtain the histologic confirmation from any of those suspected lesions. Because of the non-specific and various manifestations of atrial myxoma, a high index of suspicion is needed. The diagnostic method of choice is 2D-echocardiography. Clinical follow-up for at least 10 years may be needed to rule out recurrence or metastasis.