The influence of hemodynamic factors on left ventricular mass

We evaluated the relationship between the variability in the left ventricular mass index (LVMI) and different hemodynamic factors. LVMI was associated with blood pressure and, in one subgroup, strongly to arterial pulse wave velocity (PWV). High physical activity was connected to increased LVMI, and a combination of low stroke index (SI) and high heart rate (HR) to decreased LVMI.     

Conversion of paroxysmal atrial fibrillation to sinus rhythm by intravenous pirmenol

The acute effects of pirmenol on atrial fibrillation were investigated in 40 patients with paroxysm of atrial fibrillation. Patients were randomized to receive either pirmenol, 50 or 100 mg intravenously, or placebo. Patients with congestive heart failure or a history of sinus node disorder were excluded. Sinus rhythm was achieved in 12 of 20 patients in 2 to 16 minutes after pirmenol administration and in 3 of 20 patients in the control group within 1 hour. A nodal escape rhythm during sinus slowing was observed in 1 patient. No sinus arrest, atrioventricular conduction disturbance or hypotension appeared. Pirmenol has an antifibrillatory effect on the atria. Sinus rhythm is restored rapidly after intravenous administration. Treatment of atrial fibrillation of recent onset was well tolerated in patients accepted for the study.     

Usefulness of excitable gap and pattern of resetting in atrial flutter for determining reentry circuit location

Clinical and experimental data show that type I atrial flutter is due to a reentry mechanism with an excitable gap. To define the location of the reentry circuit of atrial flutter, width of excitable gap, poststimulation cycle and pattern of reset after premature stimulus were analyzed in 18 patients during atrial flutter at multiple atrial sites (high, lateral, posterior and septal right atrium, and coronary sinus). The pattern of reset was defined as flat or increasing whether the return cycle remained unchanged or prolonged with increasing prematurity. Shorter values of the excitable gap were found at the coronary sinus (33 +/- 8 ms) and high right atrium (30 +/- 10 ms) than at the posterior (43 +/- 9 ms) or septal right atrium (45 +/- 11 ms). Intermediate values (36 +/- 8 ms) were measured at the lateral right atrium. Poststimulation cycle, corrected for atrial flutter cycle length, was shorter in the posterior (6 +/- 7 ms) and septal right atrium (5 +/- 7 ms) than in the coronary sinus (35 +/- 9 ms), and the high (23 +/- 10 ms) and lateral right atrium (15 +/- 9 ms). A flat pattern of resetting occurred more frequently at the septal (18 of 18 patients) and posterior right atrium (15 of 18) than at the lateral (8 of 18) and high right atrium (2 of 17), and was never observed at the coronary sinus. Atrial flutter was successfully terminated by overdrive atrial pacing in 15 of 18 patients, and termination was more easily obtained from the septal and posterior right atrium.(ABSTRACT TRUNCATED AT 250 WORDS)     

Usefulness of the assessment of the appropriateness of left ventricular mass to detect left ventricular systolic and diastolic abnormalities in absence of echocardiographic left ventricular hypertrophy: the LIFE study

Conventional definitions of left ventricular (LV) hypertrophy do not account for interindividual differences in loading conditions. We may define LV mass as inappropriately high when exceeding 128% of theoretical values predicted by gender, height(2.7), and stroke work, which explain up to 82% of the variability of LV mass in normal reference subjects. In 652 participants in the Losartan Intervention For Endpoint reduction in hypertension study without clinically overt cardiovascular disease or diabetes, we investigated whether inappropriately high LV mass is associated with relevant LV abnormalities independent of traditional definition of LV hypertrophy (ie, LV mass index >116 g/m(2) in men and >104 g/m(2) in women). The study sample was divided into three groups: patients with inappropriately high LV mass but without LV hypertrophy were compared to patients with LV hypertrophy and to patients with appropriate LV mass and without LV hypertrophy. Patients with inappropriately high but nonhypertrophic LV mass had higher body mass index and relative wall thickness, and lower LV myocardial systolic function, than patients with appropriate LV mass or patients with LV hypertrophy. In multivariate analyses, inappropriately high LV mass was independently associated with lower myocardial systolic function independent of LV hypertrophy and other covariates. Inappropriately high LV mass was also associated with prolonged isovolumic relaxation time and lower mitral E/A ratio independent of covariates. In conclusion, inappropriately high LV mass was associated with relevant, often preclinical, manifestations of cardiac disease in the absence of traditionally defined echocardiographic LV hypertrophy and concentric geometry.     

Persistent ventricular tachycardia resulting in left ventricular dilatation treated with verapamil

A case with a verapamil-sensitive ventricular tachycardia showing right bundle branch block pattern and left axis deviation is described. Electrophysiological evaluation revealed features compatible with previous suggestions of posterior fascicular origin for this unique type of arrhythmia. In contrast to being paroxysmal, as is usually the case, the tachycardia was persistent and led to cardiac enlargement, which was completely reverted following successful treatment with verapamil.     

Association of left bundle branch block with left ventricular structure and function in hypertensive patients with left ventricular hypertrophy: the LIFE study

Electrocardiographic (ECG) left bundle branch block (LBBB) is associated with left ventricular hypertrophy (LVH), but its relation to left ventricular (LV) geometry and function in hypertensive patients with ECG LVH is unknown. Echocardiograms were performed in 933 patients (548 women, mean age 66+/-7 years) with essential hypertension and LVH by baseline ECG in the Losartan Intervention For Endpoint reduction in hypertension (LIFE) study. LBBB, defined by Minnesota code 7.1, was present in 47 patients and absent in 886 patients. Patients with and without LBBB were similar in age, gender, body mass index, blood pressure, prevalence of diabetes, and history of myocardial infarction. Despite similarly elevated mean LV mass (126+/-25 vs 124+/-26 g/m(2)) and relative wall thickness (0.41+/-0.07 vs 0.41+/-0.07, P=NS), patients with LBBB had lower LV fractional shortening (30+/-6 vs 34+/-6%), ejection fraction (56+/-10 vs 61+/-8%), midwall shortening (14+/-2 vs 16+/-2%), stress-corrected midwall shortening (90+/-13 vs 97+/-13%) (all P<0.001), and lower LV stroke index (38+/-7 vs 42+/-9 ml/m(2)) (P<0.05). Patients with LBBB also had reduced LV inferior wall and lower mitral E/A ratio (0.75+/-0.18 vs 0.87+/-0.38) (all P<0.05). The above univariate results were confirmed by multivariate analyses adjusted for gender, age, blood pressures, height, weight, body mass index, heart rate, and LV mass index. Among hypertensive patients at high risk because of ECG LVH, the presence of LBBB identifies individuals with worse global and regional LV systolic function and impaired LV relaxation without more severe LVH by echocardiography.     

Unimodal distribution of bronchial hyperresponsiveness to methacholine in asthmatic patients.

Distribution of bronchial hyperresponsiveness to methacholine was assessed in 791 consecutive patients who were referred to the outpatient clinic of the pulmonary department due to asthmatic or persistent lower airway symptoms. Bronchial asthma was diagnosed in 319 patients. Clinical sensitivity of methacholine challenge for the disease was 89 percent and specificity, 76 percent. The degree of bronchial hyperresponsiveness in the entire group of asthmatic patients was unimodally log normal distributed. Of the 82 patients with allergic rhinitis without concurrent asthma, 27 percent had bronchial hyperresponsiveness, but of a markedly lesser degree than in the hyperresponsive asthmatic patients. In 49 patients with chronic bronchitis, 22 percent had hyperresponsiveness. The present data indicate that the degree of bronchial hyperresponsiveness in asthmatic patients is unimodally distributed, supporting the view that both genetic and environmental factors have an impact upon its development. Although the degree of bronchial hyperresponsiveness in asthma is more pronounced than in allergic rhinitis or in chronic bronchitis, a marked overlap exists.     

Sex-related difference in regression of left ventricular hypertrophy with antihypertensive treatment: the LIFE study

While left ventricular (LV) structure and function differ between hypertensive women and men, it remains unclear whether sex affects regression of LV hypertrophy with antihypertensive treatment. We analysed paired echocardiograms in 500 men and 347 women enrolled in the Losartan Intervention For Endpoint reduction in hypertension (LIFE) study at baseline and after 12 months of antihypertensive treatment with either losartan or atenolol. At enrollment, 177 women and 242 men were randomized to losartan-based treatment and 161 women and 247 men were randomized to atenolol-based treatment (sex difference=NS). After 12 months of antihypertensive treatment, blood pressure was lowered similarly in women (152/83 from 174/97 mmHg) and men (149/85 from 173/99 mmHg; both P<0.001, sex difference=NS), without significant change in body weight in either sex. Cardiac output and pulse pressure/stroke volume were equivalently reduced in both sexes (-0.2 vs -0.1 l/min and both -0.20 mmHg/ml/m(2), respectively; both P=NS). Absolute LV mass change after 12 months of antihypertensive treatment was greater in men than in women (-30 vs -24 g, P=0.01). However, after adjusting for baseline LV mass and randomized study treatment, LV mass reduction was greater in women than in men (-33 vs -23 g, P=0.001). LV mass regression was greater in women, by 8.0+/-2.8 g, after adjusting for baseline LV mass and randomized study treatment. After consideration of baseline LV mass and randomized study treatment, antihypertensive treatment regressed LV hypertrophy more in women. Further studies are needed to identify the mechanisms and prognostic implications of this sex-related difference.     

Contrast-induced nephropathy in patients undergoing primary angioplasty for acute myocardial infarction

OBJECTIVES: The aim of this research was to assess the incidence, clinical predictors, and outcome of contrast-induced nephropathy (CIN) after primary percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI). BACKGROUND: Contrast-induced nephropathy is associated with significant morbidity and mortality after PCI. Patients undergoing primary PCI may be at higher risk of CIN because of hemodynamic instability and unfeasibility of adequate prophylaxis. METHODS: In 208 consecutive AMI patients undergoing primary PCI, we measured serum creatinine concentration (Cr) at baseline and each day for the following three days. Contrast-induced nephropathy was defined as a rise in Cr >0.5 mg/dl. RESULTS: Overall, CIN occurred in 40 (19%) patients. Of the 160 patients with baseline Cr clearance >/=60 ml/min, only 21 (13%) developed CIN, whereas it occurred in 19 (40%) of those with Cr clearance <60 ml/min (p < 0.0001). In multivariate analysis, age >75 years (odds ratio [OR] 5.28, 95% confidence interval [CI] 1.98 to 14.05; p = 0.0009), anterior infarction (OR 2.17, 95% CI 0.88 to 5.34; p = 0.09), time-to-reperfusion >6 h (OR 2.51, 95% CI 1.01 to 6.16; p = 0.04), contrast agent volume >300 ml (OR 2.80, 95% CI 1.17 to 6.68; p = 0.02) and use of intraaortic balloon (OR 15.51, 95% CI 4.65 to 51.64; p < 0.0001) were independent correlates of CIN. Patients developing CIN had longer hospital stay (13 +/- 7 days vs. 8 +/- 3 days; p < 0.001), more complicated clinical course, and significantly higher mortality rate (31% vs. 0.6%; p < 0.001). CONCLUSIONS: Contrast-induced nephropathy frequently complicates primary PCI, even in patients with normal renal function. It is associated with higher in-hospital complication rate and mortality. Thus, preventive strategies are needed, particularly in high-risk patients.     

Low-level colonization and infection with ciprofloxacin-resistant gram-negative bacilli in a skilled nursing facility

Background: We report a 1-year surveillance study that evaluates colonization and infection with ciprofloxacin-resistant gram-negative bacilli (CR GNB) and the relation to quinolone use and other possible risk factors in a proprietary skilled nursing facility (SNF) with no history of outbreaks. Methods: Rectal swabs obtained quarterly were streaked on MacConkey agar with ciprofloxacin discs (5 μg) to screen for CR GNB and later were speciated and the antimicrobial susceptibilities were confirmed by standardized disc-diffusion tests. Results: The mean prevalence of CR GNB colonization was 2.6% (range 0.9% to 5.3%). The colonization frequency was higher in the last survey than it was in the first survey. CR GNB–colonized strains included Pseudomonas species (21%), but more than half were non-Pseudomonas enterics such as Acinetobacter baumannii (25%), Proteus mirabilis (17%), and Providencia stuartii (13%). None of the patients who had colonization with CR GNB had subsequent infections with the same species. Patients with colonization had more exposure to ciprofloxacin and they were more likely to have been recently admitted from an acute-care hospital and have decubitus ulcers. During the study period, of 336 patients surveyed, 98 (29%) patients developed suspected infections and cultures were done; the infection rate was 4.7 per 1000 patient days. Of these infected patients, 59 (60%) were infected by GNBs; the infection rate was 2.3 per 1000 patient days. Nineteen percent of the GNB infections were treated with a quinolone. (Overall, quinolones constituted about 17% of antibiotic usage in the SNF). Only 3 (5%) of the patients infected with GNB were infected with CR GNB, including Pseudomonas and Providenci a species. The CR GNB infections involved multiple sites, multiple organisms, and long length of stay in the SNF. Conclusions: The findings indicate that in this community SNF, a low frequency of colonization or infection with CR GNB existed. Whether continued moderate use of quinolones will lead to increasing levels of CR GNB will require further study. (AJIC Am J Infect Control 1998;26:552-7)