Digoxin toxicity in Thai medical patients: clinical manifestations and an appropriate diagnostic serum level

This study considers the clinical manifestations and risk factors of digoxin toxicity and establishes an appropriate cut-off serum level for the diagnosis of toxicity. A retrospectivestudy of 125 hospitalized patients whose serum digoxin was assayed in 1998 was conducted. Of the 125 subjects, 42 (33.6%) were classified as having definite digoxin toxicity, 9 (7.2%) were classified as having probable digoxin toxicity, and 74 (59.2%) were classified as non-toxicated. Of the patients with definite digoxin toxicity, 24 (57.1%) had cardiac manifestations, seven (16.7%) had non-cardiac manifestations, and 11 had manifestations of both types. The commonest manifestation was atrial fibrillation with block. Average daily doses of digoxin in the patients with definite digoxin toxicity and those without intoxication varied from 0.125 to 0.5 ng/ml. There was no significant statistical difference in digoxin dosage between those with and those without digoxin toxicity. Seven univariate factors of digoxin toxicity were examined: logistic regression analysis showed that, serum BUN and serum chloride were independent associated factors of digoxin toxicity: the finding suggests that renal impairment and volume contraction are strong determinants of digoxin toxicity. Mean (SD) serum digoxin levels among the patients with and without toxicity were 2.28 (1.3) and 1.05 (0.6) ng/ml respectively (p = 0.000). The best cut-off level determined by Receiver Operating Characteristic (ROC) analysis was 1.97 ng/ml. However, a low sensitivity and a high specificity make serum digoxin levels a diagnostic rather than a screening tool. The manifestations of digoxin toxicity among Thai inpatients are no different from those of other populations. The best cut-off level of serum digoxin for the diagnosis of toxicity is 2 ng/ml.     

Bundle-branch block in middle-aged men: risk of complications and death over 28 years. The Primary Prevention Study in G?teborg, Sweden.

AIMS: To investigate the long-term fate of men with bundle-branch block (BBB) from a general population sample. METHODS AND RESULTS: Data were derived from 7392 men without a history of myocardial infarction or stroke, born between 1915 and 1925 and investigated between 1970 and 1973. All participants were followed from the date of their baseline examination until 1998. We identified 70 men with right-BBB and 46 men with left-BBB at baseline. In men with right-BBB, there was no increased risk of myocardial infarction, coronary death, heart failure, or all-cause mortality during follow-up. The multiple-adjusted hazard ratio for progression to high-degree atrioventricular block was 3.64 (99% confidence interval 0.79-16.72). In men with left-BBB, the hazard ratio for high-degree atrioventricular block was 12.89 (4.13-40.24). However, hazard ratio for all-cause mortality was 1.85 (1.15-2.97) when compared with men without BBB, mostly due to outside hospital coronary deaths, whose hazard ratio was 4.22 (1.90-9.34). CONCLUSION: The presence of BBB was strongly associated with future high-degree atrioventricular block that was more pronounced for left-BBB. Men with left-BBB have a substantially increased risk of coronary death, mainly due to sudden death outside the hospital setting.     

The clinical significance of plasma glycoside concentrations in patients with cardiac pacemakers (author's transl)

308 digitalized out-patients with artificial cardiac pacemakers were explored for signs of glycoside toxicity with simultaneous determination of digoxin plasma levels 12 hours after the last dose. The incidence of different side effects commonly attributed to overdigitalization did not allow prediction of toxic plasma levels. 55% of all glycoside levels were within the therapeutic range, 34% were below 0.7 ng/ml and only 11% above 2.0 ng/ml. With the most commonly prescribed maintenance doses of the glycosides used (digoxin 0.5 mg, beta-acetyldigoxin 0.4 mg, beta-methyldigoxin 0.2 mg, lanatosid C 1.0 mg) therapeutic plasma levels were reached regularly in 60-65% of the patients. A significant correlation existed between plasma glycoside concentrations and renal function as well as age, but glycoside concentrations could not be correlated with the age of the patients. There were no indications for interactions of the different glycosides prescribed with diuretics or oral antidiabetics.     

Safety of transvenous temporary cardiac pacing in patients with accidental digoxin overdose and symptomatic bradycardia

BACKGROUND: Patients with digoxin intoxication may need transvenous temporary cardiac pacing (TCP) when symptomatic bradyarrhythmias are present. However, it has been reported that TCP might be associated with fatal arrhythmias in patients with acute digitalis intoxication caused by attempted suicide. The aim of this study was to assess the safety of TCP in patients with accidental digoxin-related symptomatic bradyarrhythmias. MATERIALS AND METHODS: Seventy patients (30 men; age 74 +/- 12 years) were enrolled in this retrospective study. Patients were divided into two groups: group 1 with TCP and group 2 without TCP. A digoxin overdose was defined as a serum digoxin level higher than 2.0 ng/ml combined with the presence of digoxin-related symptoms. Detailed clinical characteristics were reviewed on the basis of the medical records. RESULTS: Group 1 included 24 patients (34.3%, 10 men). The rhythms prior to pacemaker insertion in group 1 included sinus arrest with junctional bradyarrhythmias (n = 9), atrial fibrillation with a slow ventricular rate (n = 11), and high-degree atrioventricular block (n = 4). The mean duration of pacemaker implantation was 5.8 +/- 2.9 days (2-12 days). There was no major arrhythmic event or mortality after TCP in group 1. Two patients in group 2 (4%) died of ventricular tachyarrhythmias. Group 1 had a higher level of blood urea nitrogen (45.1 +/- 26.0 vs. 33.4 +/- 19.3 mg/dl), of left ventricular ejection fraction (68 vs. 56%), and of digoxin (4.4 +/- 2.1 vs. 3.4 +/- 1.3 ng/ml) but a lower serum calcium level (8.7 +/- 0.6 vs. 9.1 +/- 0.8 mg/dl). CONCLUSION: TCP was safe for patients with a digoxin overdose complicated by symptomatic bradycardia and should be recommended in such situations. However, this conclusion does not apply to acute digoxin intoxication as a result of attempted suicide.     

Recognition and management of digitalis toxicity.

The most important step in the management of toxicity due to any of the cardiac glycosides is its recognition. Despite the development of an accurate clinical assay for serum levels of digoxin greater than 20 years ago, digitalis toxicity remains common and difficult to confirm, even if suspected, due primarily to 2 factors. First, the signs and symptoms of digitalis toxicity, most commonly an abnormal electrocardiogram showing ventricular or atrial arrhythmias, with or without some degree of concurrent atrioventricular block, often also occur in patients with congestive heart failure (CHF) and underlying coronary atherosclerosis who are not receiving a cardiac glycoside. Second, due to digoxin's narrow therapeutic ratio, the marked degree of variability in the sensitivity of individual patients to its toxic effects, and the common problem of obtaining blood samples inappropriately during the early distribution phase following dosing, a serum digoxin concentration often does not serve as a reliable indicator of toxicity. Despite these difficulties in diagnosis, the management of digoxin toxicity has been made much more effective with the widespread availability of F(ab) fragments of anti-digoxin antibodies. This drug provides the clinician with a rapidly acting, safe antidote for all commonly used digitalis preparations. Conventional therapy for digoxin toxicity remains the maintenance of serum potassium levels greater than or equal to 4 mEq/liter, reversal of decompensated CHF or overt myocardial ischemia, attention to serum magnesium levels and the patient's acid-base status, appropriate antiarrhythmics in the event of ventricular arrhythmias, and a temporary pacemaker for high-grade atrioventricular block. Nevertheless, the high specificity and documented safety of the antibody preparation provides a needed safety net for the continuing use of cardiac glycosides as first-line inotropic agents in the modern therapy of chronic CHF.     

Ischemic blocks during early phase of anterior myocardial infarction: correlation with ST-segment shift

Of 760 consecutive cases with anterior acute myocardial infarction (AMI), 55 developed acute bundle-branch block (BBB), fascicular block, or high-degree atrioventricular block during the hyperacute ECG stage of AMI. According to the direction of the ST segment during the acute ischemic episode, patients were divided into two groups. Group A consisted of 32 patients who developed BBB during ST-segment elevation, positive T wave, and absent or minimal Q wave. Group B consisted of 23 patients who developed BBB during ST-segment depression and evolved into anterior AMI. Group A was characterized by a higher incidence of right BBB and left anterior hemiblock [91% vs. 26% and 56% vs. 13%, respectively (p less than 0.005)]. Group B was characterized by a higher incidence of left BBB and left posterior hemiblock [57% vs. 9% and 26% vs. 12%, respectively (p less than 0.001)]. The BBB was transient (disappearing within hours to one day) in 14 patients in Group A and in 5 patients in Group B. The incidence of progression to high-degree atrioventricular block was almost equal in the two groups (25% and 26%). The mortality rate was very high in both groups, but higher in Group B [74% vs. 59% (p = NS)] especially in those with LBBB (85%). Most patients died on the day of occurrence of BBB [Group A, 50% vs. Group B, 70% (p = NS)]. The causes of death in both groups were cardiogenic shock and/or electromechanical dissociation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Hemofiltration in digoxin overdose

We used hemofiltration to treat a patient with digoxin overdose complicated by refractory hyperkalemia, congestive heart failure, chronic renal failure, and complete atrioventricular heart block. Hemofiltration was associated with a progressive fall in plasma digoxin level and potassium level. This was accompanied by resolution of the heart failure and complete heart block. Hemofiltration appears to provide a therapeutic alternative in digoxin overdose.     

Recrudescent Digoxin Toxicity Treated with Plasma Exchange: A Case Report and Review of Literature

A 53-year-old woman presented with digitalis toxicity caused by acute overdose that manifested as atrial tachycardia with block, sinus pauses, and competing AV junctional rhythm with atrial fibrillation. Patient admitted to overdosing with digoxin 15?C20?h before presentation with intent to commit suicide. Serum digoxin level was 35.6?ng/ml and renal function was normal. Patient was treated with 1,040?mg of digoxin-specific antibody Fab fragment with prompt resolution of arrhythmias and restoration of sinus rhythm. Four hours after digoxin antibody administration, serum digoxin level declined to 0.2?ng/ml. Eighteen hours after treatment with Fab fragment, patient developed premature ventricular complexes, atrial tachycardia with and without atrioventricular block, and non-sustained ventricular tachycardia followed by ventricular fibrillation from which she was successfully resuscitated. Electrocardiogram showed no evidence of acute myocardial infarction, and emergent coronary angiogram did not reveal significant coronary artery disease. Repeat digoxin level was 20.4?ng/ml. A diagnosis of recrudescent digoxin toxicity was made and the patient was treated with one session of plasma exchange with resolution of arrhythmias. Immediately after plasma exchange, digoxin level decreased to 10.4?ng/ml, and after 10?h, the level further decreased to 6.6?ng/ml. The following day, digoxin level had decreased to 2.9?ng/ml. Our experience with this case would suggest that plasma exchange should be considered as a treatment modality for recrudescent digoxin toxicity.     

桥接起搏器在经导管主动脉瓣置换术后合并高度房室传导阻滞中应用的安全性及可行性分析

目的探讨对经导管主动脉瓣置换术(TAVR)后出现高度房室传导阻滞患者植入桥接起搏器的安全性及可行性。方法纳入2019年8月1日至2020年8月1日在郑州大学第一附属医院接受TAVR治疗后出现高度房室传导阻滞而植入桥接起搏器的主动脉瓣重度狭窄患者10例。观察其术后30 d每天心电图变化、血流动力学改善情况及相关并发症发生情况,并评估应用桥接起搏器的安全性和可行性。结果10例患者术后2 d内均未恢复传导,均给予植入桥接起搏器。所有患者均无起搏器并发症发生。3例患者心脏传导功能分别在TAVR后第8天、第21天、第7天恢复而未植入永久起搏器,其余7例在TAVR后30 d均未恢复心脏传导功能,给予植入永久起搏器。术后1个月随访显示临床症状及心功能改善,超声心动图提示血流动力学改善。结论TAVR后合并高度房室传导阻滞在术后2 d未恢复心脏传导功能患者植入桥接起搏器是安全及可行的,降低了起搏器植入率且不影响其心功能恢复。     

Impact of radiofrequency catheter ablation of accessory pathways on the frequency of atrial fibrillation during long-term follow-up; high recurrence rate of atrial fibrillation in patients older than 50 years of age.

AIMS: Atrial fibrillation represents a frequent and potentially life-threatening arrhythmia in patients with accessory atrioventricular pathways. Radiofrequency ablation has become the curative treatment of first choice for these patients. Investigations after successful surgical pathway dissection reported an almost complete elimination of paroxysmal atrial fibrillation. However, there are only a few reports which include a small number of patients undergoing radiofrequency ablation. The purpose of this study was to examine whether successful radiofrequency ablation of accessory pathways prevents the occurrence of paroxysmal atrial fibrillation, and to identify possible predictors of atrial fibrillation recurrence. METHODS AND RESULTS: A total of 116 consecutive patients (mean age 42+/-15 years) with manifest or concealed accessory pathways and documented paroxysmal atrial fibrillation underwent radiofrequency catheter ablation. The patients were reexamined at 6 and 12 months. Long-term follow-up information was obtained by questionnaire and/or by consulting the referring physician. Pathway conduction was abolished in 101 cases (87%). Late follow-up information was obtained from 91 of these 101 patients (90%) with successful ablation with a mean follow-up duration of 23.9+/-12.3 months. During follow-up, 25 of 91 patients (27%) experienced arrhythmias. Recurrent episodes of atrial fibrillation were observed in 18 of these 25 cases (i.e. 20% of the 91 patients). Differences between patients with and without recurrences of atrial fibrillation were examined for age, sex, associated cardiac disease, presence of multiple pathways, pathway location, atrial fibrillation inducibility during the procedure and cycle length of the atrioventricular reentrant tachycardia. Only older age was a significant independent predictor of atrial fibrillation recurrence (P=0.02). Eleven of 31 patients (35%) older than 50 years of age had atrial fibrillation recurrences during follow-up compared to seven of 60 patients (12%) under age 50. The recurrence rate of atrial fibrillation was even higher in patients older than 60 years (6 of 11 patients, i.e. 55%). In comparison, the occurrence rate of atrial fibrillation during follow-up in a control group of 100 consecutive patients with successful accessory pathway ablation, who did not have evidence of paroxysmal atrial fibrillation prior to ablation, was 4% and, thus, significantly lower than in the study group of the 91 patients (P=0.001). CONCLUSIONS: The recurrence rate of paroxysmal atrial fibrillation after successful radiofrequency ablation of accessory pathways shows an age-related increase, being low in patients younger than 50 years of age (12%) and high in the older patients: 35% in patients older than 50 years and 55% in patients older than 60. These results have significant therapeutic implications concerning the decisions on pharmacological therapy after successful ablation in patients older than 50 years. Furthermore, these data will help physicians advise older patients properly about their risk of recurrence of atrial fibrillation after ablation.     

Interpretation of excessive serum concentrations of digoxin in children

Between January 1981 and April 1984, excessive serum concentrations of digoxin (5 ng/ml or higher) were recorded in 47 children, aged 2 days to 16 years. In 10 patients, the high concentrations were measured 9.25 to 48 hours after death and were significantly higher than antemortem levels in all cases (8.3 +/- 2.4 (+/- standard deviation) postmortem vs 3.3 +/- 1.5 antemortem, less than 0.0001). In 15 patients (40.5% of the living patients) serum concentrations of 5 ng/ml or higher reflected sampling errors; drug levels were monitored too closely to the administration of a dose. None of these children had toxic manifestations of digoxin. In 10 patients, the excessive concentrations were associated with renal failure and a prolonged elimination half-life (T1/2) of digoxin; in 3 of these patients, there were signs of digoxin toxicity. Six cases were caused by digoxin overdose (accidental ingestions, pharmacy error and a suicide attempt). In 6 additional cases, the existence of an endogenous digoxin-like substance (EDLS) was shown to contribute to the excessive levels of the drug. One case could be attributed to digoxin-amiodarone interaction. In 10 of 37 living patients, digoxin toxicity was diagnosed. After excluding the 15 sampling errors and 6 cases with EDLS, this represents 63% of the cases. There was a good correlation between digoxin elimination T1/2 and serum creatine concentrations (r = 0.71, p less than 0.01). The above observations suggest that excessive serum concentrations of digoxin may not necessarily reflect potentially toxic levels.(ABSTRACT TRUNCATED AT 250 WORDS)     

Prevalence of intraventricular block in the general population: the Framingham Study

QRS intervals in the ECGs of members of the Framingham Heart Study cohort and offspring were measured to provide an estimate of the prevalence of intraventricular block in the general population. Intervals of greater than or equal to 0.09 second appear in men twice as commonly as in women, are rare before age 50 to 60, and shift from a predominance of right bundle branch block in the young to an indeterminate pattern in the elderly. Complete intraventricular block (QRS interval greater than or equal to 0.12 second) is seen in 11% of elderly men and 5% of elderly women. Aside from age and sex, logistic regression indicates strong associations with concurrent manifestations of coronary heart disease, congestive heart failure, and atrioventricular block, as well as hypertension, left ventricular hypertrophy, and ventricular extrasystoles. Among those subjects free of clinical coronary disease and congestive heart failure, associations between QRS interval and age, sex, atrioventricular block, and ECG left ventricular hypertrophy remain significant by multivariate analysis. Whether people with prolonged QRS intervals need special monitoring or attention cannot be told from these data.     

A case of congenitally corrected transposition of the great arteries with rare but life-threatening ventricular tachycardia and a coincidental single coronary ostium

Congenitally corrected transposition of the great vessels (CCTGA) is a rare congenital heart defect. Patients with CCTGA have the anatomical right ventricle as their systemic pumping chamber, with ventricular dysfunction and congestive heart failure (CHF) being relatively common in older adults. The most common presenting feature is bradycardia due to high-degree atrioventricular (AV) blocks. Patients with CCTGA are increasingly subject to CHF with advancing age; this complication is extremely common by the fourth decade. The majority of patients have an inverted coronary arterial pattern.1 We report a case of a patient with CCTGA who presented with rare but life-threatening ventricular tachycardia (VT) leading to syncope, with preserved systemic ventricular function. Coincidentally, the patient also had a single coronary ostium.     

Diminished cardiac hypertrophy and muscle performance in older compared with younger adult rats with chronic atrioventricular block

The combined effect of advancing age and hemodynamic overload on cardiac muscle function has received little attention. In male, Sprague-Dawley rats, we studied the interaction of chronic atrioventricular heart block induced by transvenous electrocautery for 4-12 months (mean, 7 months) and age at study (12, 19 +/- 0.7, and 24 +/- 0.2 months) on cardiac hypertrophy and muscle function compared with age-matched, sham-operated controls. Hypertrophy was determined by the ratio of heart weight to tibial length. Muscle function was first determined from the mechanical variables of the isometric contraction of an excised, thin, left ventricular trabecular muscle bathed at 29 degrees C under a variety of calcium concentrations and stimulation patterns. Then, in the same muscles after disruption of membranes with Triton X-100, the force-pCa curve of the myofibrils was obtained. No hypertrophy occurred with aging in the control group, but alteration in hypertrophy with age occurred in the block group such that the youngest animals with block had the most hypertrophy (170%) and the oldest animals with block the least hypertrophy (120%). The tension developed by cardiac muscle and the duration of the isometric contraction were not affected by age in the control group but were significantly affected by age in the block group. The young animals with block had a markedly prolonged contraction duration and almost twice the developed tension compared with the older animals with block or with controls. The age-related difference in muscle contraction duration in the block group was associated with, and may have only been secondary to, the age-related difference in the extent of cardiac hypertrophy. For developed tension, the age-related difference in the block group could not be explained by differences in the extent of cardiac hypertrophy. Rather, this difference was attributable to both an increased myofibrillar force-generating capacity in the young block and to an impairment in excitation-contraction coupling in the old block. The results show that during long-term block, age exerted not only a significant effect on the extent of cardiac hypertrophy but also an independent effect on the developed tension of cardiac muscle.     

Life-Threatening Cryoglobulinemic Patients With Hepatitis C: Clinical Description and Outcome of 279 Patients

Cryoglobulinemia is characterized by a wide range of causes, symptoms, and outcomes. Hepatitis C virus (HCV) infection is detected in 30%–100% of patients with cryoglobulins. Although more than half the patients with cryoglobulinemic vasculitis present a relatively benign clinical course, some may present with potentially life-threatening situations. We conducted the current study to analyze the clinical characteristics and outcomes of HCV patients presenting with life-threatening cryoglobulinemic vasculitis. We evaluated 181 admissions from 89 HCV patients diagnosed with cryoglobulinemic vasculitis consecutively admitted to our department between 1995 and 2010. In addition, we performed a systematic analysis of cases reported to date through a MEDLINE search.The following organ involvements were considered to be potentially life-threatening in HCV patients with cryoglobulinemic vasculitis: cryoglobulinemic, biopsy-proven glomerulonephritis presenting with renal failure; gastrointestinal vasculitis; pulmonary hemorrhage; central nervous system (CNS) involvement; and myocardial involvement. A total of 279 patients (30 from our department and 249 from the literature search) fulfilled the inclusion criteria: 205 presented with renal failure, 45 with gastrointestinal vasculitis, 38 with CNS involvement, 18 with pulmonary hemorrhage, and 3 with myocardial involvement; 30 patients presented with more than 1 life-threatening cryoglobulinemic manifestation. There were 146 (52%) women and 133 (48%) men, with a mean age at diagnosis of cryoglobulinemia of 54 years (range, 25–87 yr) and a mean age at life-threatening involvement of 55 years (range, 25–87 yr). In 232 (83%) patients, life-threatening involvement was the first clinical manifestation of cryoglobulinemia. Severe involvement appeared a mean of 1.2 years (range, 1–11 yr) after the diagnosis of cryoglobulinemic vasculitis. Patients were followed for a mean of 14 months (range, 3–120 mo) after the diagnosis of life-threatening cryoglobulinemia. Sixty-three patients (22%) died. The main cause of death was sepsis (42%) in patients with glomerulonephritis, and cryoglobulinemic vasculitis itself in patients with gastrointestinal, pulmonary, and CNS involvement (60%, 57%, and 62%, respectively). In conclusion, HCV-related cryoglobulinemia may result in progressive (renal involvement) or acute (pulmonary hemorrhage, gastrointestinal ischemia, CNS involvement) life-threatening organ damage. The mortality rate of these manifestations ranges between 20% and 80%. Unfortunately, this may be the first cryoglobulinemic involvement in almost two-thirds of cases, highlighting the complex management and very elevated mortality of these cases.     

Cardiac arrhythmias in the elderly: clinical aspects

Abnormal cardiac rhythms appear more normal frequently in the elderly population. Studies confirm that the incidence of serious or life-threatening arrhythmias, including Mobitz type II atrioventricular block and ventricular tachycardia, increases the incidence of cardiac disease in this population group. As age progresses, the hemodynamic manifestations are more symptomatic and require specific therapy, including cardiac pacemakers and antiarrhythmic agents.     

Metabolic, anthropometric, and nutritional factors as predictors of circulating insulin-like growth factor binding protein-1 levels in middle-aged and elderly men

Circulating IGF binding protein (IGFBP)-1 levels have been associated with insulin sensitivity, the metabolic syndrome, several cardiovascular risk factors, and possibly with cancer. We examined long-term nutrient intake and metabolic and anthropometric factors in relation to IGFBP-1 levels in 226 men, 42-76 yr old, who completed 14 24-h diet recall interviews. Spearman rank correlation coefficients were calculated. Serum IGFBP-1 levels were significantly inversely correlated with insulin, homeostasis model assessment-insulin resistance, and IGF-I and positively correlated with age. Furthermore, IGFBP-1 was inversely correlated with anthropometric measures reflecting obesity, somewhat stronger in middle-aged (<65 yr) than in older men. Serum IGFBP-1 increased with higher energy and carbohydrate intake but only in the younger age group. The difference in mean IGFBP-1 levels comparing men in the top quartile of carbohydrate intake with those in the bottom quartile was 45% in men of age 42-54 yr (P = 0.01). Insulin, body mass index, and carbohydrate intake together explained 39% of the variability in IGFBP-1 levels in men 42-54 yr of age, 27% in men 55-64 yr, and 6% in men 65 or more years old. Our data suggest that metabolic, anthropometric, and nutritional factors are important determinants of IGFBP-1 levels in healthy men.     

Sarcopenia and its associated factors in Iranian older individuals: Results of SARIR study

BackgroundSarcopenia, an age- related loss of muscle mass, is a significant associating factor for functional impairment among older adults. The aim of this study was to investigate the prevalence of and associated factors for sarcopenia and severe sarcopenia among older adults in Iran.MethodsA total of 300 individuals aged over 55 years were randomly selected from the 6th district of Tehran, Iran, in 2011. Sarcopenia was defined according to the European Working Group on Sarcopenia in Older People (EWGSOP) algorithm. The skeletal muscle mass was assessed using DXA. Muscle strength and muscle performance were assessed according to hand grip strength and 4-m usual walking gait speed test. A logistic regression analysis was performed.ResultsThe prevalence values of presarcopenia, sarcopenia, and severe sarcopenia were 52.7%, 20.7%, and 6%, in men and 25.3%, 15.3%, and 5.3% in women, respectively. The prevalence of sarcopenia was higher in men older than 75 years than women in the same age range (36.7% versus 20%, respectively). Using multiple logistic regression models, age, sex, smoking, and body mass index (BMI) were independently associated with different stages of sarcopenia.ConclusionsThe prevalence of sarcopenia is high in Iranian older adults. The older age, male sex, smoking and lower BMI were independently associated with presarcopenia, sarcopenia and severe sarcopenia.     

Use of digoxin in patients with paroxysmal supraventricular tachycardia

The effectiveness and electrophysiologic mechanisms of antiarrhythmic effect of digoxin were examined in 27 patients with paroxysmal atrioventricular nodal reciprocal tachycardia (PAVNRT) and supraventricular tachycardia (SVT) due to latent complementary conductive pathways, i. e. latent Wolff-Parkinson-White (WPW) syndrome. To assess antiarrhythmic action of digoxin, transesophageal pacing and plasma digoxin radioimmonoassays were used. Preventive antiarrhythmic efficiency of digoxin was 53% in PAVNRT patients, and 25% in SVT patients with latent WPW syndrome. Antegrade atrioventricular conduction block seems to be the mechanism of oral digoxin preventive effect. There was no relationship between antiarrhythmic efficiency of digoxin and its plasma level.     

Acute toxic effects of sustained-release verapamil in chronic renal failure.

Four hypertensive patients with chronic renal insufficiency or end-stage renal disease who were treated with sustained-release verapamil hydrochloride subsequently developed acute toxic effects. All four patients developed varying degrees of atrioventricular heart block, hypotension, hyperkalemia, metabolic acidosis, and hepatic dysfunction. Supportive treatment consisted of intravenous catecholamines, sodium polystyrene sulfonate, and dialysis, and all patients recovered completely without any residual hepatic or cardiac disease. Patients with renal impairment who are treated with sustained-release verapamil may accumulate verapamil or its metabolites and develop toxic side effects. We conclude that sustained-release verapamil should be used with caution in this patient population and that patients should be closely monitored for adverse cardiovascular, metabolic, and hepatic side effects.