Cardioprotective effect of fasting on ischemia reperfused rat heart after diazepam administration

Fasting and calorie restriction have some Cardioprotective effects. In view of the effect of fasting on peripheral benzodiazepine receptors and widespread administration of benzodiazepines in medicine, the present study was designed to evaluate whether fasting may affect myocardial vulnerability to cardiac ischemia-reperfusion [I/R] following repeated diazepam administration. Rats were divided into six groups of 8 or 10 animals. Groups I and II were controls which received intra peritoneal injection of normal saline solution for 5 days. Also, Control II underwent fasting on 5th day of experiment. Four test groups received intra peritoneal injection of diazepam for 5 days [groups I and II Img/kg; groups III and IV 5 mg/kg]. Also, test groups II and IV fasted on 5th day of experiment. The Langendorff isolated hearts were subjected to 25 minutes ischemia and 25 minutes reperfusion. Cardiac parameters including - left ventricular developed pressure and rate pressure product were determined. Infarct size was measured by Triphenyltetrazolium staining. Recovery of the left ventricular developed pressure in diazepam groups were significantly lower than control I and II [P=0.049 and P=0.046 respectively]. But there was no significant difference among the controls and test group II, which fasted following diazepam administration. This showed the preservation of the cardiac performance in the fasting animals following administration of diazepam [1 mg/kg]. The results obtained showed the exacerbation of ischemia reperfusion injury in the presence of diazepam and demonstrated the protective effect of fasting which is probably due to modulation of the mitochondrial permeability transition pore

Pulmonary hypertension and predisposing factors in patients receiving hemodialysis

The aim of this study was to evaluate the frequency of unexplained pulmonary hypertension [PHT] among patients on hemodialysis at 2 centers and to evaluate possible predisposing factors. In this cross-sectional study, PHT was screened by Doppler echocardiography on the day after dialysis in 62 patients with end-stage renal disease receiving maintenance hemodialysis via arteriovenous access. Pulmonary hypertension was defined as a systolic pulmonary arterial pressure [PAP] higher than 35 mm Hg, and the systolic PAP was calculated using the modified Bernoulli equation. Clinical variables were compared between patients with and without PHT. A PAP higher than 35 mm Hg was found in 32 patients [49.3%] receiving hemodialysis, with a mean systolic PAP of 39.58 +/- 13.27 mm Hg. Blood hemoglobin level was significantly lower in the patients with PHT than those without PHT [9.8 +/- 1.97 g/dL versus 11.07 +/- 1.86 g/dL; P = .01]. In addition, serum levels of albumin was lower in these patients [3.38 +/- 0.32 g/dL versus 3.75 +/- 0.44 g/dL; P = .02]. This study demonstrates a surprisingly high prevalence of PHT among patients with end-stage renal disease receiving hemodialysis. We concluded that the best approach to this unrecognized complication that is associated with reduced survival is keeping it in mind and looking for it in the management of patients on dialysis

national survey of cardiac pacemakers and cardioverter defibrillators

Permanent pacemakers provide effective relief of symptoms and are life-saving in patients with symptomatic heart block. Implantable cardioverter defibrillators [ICD] are also increasingly recognized as life-saving tools in various groups of patients with malignant ventricular tachyarrhythmias. As part of the "world survey on pacemaker and ICD implantations ", A survey of all device implantations in Iran during the year 2001 was performed. Data was collected and cross-checked through three sources i.e. direct contact with implanting physicians, pacemaker companies and the governmental pacemaker distributing body. During the year studied, 1635 patients received permanent pacemakers. 88% were new implants at an estimated rate of 24 per million population. The mean age of patients was 65 years and 56.2% were male. 40 cardiologists and 19 surgeons implanted the pacemakers at 27 centers throughout the country. Complete heart block was consistently the most common indication at all centers [mean 56.1%], sick sinus syndrome being the next most common one [mean 20.8%]. 69% of the pacemakers were single chamber pacemakers. Transvenous insertion of bipolar steroid-eluting passive fixation leads was the predominant practice at most centers. A total of 60 ICDs were implanted at 7 centers by 9 cardiologists. 45% of ICD implants were dual chamber devices. The survey is the only one available right now and provides useful information about the prevailing pacemaker and defibrillator implantation practice in Iran. Future surveys would be facilitated if a standardized implant registry such as that used in Europe were established in this country