Endothelin and cardiac arrhythmias: do endothelin antagonists have a therapeutic potential as antiarrhythmic drugs?

Endothelin-1 (ET-1), the predominant isoform of the ET peptide family and a potent vasoconstrictor, has been shown to aggravate ischemia-induced ventricular arrhythmias. However, there is also evidence that ET-1 may have a direct arrhythmogenic action that is not solely attributable to myocardial ischemia. Proposed mechanisms for the arrhythmogenic effects of ET-1 are prolongation or increased dispersion of monophasic action potential duration, QT prolongation, development of early afterdepolarizations, acidosis, and augmentation of cellular injury. As for an ionic basis for the observed electrophysiologic effects, ET-induced Ca2+ release from intracellular stores, generation of inositol triphosphate, inhibition of delayed rectifier K+ current, and stimulation of the Na+/H+ exchanger may be involved. Recently, some studies have shown that ET receptor antagonists, which promise to be powerful tools in cardiovascular medicine, may also demonstrate antiarrhythmic properties. This review describes the current state of knowledge on the interactions between the ET system and cardiac arrhythmias, and discusses the therapeutic potential of ET antagonists as antiarrhythmic drug

In vivo heating of pacemaker leads during magnetic resonance imaging

Aims Magnetic resonance imaging (MRI) is well established as an important diagnostic tool in medicine. However, the presence of a cardiac pacemaker is usually regarded as a contraindication for MRI due to safety reasons. In this study, heating effects at the myocardium-pacemaker lead tip interface have been investigated in a chronic animal model during MRI at 1.5 Tesla. Methods and results Pacemaker leads with additional thermocouple wires as temperature sensors were implanted in nine animals. Temperature increases of up to 20°C were measured during MRI of the heart. Significant impedance and minor stimulation threshold changes could be seen. However, pathology and histology could not clearly demonstrate heat-induced damage. Conclusions MRI may produce considerable heating at the lead tip. Changes of pacing parameters due to MRI could be seen in chronic experiments. Potential risk of tissue damage cannot be excluded even though no reproducible alterations at the histological level could be foun

Sinus node disease and arrhythmias in the long-term follow-up of former professional cyclists

Aims Significant brady- and tachyarrhythmias may occur in active endurance athletes. It is controversial whether these arrhythmias do persist after cessation of competitive endurance training. Methods and results Among all 134 former Swiss professional cyclists [hereafter, former athletes (FAs)] participating at least once in the professional bicycle race Tour de Suisse in 1955-1975, 62 (46%) were recruited for the study. The control group consisted of 62 male golfers matched for age, weight, hypertension, and cardiac medication. All participants were screened with history, clinical and echocardiographic examination, ECG, and 24 h ECG. The time for the last bicycle race of FAs was 38 ± 6 years. The mean age at examination was 66 ± 6 years in controls and 66 ± 7 years in FAs (P = 0.47). The percentage of study participants with >4 h current cardiovascular training per week was identical. QRS duration (102 ± 20 vs. 95 ± 13 ms, P = 0.03) and corrected QTc interval (416 ± 27 vs. 404 ± 18, P = 0.004) were longer in FAs. There was no significant difference in the number of isolated atrial or ventricular premature complexes, or supraventricular tachycardias in the 24 h ECG; however, ventricular tachycardias tended to occur more often in FAs than in controls (15 vs. 3%, P = 0.05). The average heart rate was lower in FAs (66 ± 9 vs. 70 ± 8 b.p.m.) (P = 0.004). Paroxysmal or persistent atrial fibrillation or flutter was reported more often in FAs (P = 0.028). Sinus node disease (SND), defined as bradycardia of 2.5 s (6 vs. 0%), was more common in FA (16%) than in controls (2%, P = 0.006). Observed survival of all FAs was not different from the expected. Conclusions Among FAs, SND occurred significantly more often compared with age-matched controls, and there is trend towards more frequent ventricular tachycardias. Further studies have to evaluate prevention of arrhythmias with extreme endurance training, the necessity of regular follow-up of heart rhythm, and management of arrhythmias in former competitive endurance athlete

Electronic Voting to Improve Morbidity and Mortality Conferences.

BACKGROUND It is of major importance in clinical surgery to identify potential patterns and specific causes of complications. Therefore, morbidity and mortality meetings (M&M) are widely used to discuss and evaluate deviations from expected outcomes in order to improve surgical practice. Moreover, M&M represent an important tool for continuous medical education. In this study, we introduced an electronic voting system to assess whether anonymity during M&M could limit potential biases due to hierarchical structures or opinion leaders. METHODS This study was conducted in the surgical department of a European tertiary care center. During the study period, electronic voting was applied in 412 M&M cases and compared with a baseline of 330 conventional M&M entries. In this interrupted time series, the educational quality and participant satisfaction of the M&M were assessed using surveys before and after the introduction of electronic voting. The surveys were refined using principle component analysis. In addition, the classification of the cause of the complication was recorded. RESULTS The introduction of electronic voting led to a significant increase in perceived educational quality from 2.63 to 3.36 (p < 0.01), and the overall participant satisfaction increased from 2.6 ± 0.9 to 3.7 ± 1.2 (p < 0.01) on a five-point Likert scale. The frequency of voting shifted from "patient's disease" (before 42.9, after 27.6%, p = 0.04) to "misadventure" (before 1.1, after 16.0%, p < 0.01). The voting frequencies for the causes attributed to "management" and "technical" remained constant. CONCLUSIONS An electronic voting system in M&M meetings increases perceived educational quality and participant satisfaction

The advantages of extended subplatysmal dissection in thyroid surgery-the "mobile window" technique.

PURPOSE Minimal access thyroidectomy, using various techniques, is widely known, but respective data on thyroidectomy for thyroid cancer with lymphadenectomy is scarce. The present study aims to evaluate the feasability of extended subplatysmal dissection in combination with a small incision ("mobile window" technique). METHODS A retrospective study was performed analysing data from 93 patients. All patients suffered from thyroid carcinoma and underwent (total) thyroidectomy, bilateral cervico-central (levels VI and VII) and functional lateral neck dissection (levels II to V) on the side of the malignancy. In group A, consisting of 47 patients, the operation was performed by a traditional Kocher incision (minimal range 6-7 cm), in 46 patients (group B) a mini-incision (≤4 cm) was made. Intra- and postoperative morbidity as well as oncological accuracy were assessed. RESULTS There was no significant difference between the two groups comparing postoperative pathological diagnosis, intra- and postoperative complications and the number of removed lymph nodes. However, operating time was slightly longer in group A and thyroid weight was heavier in group B. CONCLUSIONS Extended subplatymsal dissection allows thyroidectomy and even lateral lymphadenectomy for thyroid carcinoma via "mobile" mini-incision. The procedure is safe, of equivalent oncological accuracy compared to traditional incision and the cosmetic results are excellent

In vivo heating of pacemaker leads during magnetic resonance imaging

Aims Magnetic resonance imaging (MRI) is well established as an important diagnostic tool in medicine. However, the presence of a cardiac pacemaker is usually regarded as a contraindication for MRI due to safety reasons. In this study, heating effects at the myocardium-pacemaker lead tip interface have been investigated in a chronic animal model during MRI at 1.5 Tesla. Methods and results Pacemaker leads with additional thermocouple wires as temperature sensors were implanted in nine animals. Temperature increases of up to 20°C were measured during MRI of the heart. Significant impedance and minor stimulation threshold changes could be seen. However, pathology and histology could not clearly demonstrate heat-induced damage. Conclusions MRI may produce considerable heating at the lead tip. Changes of pacing parameters due to MRI could be seen in chronic experiments. Potential risk of tissue damage cannot be excluded even though no reproducible alterations at the histological level could be foun