Karl Skarvan

Prevention of Supraventricular Tachyarrhythmias After Open Heart Operation by Low-Dose Sotalol: A Prospective, Double-Blind, Randomized, Placebo-Controlled Study☆

BACKGROUND The aim of this prospective, double-blind, placebo-controlled trial was to assess the preventive effect and safety of low-dose sotalol after heart operation. METHODS Two hundred fifty-five consecutive patients referred for elective coronary artery bypass grafting (n = 220) or aortic valve operation (n = 35) were randomized to receive either 80 mg of sotalol twice daily (n = 126) or matching placebo (n = 129) for 3 months, with the first dose given 2 hours before operation. RESULTS There were no significant baseline differences between the groups. Overall, supraventricular tachyarrhythmias occurred in 36% of patients (82% atrial fibrillation). Hospital stay was 11.6 +/- 5 days in patients with supraventricular arrhythmias, versus 9.5 +/- 2.4 days in patients without it (p < 0.0001). Low-dose sotalol reduced the rate of supraventricular arrhythmias from 46% (placebo) to 26% (sotalol; p = 0.0012), or by 43%. On the fourth postoperative day, heart rate was lower in the sotalol group (74 +/- 12 beats/min versus 85 +/- 15 beats/min; p < 0.0001) but the QT interval corrected for the heart rate was not prolonged (sotalol group, 0.44 +/- 0.03 second; placebo group, 0.43 +/- 0.03 second; p = not significant). Study medication had to be discontinued because of side effects in 5.6% of sotalol and 3.9% of placebo patients (p = not significant), with one possible proarrhythmic event occurring in a patient receiving sotalol. CONCLUSIONS Because more than 90% of supraventricular arrhythmic episodes occurred within 9 days after operation and 70% of all possibly sotalol related side effects occurred after day 9, the findings in this study imply that prophylactic treatment with sotalol may be limited to the first 9 postoperative days.

High incidence of intravenous thrombi after short-term central venous catheterization of the internal jugular vein

STUDY OBJECTIVE To assess incidence and characteristics of intravenous (i.v.) thrombi associated with short-term central venous catheterization through the internal jugular vein. DESIGN Prospective clinical study. SETTING University hospital. PATIENTS 81 patients undergoing cardiac surgery. INTERVENTIONS A triple-lumen central venous catheter was inserted into the right internal jugular vein immediately before surgery and removed 3 to 4 days later. Heparin at an i.v. dose of 15,000 IU/24 hours was started 6 hours after surgery and continued until the first postoperative morning, followed by subcutaneous low molecular weight heparin 5,000 IU/day in combination with oral aspirin 100 mg/day. MEASUREMENTS AND MAIN RESULTS Anatomy of the internal jugular vein and i.v. blood flow were studied using two-dimensional and color Doppler ultrasonography before insertion of the catheter and after its removal. Thrombi were found in 45 patients (56%). Twenty-five of these thrombi (56%) had the shape of a sleeve, and 20 thrombi (44%) were compact. Length of the thrombi was 1.4 +/- 0.8 cm (mean +/- SD). Half of the thrombi floated with venous blood flow and half were stable. Neither impaired venous blood flow nor clinical signs of embolism or sepsis was found. Follow-up studies in eight patients revealed that the thrombi had not disappeared 5 days after removal of the catheter but had become smaller. CONCLUSION The incidence of i.v. thrombi associated with short-term catheterization of the internal jugular vein was high despite prophylactic anticoagulation. This finding reaffirms the importance of removing central venous catheters as soon as clinically possible. Additional studies using specific outcome tests are needed to thoroughly assess the clinical importance of this finding.

Transesophageal Echocardiography for Monitoring Segmental Wall Motion During Off-pump Coronary Artery Bypass Surgery

In this prospective, observational study, we evaluated whether transesophageal echocardiography allows for monitoring left ventricular segmental wall motion during cardiac displacement for off-pump coronary artery bypass (OPCAB) surgery. On the basis of a pilot study that showed frequent loss of transgastric views during OPCAB surgery, we analyzed only midesophageal views. The midesophageal 4-chamber view, 2-chamber view, and long-axis view were recorded in 60 patients after opening the chest and placing an epicardial stabilizer on the displaced heart. Using the 16-segment model, 2 echocardiographers independently performed offline analysis of segmental wall motion. The percentage of patients in whom ≥14 left ventricular segments were readable was calculated at baseline and after cardiac displacement and placement of an epicardial stabilizer. At baseline, ≥14 segments were readable in 59 (98%) of 60 patients. After cardiac displacement, ≥14 segments were readable during 58 (76%) of 76 revascularizations of the left anterior descending coronary artery (P < 0.01 versus baseline), during 33 (83%) of 40 revascularizations of the left circumflex coronary artery (P < 0.01 versus baseline), and during 29 (94%) of 31 revascularizations of the right coronary artery (not significant). We conclude that the number of readable segments decreased after cardiac displacement but that availability of ≥14 readable segments allowed for reliable monitoring of segmental wall motion in 4 of 5 patients during OPCAB surgery.

Competence of the internal jugular vein valve is damaged by cannulation and catheterization of the internal jugular vein.

Background Experimental results suggest that the competence of the internal jugular vein (IJV) valve may be damaged when the IJV is cannulated for insertion of a central venous catheter. It has further been hypothesized that the risk of causing incompetence of the proximally located valve might be reduced by using a more distal site for venous cannulation. The present study evaluated these hypotheses in surgical patients. Methods Ninety-one patients without preexisting incompetence of the IJV valve were randomly assigned to undergo distal or proximal IJV cannulation (≥ 1 cm above or below the cricoid level, respectively). Color Doppler ultrasound was used to study whether new valvular incompetence was present during Valsalva maneuvers after insertion of a central venous catheter, immediately after removal of the catheter, and, in a subset of patients, several months after catheter removal, when compared with baseline findings before cannulation of the IJV. Results Incompetence of the IJV valve was frequently induced both by proximal and distal cannulation and catheterization of the IJV. Its incidence was higher after proximal than after distal cannulation (76%vs. 41%;P < 0.01) and tended to be so after removal of the catheter (47%vs. 28%;P = 0.07). Valvular incompetence persisting immediately after removal of the catheter did not recover within 8–27 months in most cases. Conclusions Cannulation and catheterization of the IJV may cause persistent incompetence of the IJV valve. Choosing a more distal site for venous cannulation may slightly lower the risk of causing valvular incompetence but does not reliably avoid it.

Significance of Supraventricular Tachyarrhythmias After Coronary Artery Bypass Graft Surgery and Their Prevention by Low-Dose Sotalol: A Prospective Double-Blind Randomized Placebo-Controlled Study

Background: The single most frequent complication after coronary artery bypass graft surgery is the occurrence of supraventricular tachyarrhythmias leading to a prolonged hospital stay. Although several drugs have been used to treat these arrhythmias, effective prevention was only possible with beta-blocking drugs in selected patients. It was, therefore, the aim of the present study to evaluate the significance of supraventricular tachyarrhythmias in presence of todays cardioprotective management in a broad spectrum of patients and to assess the possible preventive effect and safety of low-dose sotalol after coronary artery bypass graft surgery. Methods and Results: In a prospective randomized double-blind placebo-controlled trial, 220 consecutive patients referred for elective coronary artery bypass graft surgery were random ized to 80 mg sotalol twice daily (n = 110) or matching placebo (n = 110) for 3 months with the first dose given 2 hours before surgery. There were no significant differences in baseline charac teristics between the two groups. Low-dose sotalol reduced the rate of supraventricular arrhythmias from 43% (placebo) to 25% (sotalol, P <.01), which was atrial fibrillation in 83%, flutter in 7%, and other supraventricular arrhythmias in 10%. Only 7% of all arrhythmias were observed after day 9. Hospital stay was I 1 ± 4 days in patients with supraventricular arrhyth mias versus 9 ± 2 days (P < .001) in patients without. On the fourth postoperative day, heart rate was lower in the sotalol group (75 ± 12 versus 86 ± 14 beats per min; P < .0001), but QTc was not significantly prolonged (sotalol, 0.44 ± 0.03; placebo 0.43 ± 0.03; P. ns). Study medica tion had to be discontinued due to side effects in 6.4% of sotalol and 3.6% of placebo patients (P. ns), but relevant side effects occurred only in two sotalol patients late after surgery. Conclusions: These data show that without antiarrhythmic therapy the incidence of supraventricular arrhythmias after coronary artery bypass graft surgery is high (43%) and that supraventricular arrhythmias were associated with a prolonged hospital stay (+2 days). Prophylactic treatment with low-dose sotalol reduced the incidence of supraventricular arrhythmias significantly (by 40%), thereby reducing overall hospital stay in treated patients. Because more than 90% of all supraventricular arrhythmic episodes occurred within 10 days after surgery and considering the small proarrhythmic effect of sotalol late after surgery, prophylactic treatment with sotalol may be recommended for the first 10 postoperative days to safely reduce supraventricular tachyarrhythmias.

Dobutamine Stress Echocardiography to Detect Inducible Demand Ischemia in Anesthetized Patients with Coronary Artery Disease

Background A cardiac risk stratification test that can be performed during operation would be expected to give valuable information for the therapeutic management of patients who need urgent noncardiac surgery. This study was designed to evaluate the feasibility and safety of a dobutamine‐atropine stress protocol to detect inducible demand ischemia in anesthetized patients. Methods A standard dobutamine‐atropine stress protocol was performed in 80 patients with severe coronary artery disease during fentanyl‐isoflurane anesthesia. Biplane transesophageal echocardiography and 12‐lead electrocardiography were used to detect induced ischemia. After dobutamine testing, esmolol, nitroglycerin, or both were used to revert ischemia and any hemodynamic changes, as appropriate. Results The protocol detected inducible ischemia or achieved the target heart rate in 75 of the 80 (94%) patients. None of the prospectively defined adverse outcomes, such as cardiovascular collapse, severe ventricular arrhythmia, persistent (>or= to 5 min) ischemia, or hemodynamic instability, occurred in any of the patients. Ischemia was induced and detected in 73 of the 80 (91%) patients. Conclusion Dobutamine stress echocardiography is feasible in anesthetized patients with severe coronary artery disease. The lack of serious complications and the high sensitivity to detect inducible ischemia in this patient population provide the basis for further evaluation of the safety and diagnostic value of dobutamine stress echocardiography during general anesthesia in larger studies of patients at risk for coronary artery disease undergoing noncardiac surgery.

Additional Cross-sectional Transesophageal Echocardiography Views Improve Perioperative Right Heart Assessment

Background:Right heart failure is an important cause of perioperative morbidity and mortality, and transesophageal echocardiography (TEE) is crucial for its diagnosis. However, only four of the 20 cross-sectional views recommended in current guidelines for intraoperative TEE focus on the right heart. This study analyzed whether incorporating additional views into the standard TEE examination improves assessment of the right heart. Methods:Sixty patients underwent standard TEE examination after induction of anesthesia. In addition, five views focusing on the right heart were acquired. Offline analysis tested: (1) whether the additional TEE views can be acquired as reliably as standard views including parts of the right heart; whether incorporating additional views improves the assessment of (2) eight or more right ventricular wall segments based on a predefined nine-segment model; (3) the tricuspid or pulmonary valve in two or more planes; and (4) transvalvular tricuspid and pulmonary flow in orthograde fashion. Results:Additional views could be imaged as reliably (88%) as standard views (90%). Incorporating some of the additional views allowed the assessment of eight or more right ventricular segments in 59 (98%) versus 18 patients (30%) by the standard views alone, and of the pulmonary valve in two or more planes in 60 (100%) versus 15 patients (25%). Several additional views improved orthograde assessment of transvalvular pulmonary flow, but not of tricuspid flow. Conclusions:The additional TEE views focusing on the right heart can be acquired as reliably as standard views. Incorporating three of them into the standard TEE examination improves comprehensive assessment of the right heart.

Immediate effects of mitral valve replacement on left ventricular function and its determinants.

Patients undergoing mitral valve surgery are at risk of left ventricular failure in the immediate post-operative period. In order to understand better the mechanisms of post-operative haemodynamic instability, we used transoesophageal echocardiography to assess the immediate response of the left ventricle to mitral valve replacement for mitral regurgitation or stenosis. A decrease in left ventricular preload, despite adequate filling pressures, was common to both groups and suggests the presence of diastolic dysfunction. A marked impairment in global systolic pump function was observed only in the regurgitation group and correlated with the left ventricular afterload. Transoesophageal echocardiography provides valuable information on the individual changes in left ventricular function and its determinants after mitral valve replacement that are not reflected by haemodynamic measurements.

Transient recurrent laryngeal nerve palsy after failed placement of a transesophageal echocardiographic probe in an anesthetized patient.

We performed aortic valve replacement in an otherwise healthy 25-yr-old man (181 cm, 63 kg) with congenital aortic valve disease without intraoperative TEE monitoring because TEE probe insertion (5.0/3.7 TEE probe; HewlettPackard, Andover, MA) in this anesthetized patient was unsuccessful. When a paravalvular leak was suspected 4 days after uneventful surgery, TEE examination with an identical probe was feasible in the left-sided, awake patient. A paravalvular leak with a regurgitation volume of 50% was confirmed, and the patient was scheduled for reoperation. Again, the perioperative plan included TEE monitoring. General anesthesia was induced, and the patient’s trachea was intubated with an 8.5-mm inner diameter, low-pressure, high-volume cuff tube. Central venous access was achieved by cannulation of the right internal jugular vein. Blind insertion of a slightly smaller TEE probe (6.2/5.0 TEE probe; Hewlett Packard, Andover, MA) than had been previously used was attempted but was unsuccessful. Laryngoscopy allowed visualization of the larynx, but insertion of the TEE probe into the esophagus was stopped after 1 cm by a hard resistance. The echocardiographer’s impression was that the probe was stuck between the anterior thyroid and cricoid cartilages and the posterior vertebra of the extremely lean patient. Several ways of repositioning the patient’s head and neck did not resolve the problem, and the intention to monitor by TEE had to be abandoned again. The same surgeon performed the second uneventful surgical procedure, and the same technique was used for preparation of the heart and for myocardial protection (cold cardioplegia without local cooling). After extubation in the intensive care unit, the sufficiently breathing patient complained about hoarseness. A laryngeal examination revealed palsy of the left recurrent laryngeal nerve without any other pathology. Recurrent laryngeal nerve palsy and hoarseness resolved by themselves on the eighth postoperative day.

The inverse Nehb J lead increases the sensitivity of Holter electrocardiographic monitoring for detecting myocardial ischemia

A major reason for the relatively low sensitivity of Holter electrocardiography (ECG) for detecting ischemia is that the sensitivity of bipolar leads used for Holter ischemia monitoring has not been systematically evaluated, making lead selection difficult. Therefore, this study evaluated the sensitivity of 6 bipolar Holter leads for detecting ischemia during percutaneous transluminal coronary angioplasty. Seventy-five patients, each of whom had > 1 mm ST-segment elevation on an intracoronary electrocardiogram from the myocardium distal to the stenosis during balloon occlusion, were studied for the occurrence of > or = 1 mm ST-segment elevation or depression on the simultaneously recorded Holter leads II, III, aVF, CM5, CR4, and inverse Nehb J. The study found that the inverse lead Nehb J provided a significantly higher overall sensitivity for detecting myocardial ischemia than Holter leads II, III, aVF, CM5, and CR4. Also, the use of inverse lead Nehb J significantly increased the sensitivity of 2- and 3-lead Holter ischemia monitoring. These findings were based on a significantly higher sensitivity of inverse lead Nehb J for detecting ischemia induced by transient occlusion of the left anterior descending coronary artery and a slightly higher sensitivity for detecting ischemia induced by occlusion of the left circumflex coronary artery. None of the bipolar leads studied provided a very high sensitivity for detecting ischemia induced by occlusion of the right coronary artery. These findings show that adequate lead selection can increase the sensitivity of Holter ischemia monitoring. Furthermore, the lack of a highly sensitive lead for detection of inferior ischemia indicates that further evaluation of bipolar leads is warranted.