Torvind Næsheim

“Nobody is dead until warm and dead”: Prolonged resuscitation is warranted in arrested hypothermic victims also in remote areas – A retrospective study from northern Norway

Hypothermic cardiac arrest has high mortality and few known prognostic factors. We studied retrospectively 34 victims of accidental hypothermia with cardiac arrest admitted to The University Hospital of North Norway during 1985-2013 who were resuscitated and rewarmed by extracorporeal circulation. No patient survived prior to 1999, while nine out of 24 (37.5%) survived hypothermic cardiac arrest from 1999 to 2013. The lowest measured core temperature among survivors was 13.7°C; the longest time from cardiac arrest to return of spontaneous circulation was 6 h and 52 min. The only predictor of survival identified was lower blood potassium concentration in the nine survivors compared with the non-survivors. Submersion was not associated with reduced survival. Non-survivors consumed modest hospital resources. Most survivors had a favourable neurological outcome.

Myosin Activator Omecamtiv Mecarbil Increases Myocardial Oxygen Consumption and Impairs Cardiac Efficiency Mediated by Resting Myosin ATPase Activity

Background—Omecamtiv mecarbil (OM) is a novel inotropic agent that prolongs systolic ejection time and increases ejection fraction through myosin ATPase activation. We hypothesized that a potentially favorable energetic effect of unloading the left ventricle, and thus reduction of wall stress, could be counteracted by the prolonged contraction time and ATP-consumption. Methods and Results—Postischemic left ventricular dysfunction was created by repetitive left coronary occlusions in 7 pigs (7 healthy pigs also included). In both groups, systolic ejection time and ejection fraction increased after OM (0.75 mg/kg loading for 10 minutes, followed by 0.5 mg/kg/min continuous infusion). Cardiac efficiency was assessed by relating myocardial oxygen consumption to the cardiac work indices, stroke work, and pressure–volume area. To circumvent potential neurohumoral reflexes, cardiac efficiency was additionally assessed in ex vivo mouse hearts and isolated myocardial mitochondria. OM impaired cardiac efficiency; there was a 31% and 23% increase in unloaded myocardial oxygen consumption in healthy and postischemic pigs, respectively. Also, the oxygen cost of the contractile function was increased by 63% and 46% in healthy and postischemic pigs, respectively. The increased unloaded myocardial oxygen consumption was confirmed in OM-treated mouse hearts and explained by an increased basal metabolic rate. Adding the myosin ATPase inhibitor, 2,3-butanedione monoxide abolished all surplus myocardial oxygen consumption in the OM-treated hearts. Conclusions—Omecamtiv mecarbil, in a clinically relevant model, led to a significant myocardial oxygen wastage related to both the contractile and noncontractile function. This was mediated by that OM induces a continuous activation in resting myosin ATPase.

Transcatheter aortic-valve implantation for aortic stenosis.

BACKGROUND Short-term results are presented from our first year of experience with transcatheter aortic-valve implantation [corrected] (TAVI) at the University Hospital of North Norway. MATERIALS AND METHODS TAVI was used to treat 25 patients with aortic stenosis [corrected] from September 2008 to August 2009. 25 patients operated with conventional aortic valve replacement (AVR) served as controls. RESULTS The TAVI group had a significantly higher EuroSCORE (p < 0.001) than the AVR group. No patients in the TAVI group were treated in the intensive care unit while those in the AVR group received 38 days of intensive care in total. The TAVI group had shorter operating times (p < 0.001), larger mean valve sizes (p < 0.001) and significantly fewer postoperative transfusions (p < 0.001) than the ACR group. Peri-operative stroke and myocardial infarction did not occur in the TAVI group while there was one incidence of stroke and one myocardial infarction in the AVR group. The postoperative transvalvular mean gradient decreased in both groups (p < 0.001) and was significantly lower in the TAVI group (p = 0.001). The NYHA class improved significantly in the TAVI group (p < 0.001). No patients needed implantation of a permanent pacemaker. 30-day mortality was four patients in the AVR group and one patient in the TAVI group. After discharge one patient died in each group. INTERPRETATION TAVI is safe and effective for selected patients with aortic stenosis [corrected] who are assessed as high risk for AVR. Long-term results are needed and will be decisive for use of this approach in the future.

Hypothermic cardiac arrest far away from the center providing rewarming with extracorporeal circulation

A 41-year-old man suffered hypothermic cardiac arrest after water immersion and was transported to our university hospital by ambulance helicopter for rewarming on cardiopulmonary bypass. He resumed spontaneous cardiac activity 6 h 52 min after cardiac arrest and recovered completely.

Adenosine instead of supranormal potassium in cardioplegia: It is safe, efficient, and reduces the incidence of postoperative atrial fibrillation. A randomized clinical trial

OBJECTIVE We aimed to evaluate the efficacy and safety of a cold crystalloid cardioplegic solution with adenosine (1.2 mmol/L) instead of supranormal potassium. METHODS Sixty low-risk patients scheduled for elective coronary artery bypass grafting (CABG) were randomized to receive standard cold crystalloid hyperkalemic cardioplegia (hyperkalemic group) or normokalemic cardioplegia in which supranormal potassium was replaced with 1.2 mmol/L adenosine (adenosine group). End points were postoperative release of troponin T and creatine kinase MB, hemodynamics measured by PiCCO arterial thermodilution catheters, perioperative release of markers of endothelial activation and injury, and clinical course. RESULTS The adenosine group had a significantly shorter time to arrest than did the hyperkalemic group (mean ± standard deviation, 11 ± 5 vs 44 ± 18 seconds; P < .001). Three hearts in the adenosine group were probably not adequately drained and received additional hyperkalemic cardioplegia to maintain satisfactory cardioplegic arrest. There were no differences between groups with respect to perioperative release of markers of endothelial activation or injury and no differences between groups in postoperative release of troponin T or creatine kinase MB. Postoperative hemodynamics including cardiac index were similar between groups. The incidence of postoperative atrial fibrillation was significantly lower in the adenosine group than in the hyperkalemic group (4 vs 15; P = .01). CONCLUSIONS Adenosine instead of hyperkalemia in cold crystalloid cardioplegia is safe, gives more rapid cardiac arrest, and affords similar cardioprotection and maintenance of hemodynamic parameters, together with a marked reduction in the incidence of postoperative atrial fibrillation.

Reversing dobutamine-induced tachycardia using ivabradine increases stroke volume with neutral effect on cardiac energetics in left ventricular post-ischaemia dysfunction.

Compensatory tachycardia can potentially be deleterious in acute heart failure. In this study, we tested a therapeutic strategy of combined inotropic support (dobutamine) and selective heart rate (HR) reduction through administration of ivabradine.

Circulatory assistance in acute heart failure--where do we go from here?

The comment concerns two short-term assist systems, namely the Impella axial-flow recovery system and extra-corporeal membrane oxygenation (ECMO) used for circulatory assistance in patients with acute heart failure. The results, particularly for patients in cardiogenic shock not related to cardiac surgery, calls for cautious optimism.

Propulsion of blood through the right heart circulatory system

Abstract Venous return, the right heart function and the pulmonary circulation is an integrated functional unit. The right ventricle is particularly load sensitive, and will be influenced directly by the venous and pulmonary physiology. In this paper we present important physiological principles that govern the diagnosis and treatment of dysfunctions affecting the return of blood to the heart and the transfer of the cardiac output from the right to the left side. We do evaluate both basic science and the clinical literature pointing to practical aspects of physiological knowledge.

Response to Letter Regarding Article, “Myosin Activator Omecamtiv Mecarbil Increases Myocardial Oxygen Consumption and Impairs Cardiac Efficiency Mediated by Resting Myosin ATPase Activity”

We certainly appreciate the swift response1 from the group of scientists who have put so much work into the development of omecamtiv mecarbil. Their joint effort is remarkable. However, as Malik and Morgan have stated previously “…omecamtiv mecarbil might increase ATP turnover at the level of the sarcomere…,”2 and this is clearly demonstrated in Figure 4D of their article. Thus, the main aim in our study3 was assessing this aspect’s impact on cardiac efficiency. A study in conscious dogs4 has the advantage of minimizing surgical and pharmacological interventions, but it precludes the ability to decipher the relation between contractile work and energy consumption. In our view, the Suga-model we have used …