Pulseless Electrical Activity: Echocardiographic Explanation of a Perplexing Phenomenon.

Pulseless electrical activity (PEA) is considered an enigmatic phenomenon in resuscitation research and practice. Finding individuals with no consciousness or pulse but with continued electrocardiographic (EKG) complexes obviously raises the question of how they got there. The development of monitors that can display the underlying rhythm has allowed us to differentiate between VF, asystole, and PEA. Lack of clear understanding of the emergence of PEA has limited the research and development of interventions that might improve the low rates of survival typically associated with PEA. Over 30 years of studying and practicing resuscitation have allowed the authors to see a substantial rise in PEA with variable survival rates, based on the patients' illness spectrum and intensity of monitoring. This paper presents a small case series of individuals with brain death whose family members consented to the echocardiographic observation of the dying process after disconnection from life support. The observation from these cases confirms that PEA is a late phase in the clinical dying process. Echocardiographic images delineate the stages of pseudo-PEA with ineffective contractions, PEA, and then asystole. The process is contiuous with none of the sudden phase shifts seen in dysrhythmic events such as VF, VT or SVT. The implications of these findings are that PEA is a common manifestation of tissue hypoxia and metabolic substrate depletion. Our findings offer prospects for studies of the development of interventions to improve PEA survival.

Stellate Ganglion Blockade and Left Cardiac Sympathetic Denervation With Left Stellate Ganglionectomy in a Patient With Refractory Electrical Storm: A Case Report.

Electrical storm (ES) is classified as at least three episodes of ventricular tachycardia (VT) or ventricular fibrillation (VF) in any 24-hour period. Stellate ganglion blockade and left stellate ganglionectomy have shown benefit in terminating ES. A 64-year-old white male with a past medical history of atrial fibrillation, coronary artery disease requiring previous cardiac bypass surgery in 1997, and coronary artery stents in 2003 presented with syncope and refractory ventricular tachycardia/fibrillation. He eventually underwent both an ultrasound-guided left stellate ganglion block and left cardiac sympathetic denervation with left stellate ganglionectomy. In the setting of refractory ES, the left stellate ganglion block followed by left stellate ganglionectomy can be a lifesaving intervention.

Ventricular Fibrillation 7 Years After Left Ventricular Assist Device Implantation.

BACKGROUND Congestive heart failure (CHF) affects over 23 million individuals worldwide and over 5.8 million individuals in the United States. Left ventricular assist device (LVAD) implantation is used as both a bridging and destination therapy for patients with advanced CHF. LVADs are reported to cause ventricular arrhythmias. Ventricular tachycardia and ventricular fibrillation (VF) are common fatal arrhythmias in patients with severe CHF if left untreated. We report a case in which a patient with an LVAD without an implantable cardioverter device (ICD) developed VF with non-classical symptoms with an unknown duration prior to defibrillation. CASE REPORT A 74-year old man was brought to the hospital via Emergency Medical Services (EMS) with a 1-day history of altered mental status, somnolence, and slurred speech. His past medical history was significant for CHF with LVAD Heart Mate II. An initial electrocardiogram (ECG) done by EMS was abnormal but was presumed to be an artifact secondary to LVAD. A 12-lead ECG done in the Emergency Center revealed VF. He required electrical defibrillation. Due to ongoing multiple organ failure, he was admitted to the Intensive Care Unit (ICU) for further care. CONCLUSIONS In the management of VF, the time to defibrillation is of paramount importance. LVAD patients could be in VF and present with non-specific symptoms. EMS personnel should be aware of this, as it can appear to be an artifact on ECG.

Early outcomes with utilization of tissue plasminogen activator in COVID-19-associated respiratory distress: A series of five cases.

BACKGROUND: Coronavirus patients demonstrate varying degrees of respiratory insufficiency; many will progress to respiratory failure with a severe version of acute respiratory distress syndrome refractory to traditional supportive strategies. Providers must consider alternative therapies to deter or prevent the cascade of decompensation to fulminant respiratory failure. METHODS: This is a case-series of five COVID-19 positive patients who demonstrated severe hypoxemia, declining respiratory performance, and escalating oxygen requirements. Patients met the following criteria: COVID-19 positivity, worsening respiratory performance, severe hypoxemia (PaO2 ≤ 80) despite traditional supportive measures, escalating supplemental oxygen requirements, and D-dimer greater than 1.5 µg/mL. All patients received protocol directed thrombolytic therapy with tissue plasminogen activator (tPA). RESULTS: All five patients improved without deleterious effects of thrombolytic therapy. Patient one was on maximum ventilator support, paralytics, and prone positioning without improvement. During tPA administration his PaO2/FIO2 ratio improved from 69 to 127. Ventilator support was weaned immediately on posttreatment day 1, and he was extubated on posttreatment day 12. Our second through fifth patients were not intubated at time of initiation of tPA therapy. These patients each required significant oxygen supplementation trending toward intubation. After tPA therapy, all patients demonstrated a noticeable increase in PaO2 values overtime. Three of these patients avoided intubation due to COVID-19-associated respiratory failure. CONCLUSION: Administration of thrombolytics was followed by overall improvement in patients' oxygen requirements, and in three cases, prevented progression to mechanical ventilation, without deleterious effects. Clinical trials of thrombolytic therapy would further serve to underscore the efficacy and utility of this therapy. LEVEL OF EVIDENCE: Case series of therapeutic effect, Level V.

Steroidogenic acute regulatory protein/aldosterone synthase mediates angiotensin II-induced cardiac fibrosis and hypertrophy.

Aldosterone produced in adrenal glands by angiotensin II (Ang II) is known to elicit myocardial fibrosis and hypertrophy. This study was designed to test the hypothesis that Ang II causes cardiac morphological changes through the steroidogenic acute regulatory protein (StAR)/aldosterone synthase (AS)-dependent aldosterone synthesis primarily initiated in the heart. Sprague-Dawley rats were randomized to following groups: Ang II infusion for a 4-week period, treatment with telmisartan, spironolactone or adrenalectomy during Ang II infusion. Sham-operated rats served as control. Relative to Sham rats, Ang II infusion significantly increased the protein levels of AT1 receptor, StAR, AS and their tissue expression in the adrenal glands and heart. In coincidence with reduced aldosterone level in the heart, telmisartan, an AT1 receptor blocker, significantly down-regulated the protein level and expression of StAR and AS. Ang II induced changes in the expression of AT1/StAR/AS were not altered by an aldosterone receptor antagonist spironolactone. Furthermore, Ang II augmented migration of macrophages, protein level of TGFß1, phosphorylation of Smad2/3 and proliferation of myofibroblasts, accompanied by enhanced perivascular/interstitial collagen deposition and cardiomyocyte hypertrophy, which all were significantly abrogated by telmisartan or spironolactone. However, adrenalectomy did not fully suppress Ang II-induced cell migration/proliferation and fibrosis/hypertrophy, indicating a role of aldosterone synthesized within the heart in pathogenesis of Ang II induced injury. These results indicate that myocardial fibrosis and hypertrophy stimulated by Ang II is associated with tissue-specific activation of aldosterone synthesis, primarily mediated by AT1/StAR/AS signaling pathways.

Liraglutide attenuates cardiac remodeling and improves heart function after abdominal aortic constriction through blocking angiotensin II type 1 receptor in rats.

OBJECTIVE: Angiotensin II (Ang II) is known to contribute to the pathogenesis of heart failure by eliciting cardiac remodeling and dysfunction. The glucagon-like peptide-1 (GLP-1) has been shown to exert cardioprotective effects in animals and patients. This study investigates whether GLP-1 receptor agonist liraglutide inhibits abdominal aortic constriction (AAC)-induced cardiac fibrosis and dysfunction through blocking Ang II type 1 receptor (AT1R) signaling. METHODS: Sprague-Dawley rats were subjected to sham operation and abdominal aortic banding procedure for 16 weeks. In treated rats, liraglutide (0.3 mg/kg) was subcutaneously injected twice daily or telmisartan (10 mg/kg/day), the AT1R blocker, was administered by gastric gavage. RESULTS: Relative to the animals with AAC, liraglutide reduced protein level of the AT1R and upregulated the AT2R, as evidenced by reduced ratio of AT1R/AT2R (0.59±0.04 vs. 0.91±0.06, p<0.05). Furthermore, the expression of angiotensin converting enzyme 2 was upregulated, tissue levels of malondialdehyde and B-type natriuretic peptide were reduced, and superoxide dismutase activity was increased. Along with a reduction in HW/BW ratio, cardiomyocyte hypertrophy was inhibited. In coincidence with these changes, liraglutide significantly decreased the populations of macrophages and myofibroblasts in the myocardium, which were accompanied by reduced protein levels of transforming growth factor beta1, Smad2/3/4, and upregulated smad7. The synthesis of collagen I and III was inhibited and collagen-rich fibrosis was attenuated. Consistent with these findings, cardiac systolic function was preserved, as shown by increased left ventricular systolic pressure (110±5 vs. 99±2 mmHg, p<0.05), ejection fraction (83%±2% vs. 69%±4%, p<0.05) and fraction shortening (49%±2% vs. 35%±3%, p<0.05). Treatment with telmisartan provided a comparable level of protection as compared with liraglutide in all the parameters measured. CONCLUSION: Taken together, liraglutide ameliorates cardiac fibrosis and dysfunction, potentially via suppressing the AT1R-mediated events. These data indicate that liraglutide might be selected as an add-on drug to prevent the progression of heart failure.

CD44 Deficiency in Mice Protects the Heart Against Angiotensin Ii-Induced Cardiac Fibrosis.

This study tested the hypothesis that CD44 is involved in the development of cardiac fibrosis via angiotensin II (Ang II) AT1 receptor-stimulated TNFα/NFκB/IκB signaling pathways. Study was conducted in C57BL/6 wild type and CD44 knockout mice subjected to Ang II infusion (1,000 ng/kg/min) using osmotic minipumps up to 4 weeks or with gastric gavage administration of the AT1 receptor blocker, telmisartan at a dose of 10 mg/kg/d. Results indicated that Ang II enhances expression of the AT1 receptor, TNFα, NFκB, and CD44 as well as downregulates IκB. Further analyses revealed that Ang II increases macrophage migration, augments myofibroblast proliferation, and induces vascular/interstitial fibrosis. Relative to the Ang II group, treatment with telmisartan significantly reduced expression of the AT1 receptor and TNFα. These changes occurred in coincidence with decreased NFκB, increased IκB, and downregulated CD44 in the intracardiac vessels and intermyocardium. Furthermore, macrophage migration and myofibroblast proliferation were inhibited and fibrosis was attenuated. Knockout of CD44 did not affect Ang II-stimulated AT1 receptor and modulated TNFα/NFκB/IκB signaling, but significantly reduced macrophage/myofibroblast-mediated fibrosis as identified by less extensive collagen-rich area. These results suggest that the AT1 receptor is involved in the development of cardiac fibrosis by stimulating TNFα/NFκB/IκB-triggered CD44 signaling pathways. Knockout of CD44 blocked Ang II-induced cell migration/proliferation and cardiac fibrosis. Therefore, selective inhibition of CD44 may be considered as a potential therapeutic target for attenuating Ang II-induced deleterious cardiovascular effects.

Edaravone inhibits pressure overload-induced cardiac fibrosis and dysfunction by reducing expression of angiotensin II AT1 receptor.

Angiotensin II (Ang II) is known to be involved in the progression of ventricular dysfunction and heart failure by eliciting cardiac fibrosis. The purpose of this study was to demonstrate whether treatment with an antioxidant compound, edaravone, reduces cardiac fibrosis and improves ventricular function by inhibiting Ang II AT1 receptor. The study was conducted in a rat model of transverse aortic constriction (TAC). In control, rats were subjected to 8 weeks of TAC. In treated rats, edaravone (10 mg/kg/day) or Ang II AT1 receptor blocker, telmisartan (10 mg/kg/day) was administered by intraperitoneal injection or gastric gavage, respectively, during TAC. Relative to the animals with TAC, edaravone reduced myocardial malonaldehyde level and increased superoxide dismutase activity. Protein level of the AT1 receptor was reduced and the AT2 receptor was upregulated, as evidenced by the reduced ratio of AT1 over AT2 receptor (0.57±0.2 vs 3.16±0.39, p<0.05) and less locally expressed AT1 receptor in the myocardium. Furthermore, the protein level of angiotensin converting enzyme 2 was upregulated. In coincidence with these changes, edaravone significantly decreased the populations of macrophages and myofibroblasts in the myocardium, which were accompanied by reduced levels of transforming growth factor beta 1 and Smad2/3. Collagen I synthesis was inhibited and collagen-rich fibrosis was attenuated. Relative to the TAC group, cardiac systolic function was preserved, as shown by increased left ventricular systolic pressure (204±51 vs 110±19 mmHg, p<0.05) and ejection fraction (82%±3% vs 60%±5%, p<0.05). Treatment with telmisartan provided a comparable level of protection as compared with edaravone in all the parameters measured. Taken together, edaravone treatment ameliorates cardiac fibrosis and improves left ventricular function in the pressure overload rat model, potentially via suppressing the AT1 receptor-mediated signaling pathways. These data indicate that edaravone might be selected in combination with other existing drugs in preventing progression of cardiac dysfunction in heart failure.

Clinical and quality of life comparison of accelerometer, piezoelectric crystal, and blended sensors in DDDR-paced patients with sinus node dysfunction in the mode selection trial (MOST).

INTRODUCTION: Permanent pacemakers are capable of increasing heart rate in response to physical activity by a variety of sensors including accelerometers, piezoelectric crystals, or blended sensors. The impact of these different physiologic sensors on cardiovascular events and quality of life is not known. METHODS: Of 2,010 patients randomized in the Mode Selection Trial, 1,245 patients were selected with the most commonly used pacemakers with these three sensors. Clinical characteristics and quality of life were compared between groups at baseline, 3 months, and then yearly. RESULTS: There were 449 patients with an accelerometer sensor device, 682 with a piezoelectric sensor, and 114 with a blended sensor. The groups were similar in terms of age (mean 74 years), gender, and cardiac risk factors but differences existed in weight, heart rate, mitral regurgitation, revascularization history, and drug therapy. The median ventricular pacing frequency was 80% (25th, 75th percentiles 42, 97). After a median follow-up of 33.1 months, the risk of death, heart failure hospitalization, atrial fibrillation, and the combined endpoint of mortality and stroke was not significantly different between the sensor types, after adjustment for baseline differences. Quality of life analyses demonstrated that patients with blended sensors had significantly worse (P < 0.01) physical function than did patients with the other two sensor systems. Moreover, patients receiving blended sensors had the poorest absolute scores, without reaching statistical significance, on 9 of 13 quality of life measures after adjusting for differences in the groups. CONCLUSION: We found no significant differences among the three most utilized sensors in clinical endpoints. Those patients who received blended sensors had worse physical function quality of life scores. However, clinical selection of the most sophisticated sensor for the most ill patients cannot be excluded as an explanation of these results.

Heart failure hospitalization is more common in pacemaker patients with sinus node dysfunction and a prolonged paced QRS duration.

OBJECTIVES: The purpose of this study was to determine whether a prolonged paced QRS duration increases the risk of cardiac dysfunction. BACKGROUND: Right ventricular apical pacing mimics left bundle branch block, results in a prolonged QRS duration of variable duration, and causes ventricular desynchronization. METHODS: In the Mode Selection Trial (MOST), QRS duration was measured in patients who had at least one paced ventricular complex recorded on 12-lead ECG within 3 months of enrollment (early) and after 9 months (late). Clinical endpoints including heart failure hospitalization, mortality, and atrial fibrillation were analyzed. A total of 1,026 patients were included in the analysis. Median age was 75 years (25th, 75th percentiles = 69, 80) and median ejection fraction prior to implant was 55% (45, 60). The cumulative percent ventricular pacing (DDDR and VVIR) was 81% over a median follow-up of 33 months. During period, 123 patients had heart failure hospitalization, 197 died, and 261 patients had atrial fibrillation. RESULTS: Cox proportional hazards models demonstrated that paced QRS duration was a strong predictor of heart failure hospitalization (hazard ratio 1.15; 95% confidence interval 1.07,1.23) for each 10-ms increase in paced QRS duration (P = .001). The increased risk was unaffected by adjustment for other known predictors of heart failure hospitalization in the study. Paced QRS duration was not significant for mortality (P = .41) or atrial fibrillation (P = .20) when baseline QRS duration and other predictors were included. CONCLUSIONS: Paced QRS duration is a significant, independent predictor of heart failure hospitalization in patients with sinus node dysfunction. A very long paced QRS duration is associated with increased heart failure hospitalization.

Prevention of cardiovascular complications of diabetes mellitus by aspirin.

Eighteen million Americans have type 2 Diabetes Mellitus (DM) while another 40 million have impaired glucose tolerance. Atherosclerotic heart disease is the leading cause of death in patients with diabetes mellitus. In addition to the increased risk for CardioVascular Disease (CVD), patients with diabetes have a worse prognosis than nondiabetics when they suffer an ischemic event. Insulin resistance is increasingly recognized as a chronic, low-level, inflammatory state. Hyperinsulinemia has been proposed as the forerunner of hypertension, low high-density lipoprotein cholesterolemia, hypertriglyceridemia, abdominal obesity, and altered glucose tolerance, linking all these abnormalities to the development of coronary vascular disease. Atherosclerosis and insulin resistance share similar pathophysiological mechanisms, due to the actions of proinflammatory cytokines. The dynamic inflammatory milieu found in diabetes explains the susceptibility of diabetics to CVD and the potential mechanism by which aspirin may prevent CVD in diabetics. Aspirin decreases the risk for CVD in diabetic patients by a variety of established and novel mechanisms. Therapeutic strategies that lesson the CVD risk in diabetic patients, including the use of aspirin for primary and secondary prevention, are potentially very important. This review article addresses the antiatherosclerotic effects of aspirin, the potential anti-diabetic effects of aspirin, and the clinical trial evidence for CVD prevention by aspirin in diabetics. We also present recommendations for the use of aspirin in the diabetic population and the current guidelines put forth by the American Heart Association and by the American Diabetes Association.

Window to the heart: the value of a native and paced QRS duration. Current perspective and review.

Given the technological advances and reliance upon expensive testing for guiding therapy, it is surprising how an inexpensive, low tech electrocardiogram can provide a wealth of information pertaining to the underlying cardiovascular status of a patient. In this article we review the changes in hemodynamics, prognosis and guidance of therapeutic options associated with a prolonged QRS duration.