A large, multi-center survey assessing health, social support, literacy, and self-management resources in patients with heart failure.

BACKGROUND: Most patients with heart failure (HF) have multimorbidity which may cause difficulties with self-management. Understanding the resources patients draw upon to effectively manage their health is fundamental to designing new practice models to improve outcomes in HF. We describe the rationale, conceptual framework, and implementation of a multi-center survey of HF patients, characterize differences between responders and non-responders, and summarize patient characteristics and responses to the survey constructs among responders. METHODS: This was a multi-center cross-sectional survey study with linked electronic health record (EHR) data. Our survey was guided by the Chronic Care Model to understand the distribution of patient-centric factors, including health literacy, social support, self-management, and functional and mental status in patients with HF. Most questions were from existing validated questionnaires. The survey was administered to HF patients aged ≥ 30 years from 4 health systems in PCORnet® (the National Patient-Centered Clinical Research Network): Essentia Health, Intermountain Health, Mayo Clinic, and The Ohio State University. Each health system mapped their EHR data to a standardized PCORnet Common Data Model, which was used to extract demographic and clinical data on survey responders and non-responders. RESULTS: Across the 4 sites, 10,662 patients with HF were invited to participate, and 3330 completed the survey (response rate: 31%). Responders were older (74 vs. 71 years; standardized difference (95% CI): 0.18 (0.13, 0.22)), less racially diverse (3% vs. 12% non-White; standardized difference (95% CI): -0.32 (-0.36, -0.28)), and had higher prevalence of many chronic conditions than non-responders, and thus may not be representative of all HF patients. The internal reliability of the validated questionnaires in our survey was good (range of Cronbach's alpha: 0.50-0.96). Responders reported their health was generally good or fair, they frequently had cardiovascular comorbidities, > 50% had difficulty climbing stairs, and > 10% reported difficulties with bathing, preparing meals, and using transportation. Nearly 80% of patients had family or friends sit with them during a doctor visit, and 54% managed their health by themselves. Patients reported generally low perceived support for self-management related to exercise and diet. CONCLUSIONS: More than half of patients with HF managed their health by themselves. Increased understanding of self-management resources may guide the development of interventions to improve HF outcomes.

Hypothermia improves defibrillation success and resuscitation outcomes from ventricular fibrillation.

BACKGROUND: Induced hypothermia is recommended to improve neurological outcomes in unconscious survivors of out-of-hospital ventricular fibrillation (VF) cardiac arrest. Patients resuscitated from a VF arrest are at risk of refibrillation, but there are few data on the effects of already existing hypothermia on defibrillation and resuscitation. METHODS AND RESULTS: Thirty-two swine (mean+/-SE weight, 23.0+/-0.6 kg) were divided into 4 groups: normothermia (n=8), mild hypothermia (35 degrees C) (n=8), moderate hypothermia (33 degrees C) (n=8), and severe hypothermia (30 degrees C) (n=8). Hypothermia was induced by surrounding the animal with ice, and VF was electrically induced. After 8 minutes of unsupported VF (no CPR), the swine were defibrillated (biphasic waveform) with successive shocks as needed and underwent CPR until resumption of spontaneous circulation or no response (> or =10 minutes). First-shock defibrillation success was higher in the moderate hypothermia group (6 of 8 hypothermia versus 1 of 8 normothermia; P=0.04). The number of shocks needed for late defibrillation (> or =1 minute after initial shock) was less in all 3 hypothermia groups compared with normothermia (all P<0.05). None of the 8 animals in the normothermia group achieved resumption of spontaneous circulation compared with 3 of 8 mild hypothermia (P=NS), 7 of 8 moderate hypothermia (P=0.001), and 5 of 8 severe hypothermia (P=0.03) animals. Coronary perfusion pressure during CPR was not different between the groups. CONCLUSIONS: When VF was induced in the setting of moderate or severe hypothermia, resuscitative measures were facilitated with significantly improved defibrillation success and resuscitation outcome. The beneficial effect of hypothermia was not due to alteration of coronary perfusion pressure, which suggests that changes in the mechanical, metabolic, or electrophysiological properties of the myocardium may be responsible.

Triphasic waveforms are superior to biphasic waveforms for transthoracic defibrillation: experimental studies.

OBJECTIVES: Our objective was to evaluate the efficacy of triphasic waveforms for transthoracic defibrillation in a swine model. BACKGROUND: Triphasic shocks have been found to cause less post-shock dysfunction than biphasic shocks in chick embryo studies. METHODS: After 30 s of electrically induced ventricular fibrillation (VF), each pig in part I (n = 32) received truncated exponential biphasic (7.2/7.2 ms) and triphasic (4.8/4.8/4.8 ms) transthoracic shocks. Each pig in part II (n = 14) received biphasic (5/5 ms) and triphasic shocks (5/5/5 ms). Three selected energy levels (50, 100, and 150 J) were tested for parts I and II. Pigs in part III (n = 13) received biphasic (5/5 ms) and triphasic (5/5/5 ms) shocks at a higher energy (200 and 300 J). Although the individual pulse durations of these shocks were equal, the energy of each pulse varied. Nine pigs in part I also received shocks where each individual pulse contained equal energy but was of a different duration (biphasic 3.3/11.1 ms; triphasic 2.0/3.2/9.2 ms). RESULTS: Triphasic shocks of equal duration pulses achieved higher success than biphasic shocks at delivered low energies: <40 J: 38 +/- 5% triphasic vs. 19 +/- 4% biphasic (p < 0.01); 40 to <50 J: 66 +/- 7% vs. 42 +/- 7% (p < 0.01); and 50 to <65 J: 78 +/- 4% vs. 54 +/- 5% (p < 0.05). Shocks of equal energy but different duration pulses achieved relatively poor success for both triphasic and biphasic waveforms. Shock-induced ventricular tachycardia (VT) and asystole occurred less often after triphasic shocks. CONCLUSIONS: Triphasic transthoracic shocks composed of equal duration pulses were superior to biphasic shocks for VF termination at low energies and caused less VT and asystole.

Does transesophageal echocardiographic demonstration of a patent foramen ovale in patients with a recent cerebral ischemic event change anticoagulation therapy?

BACKGROUND: Patent foramen ovale (PFO) is commonly demonstrated by transesophageal echocardiography (TEE) in patients with a recent transient ischemic attack or stroke. Our purpose was to determine how the TEE visualization of a PFO alters anticoagulation therapy. METHODS: We retrospectively identified 100 patients with transient ischemic attack or stroke referred for TEE; 50 had a PFO and 50 did not (control patients). RESULTS: Both groups were similar in regard to age, sex, the occurrence of transient ischemic attack versus stroke, and history of stroke. The PFO group had a higher incidence of a mobile interatrial septum, interatrial septal aneurysm, or both ( P < .001 by Fisher exact test). Both groups had similar pre-TEE aspirin, other antiplatelet, and warfarin use. After TEE, warfarin was instituted in 8 of 50 patients with PFO versus 2 of 50 in the control group ( P = .05) and aspirin use was discontinued in 9 of 50 patients with PFO versus 3 of 50 in the control group ( P = .12). CONCLUSION: The main effect of demonstrating a PFO by TEE after an ischemic cerebral event was the institution of warfarin; there was a trend toward discontinuing aspirin.

Effect of hypothermia on transthoracic defibrillation in a swine model.

BACKGROUND: Induced hypothermia (H) appears a promising intervention to protect the heart and brain after resuscitation from cardiac arrest. However, the influence of H on transthoracic defibrillation energy requirements is not well documented. METHODS: In 39 swine (21.4+/-1.3(S.E.) kg) hypothermia was induced by surrounding the head, thorax and abdomen with ice. The swine were divided into four groups: (1) normothermia (N) followed by severe H (30 degrees C) (n=10), (2) severe H followed by N (n=10), (3) N followed by moderate H (33 degrees C) (n=10) and (4) moderate H followed by N (n=9). After 30s of electrically induced ventricular fibrillation (VF), the swine were defibrillated (biphasic waveform) at energies of 20J, 30J, 50J and 100J in random order in both N and H conditions. RESULTS: For pigs in Group 1 (N followed by severe H), shock success in terminating VF was higher during hypothermia (odds ratio 4.09 (95% CI: 2.21, 5.58; p<0.0001), despite the fact that impedance rose from 39+/-3Omega (N) to 42+/-3Omega (H) (p<0.001) and current fell from 22+/-8 (N) to 21+/-7A (H) (p<0.001). There were no significant differences in the shock success between N and H for the other groups. Post-defibrillation ventricular asystole occurred less often during hypothermia compared to normothermia (p=0.0002). CONCLUSION: Severe H facilitated transthoracic defibrillation in this swine model. Since impedance rose and current fell during H, the improved shock success must be due to a hypothermia-induced change in the mechanical or electrophysiologic properties of the myocardium. Moderate hypothermia did not alter the energy requirement for defibrillation.

Effect of nitric oxide synthase modulation on resuscitation success in a swine ventricular fibrillation cardiac arrest model.

BACKGROUND: We have demonstrated previously that the nitric oxide synthase (NOS) inhibitor N(G)-nitro-L-arginine (L-NNA) decreases free radical generation and nitrosative injury via peroxynitrite formation after epicardial dc shocks. OBJECTIVE: Our purpose was to explore the effects of NOS inhibition and NOS donation on cardiopulmonary resuscitation (CPR) success after cardiac arrest of variable duration. We used the non-selective NOS inhibitor L-NNA and the selective neuronal NOS inhibitor ARR-17477, the NOS donor S-nitroso-N-acetylpenicillamine (SNAP) and the vasodilator Enalaprilat, which lowers arterial pressure via a non-NO mechanism. METHODS: Part I: 17 pigs undergoing 4 min supported (i.e. with closed-chest compression and ventilation) ventricular fibrillation (VF) were divided into two groups: a no-L-NNA group (n=8) receiving IV saline and an L-NNA group (n=9) receiving IV L-NNA (5 mg/kg) for 8 min before VF was induced. Part II: 35 pigs undergoing 6-8 min VF were randomized to three groups: a no-L-NNA group (n=13) receiving IV saline, an L-NNA group (n=11) receiving IV L-NNA (5 mg/kg) and an ARR17477 group (n=11) receiving IV ARR17477 (5 mg/kg) before VF. All animals in Part II underwent unsupported VF (no chest compression or ventilation) for 6 min (n=13) or 8 min (n=22); closed-chest compression, ventilation and epinephrine (adrenaline) were employed after defibrillation. Part III: 12 swine were divided into two groups: control (n=6) receiving saline and an LNNA group (n=6) receiving IV LNNA (5 mg/kg). Swine underwent 6 min unsupported VF and 2 min supported VF before defibrillation. Part IV: 25 animals were studied to determine the effect of the NO donor SNAP and the angiotensin-converting enzyme inhibitor Enalaprilat on coronary perfusion pressure (CPP). RESULTS: In Part I, after defibrillation, with continued ventilation, chest compression and epinephrine, 8/9 L-NNA pigs achieved ROSC versus 4/8 control pigs (p=0.11). After 60 s of CPR, 7/9 pigs in the L-NNA group achieved ROSC versus 2/8 pigs in the no-L-NNA group (p<0.05). Only 2/9 pigs receiving L-NNA required epinephrine (1 mg) after defibrillation, compared to 6/8 pigs requiring at least one dose of epinephrine in the no-L-NNA group (p<0.05). In Part II, there was no significant difference between L-NNA, ARR17477 and control pigs in ROSC. However, control pigs required 6.8+/-1.4S.E. mg epinephrine; L-NNA pigs and ARR17477 pigs required less epinephrine (3.7+/-0.7 and 3.0+/-0.3 mg, both p=0.01). Shorter chest compression was required in the L-NNA group (252+/-38 s, p<0.05) and in ARR17477 group (222+/-15 s, p<0.05) compared to the control group (405+/-77 s). In Part III, L-NNA infusion caused a significant increase in mean blood pressure at baseline, but did not change CPP throughout the experiment. In Part IV, there were no significant differences in the changes of mean blood pressure and CPP between SNAP and Enalaprilat group in all animals throughout the experiment. CONCLUSION: NOS inhibition pre-arrest did not improve survival, but did reduce requirements for epinephrine and closed-chest compression in a swine resuscitation model.

Surgical open-chest ventricular defibrillation: triphasic waveforms are superior to biphasic waveforms.

Triphasic shocks have been evaluated for endocardial defibrillation but not for open-chest epicardial defibrillation. The purpose of this study was to compare the efficacy and safety of biphasic versus triphasic shocks for epicardial defibrillation in a porcine model. Twenty-two adult swine (18-28 kg) were deeply anesthetized and intubated. After 30 seconds electrically induced VF, each pig received truncated exponential biphasic (7.2-ms positive pulse duration and 7.2-ms negative pulse duration, total waveform duration 14.4 ms) and triphasic (4.8/4.8/4.8 ms, total waveform duration 14.4 ms) epicardial shocks. Pigs in group 1 (n = 11) received epicardial biphasic and triphasic shocks from large hand held paddle electrodes (44.2 cm2); pigs in group 2 (n = 11) received shocks from small paddle electrodes (15.9 cm2). Shocks were given at five selected energy levels (3-30 J) in random sequence. Four shocks were delivered at each energy level to construct an energy versus percentage of success curve. In group 1 (large paddle electrodes), percentage of shock success was significantly higher for triphasic shocks at the energy levels of 3, 5, 10, and 20 J compared to biphasic shocks. In group 2 (small paddle electrodes), triphasic shocks yielded a significantly higher percentage of shock success than biphasic shocks at the energy levels of 5, 10, and 20 J). Shock induced ventricular tachycardia was similar for both waveforms; asystole was rare. For open-chest defibrillation, triphasic waveform shocks were superior to biphasic waveform shocks for VF termination at energy levels of 3-20 J and were as safe as biphasic shocks.