James Gamble

Cardiac resynchronization therapy delivered via a multipolar left ventricular lead is associated with reduced mortality and elimination of phrenic nerve stimulation: Long-term follow-up from a multicenter registry

Cardiac resynchronization therapy (CRT) using quadripolar left ventricular (LV) leads provides more pacing vectors compared to bipolar leads. This may avoid phrenic nerve stimulation (PNS) and allow optimal lead placement to maximize biventricular pacing. However, a long‐term improvement in patient outcome has yet to be demonstrated.

A novel diagnostic protocol to identify patients suitable for discharge after a single high-sensitivity troponin

Objective To establish whether a novel accelerated diagnostic protocol (ADP) for suspected acute coronary syndrome (ACS) could successfully identify low-risk patients suitable for discharge after a single high-sensitivity troponin T (hs-cTnT) taken at presentation to the emergency department. We also compared the diagnostic accuracy of this ADP with strategies using initial undetectable hs-cTnT. Methods This prospective observational study evaluated the ability of the Triage Rule-out Using high-Sensitivity Troponin (TRUST) ADP to identify low-risk patients with suspected ACS. The ADP incorporated a single presentation hs-cTnT of <14 ng/L, a non-ischaemic ECG and a modified Goldman risk score. Diagnostic performance of the ADP was compared with the detection limit cut-offs of hs-cTnT (<5 ng/L and <3 ng/L). The primary end point was fatal/non-fatal acute myocardial infarction (AMI) within 30 days. Results 960 participants were recruited, mean age 58.0 years, 80 (8.3%) had an AMI. The TRUST ADP classified 382 (39.8%) as low-risk with a sensitivity for identifying AMI of 98.8% (95% CI 92.5% to 99.9%). hs-cTnT detection limits (<5 ng/L and <3 ng/L) had a sensitivity of 100% (94.3 to 100) and 100% (94.4 to 100), respectively. The TRUST ADP identified more patients suitable for early discharge at 39.8% vs 29.3% (<5 ng/L) and 7.9% (<3 ng/L) (p<0.001) with a lower false-positive rate for AMI detection; specificity 43.3% (95% CI 42.7% to 43.4%) vs 32.0% (95% CI 31.5% to 32.0%) and 8.6% (95% CI 8.1% to 8.6%), respectively. Conclusions The TRUST ADP, which incorporates structured risk-assessment and a single presentation hs-cTnT blood draw, has potential to allow early discharge in 40% of patients with suspected ACS and has greater clinical utility than undetectable hs-cTnT strategies. Trial registration number ISRCTN No. 21109279.

Development of a technique for left ventricular endocardial pacing via puncture of the interventricular septum.

Background—Left ventricular (LV) pacing through the coronary sinus is the standard approach for cardiac resynchronization therapy. When this route is unavailable, the alternatives have major limitations. LV endocardial pacing through the interventriuclar septum may offer a simpler solution. We describe an initial case series to demonstrate technical feasibility and to describe our refinement of the puncture technique. Methods and Results—Ten patients with previous failed coronary sinus lead implant or with nonresponse to cardiac resynchronization therapy and a suboptimal LV lead position were selected. All patients were anticoagulated. Left ventriculography and coronary angiography were performed to identify LV borders and septal vessels. Subclavian vein access was used for a superior approach ventricular transseptal puncture under fluoroscopic guidance, using a steerable sheath and a standard transseptal needle, radiofrequency needle, or radiofrequency energy delivered through a guidewire. An active-fixation pacing lead was successfully delivered to the endocardial wall of the lateral LV in all patients (9 men; age, 62±10 years). LV lead implant procedure time shortened with experience. The use of radiofrequency energy delivered through a guidewire was the most effective technique. Mean threshold and R wave at implant were 0.8±0.3 V and 10.8±3.9 mV. At follow-up (mean, 8.7 months; minimum, 0; and maximum 19), thresholds were stable, and there were no thromboembolic events. Of 9 patients, 8 were classed as clinical responders (1 had inadequate follow-up to assess response). Conclusions—LV endocardial pacing through a ventricular septal puncture is a feasible approach for cardiac resynchronization therapy.

Endocardial left ventricular pacing for cardiac resynchronization: systematic review and meta-analysis.

Aims Endocardial left ventricular (LV) pacing for Cardiac Resynchronization Therapy has been proposed as an alternative to conventional LV lead placement via the coronary sinus. In order to assess the relative benefits and risks of this technique, we have performed a meta-analysis of published reports. Methods and results A systemic search was performed using online databases to identify studies of lead-based endocardial pacing. A random-effects meta-analysis was performed, to assess the rate of complications and clinical response (defined as ≥1 decrease in NYHA class). We selected 23 studies, including 384 patients. The trans-atrial septal technique was used in 20 studies, 1 used the trans-ventricular apical technique, and 2 used the trans-ventricular septal technique. Mean age was 66 years, male 66%, EF 26%, NYHA class 3.0. Procedural success rates were over 95% in all studies. Clinical response was reported by 16 studies for 262 patients, giving a response estimate of 82% (95% CI 71-89%). There was significant heterogeneity, and response in the only large study was 59%. Thromboembolic (TE) complications were reported by all studies, over 22 ±32 months follow up. The rate of stroke was 2.5 events per 100 patient years (95% CI 1.5-4.3), and TIA 2.6 (1.1-6.1). The mortality rate was 4.5 (1.5-13.6) per 100 patient years. Conclusion LV endocardial pacing appears to be a viable technique when conventional lead placement is not possible. Response rates were heterogeneous but comparable with conventional CRT. There is likely to be a small increase over expected rates of stroke, although included patients were high risk.

Letter by Gamble et al Regarding Article, “Inappropriate Shocks due to Subcutaneous Air in a Patient With a Subcutaneous Cardiac Defibrillator”

We were interested to read the report of Zipse et al,1 reporting inappropriate shocks delivered by a subcutaneous defibrillator because of undersensing, ascribed to entrapped subcutaneous air surrounding the distal sensing electrode. We encountered a similar phenomenon in a recent patient, although in our case it was because of air entrapment around the proximal sensing electrode. Our patient was a 22-year-old woman, receiving a subcutaneous defibrillator after idiopathic sustained fast polymorphic ventricular tachycardia. The procedure was performed using the 2-incision implantation technique …

022 A RAPID CHEST PAIN ASSESSMENT PATHWAY INCLUDING HIGH-SENSITIVITY TROPONIN T TESTING REDUCES LENGTH OF STAY

Introduction Patients admitted with chest pain represent a major part of the workload of all acute hospitals. Recently available high-sensitivity troponin assays provide an opportunity to accelerate assessment of these patients as they can safely exclude myocardial infarction (MI) much earlier after symptom onset, avoiding the need to wait for a 12 h sample. Both local and national priorities encourage increasing same-day discharge and reducing length of stay for low-risk patients with chest pain. Table 1 Group Baseline—original pathway Results—new pathway p Value Median length of stay (hours)—All diagnoses 28.2 27.3 0.07 Median length of stay (hours)—NCCP only 13.9 7.6 0.04 Proportion of same day discharges—All diagnoses 29% 36% 0.01 Proportion of same day discharges—NCCP only 49% 63% 0.01 Methods In March 2012 we introduced a new pathway to the Chest Pain Assessment Unit of a busy District General Hospital. This combines high-sensitivity troponin T (hsTnT) testing at admission and 6 h after symptom onset with formalised clinical risk-assessment using the ADP score, a modified and well-validated version of the TIMI risk score. The pathway was introduced as a pilot in working hours only. Data on 5271 admissions over the preceding 2 years were used as a baseline. Hospital episode statistics data was used to assess and compare length of stay (Mann-Whitney U test), the proportion of patients discharged on the same day and discharge diagnosis frequency (χ2 test) for all patients and for those with a final diagnosis of non-cardiac chest pain (NCCP). hsTnT results (normal level<14 ng/l) were compared with a 3-month sample of previously used point-of-care troponin T test results (normal level <50 ng/l). Results 331 patients were admitted and assessed using the new pathway with paired hsTnT testing between March and September 2012. 34% of patients had a discharge diagnosis of non-cardiac chest pain. There was a significant decrease in the number of low-risk patients unnecessarily given anti-platelet agents (50% to 14%, p<0.001). The changes provided a net cost benefit to the unit of approximately £14 000 per year, mainly driven by increased NHS Payment by Results tariffs for patients discharged on the same day. A large increase in the number of abnormal troponin results was seen but there was no significant change in the final rate of diagnosis of MI (16–17%, p=0.24%). Table 2 Troponin result Conventional TnT test hsTnT test p Value In normal range 76% 39% <0.001 Abnormal 24% 61% <0.001 Conclusions The introduction of a modified pathway for the assessment of chest pain including hsTnT testing was successful in significantly decreasing length of stay and increasing the proportion of same-day discharges, largely in those patients with non-cardiac chest pain. This enhanced patient satisfaction, improved bed availability and had positive financial implications for the unit. Significantly more troponin results were technically abnormal, although this did not result in an increased rate of MI diagnosis in this population, which is an interesting result requiring further investigation.

8 A Rapid Chest Pain Assessment Pathway including High-Sensitivity Troponin T Testing has a Limited Effect on Length of Stay

Patients admitted with chest pain represent a major part of the workload of all acute hospitals. High-sensitivity troponin assays provide an opportunity to accelerate assessment of these patients as they can exclude MI earlier after symptom onset, avoiding the need to wait for a 12-hour sample. Both local and national priorities encourage increasing same-day discharge and reducing length of stay for low-risk patients with chest pain, and accordingly these were the metrics we investigated. Methods We introduced a new pathway to the Chest Pain Assessment Unit of a busy District General Hospital. This combined high-sensitivity troponin T (hsTnT) testing at admission and 6 h after symptom onset with formalised clinical risk-assessment using the TIMI risk score combined with these serial troponin results. Hospital episode statistics data was used to identify and compare length of stay and discharge diagnosis. Median length of stay was compared using the Mann-Whitney U test, and the proportion of patients discharged on the same day with the Chi-squared test. Summary discharge diagnosis was available, and this was used to identify patients with diagnoses representing non-cardiac chest pain (NCCP). Results Data on 5271 admissions over the preceding 2 years were used as a baseline, and compared to the 3234 patients admitted between March 2012 and September 2013 inclusive, who were assessed using the new pathway with paired hsTnT testing. 878 (33%) of these patients had a discharge diagnosis that was classed as non-cardiac chest pain. Abstract 8 Table 1 Length of stay before and after changing pathway Group Baseline – Original Pathway Results – New Pathway P N (All diagnoses) 5271 3234 Median length of stay (hours) – All Diagnoses 30.7 26.8 <0.001 Proportion of same day discharges – All Diagnoses 23% 26% 0.01 N (NCCP only) 1622 878 Median length of stay (hours) – NCCP only 16.3 14.8 0.01 Proportion of same day discharges – NCCP only 41% 44% 0.12 Median length of stay was significantly reduced both in all admissions, and in those with a diagnosis identifiable as NCCP from discharge data. Same day discharges were also increased in both populations, although this increase was statistically significant only in the whole population. Abstract 8 Figure 1 Median length of stay each month. Vertical line denotes time of change in protocol The changes provided a net cost benefit to the unit of approximately £12500 per year, mainly driven by increased NHS Payment by Results tariffs for patients discharged on the same day, and despite increased costs for troponin testing. Conclusions The introduction of a modified pathway for the assessment of chest pain including hsTnT testing was successful in decreasing length of stay and increasing the proportion of same-day discharges. This had positive financial implications for the unit and improved the quality of care provided. The magnitude of the effect was smaller than might have been hoped for, suggesting that multiple other factors influence length of stay.