Cardiac biomarkers of acute coronary syndrome: from history to high-sensitivity cardiac troponin

The role of cardiac troponins as diagnostic biomarkers of myocardial injury in the context of acute coronary syndrome (ACS) is well established. Since the initial 1st-generation assays, 5th-generation high-sensitivity cardiac troponin (hs-cTn) assays have been developed, and are now widely used. However, its clinical adoption preceded guidelines and even best practice evidence. This review summarizes the history of cardiac biomarkers with particular emphasis on hs-cTn. We aim to provide insights into using hs-cTn as a quantitative marker of cardiomyocyte injury to help in the differential diagnosis of coronary versus non-coronary cardiac diseases. We also review the recent evidence and guidelines of using hs-cTn in suspected ACS

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 &gt;_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. Conclusions 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.</p

Endocardial left ventricular pacing across the interventricular septum for cardiac resynchronization therapy: clinical results of a pilot study

Background Cardiac resynchronization therapy (CRT) is an effective treatment for selected patients with heart failure, but it can be limited by the inability to place the left ventricular (LV) lead via the coronary sinus. Objective The purpose of this study was to develop an alternative approach, placing the LV lead endocardially via an interventricular septal puncture, and to assess the feasibility and safety of this technique. Methods All patients were anticoagulated with warfarin (international normalized ratio 2.5–3.5). A superior approach ventricular transseptal puncture using radiofrequency energy was performed. An active fixation pacing lead was delivered to the mapped site of latest electrical activation on the endocardial LV. Results Twenty patients were recruited, 15 with failed transvenous LV lead placement and 5 nonresponders to CRT. Mean (± SD) age was 67 ± 12, with 80% male, QRS duration 157 ± 14 ms, ischemic etiology 45%, New York Heart Association functional class 2.9 ± 0.4, and LV ejection fraction 28% ± 7%. The procedure was successful in all, with no serious complications. Clinical composite score improved at 6 months in 65% and worsened in 35%. LV ejection fraction improved &gt;5% in 88%, from 28% ± 7% to 41% ± 9%. Six-minute walking distance improved &gt;10% in 64%, from 248 ± 125 m to 316 ± 109 m. One patient suffered a lacunar ischemic stroke after 5 months with partial neurological recovery, associated with labile international normalized ratios. After 2.0 ± 1.0 years of follow-up, 3 patients died (2 pneumonia, 1 heart failure), and 2 patients suffered transient ischemic attacks. Conclusion LV endocardial pacing via interventricular septal puncture in patients for whom standard CRT is not possible is similarly effective and durable, with significant but potentially acceptable risks.</p

Procedural success of left ventricular lead placement for cardiac resynchronization therapy: A meta-analysis

Objectives The goal of this study was to assess the contemporary and historical success rates of transvenous left ventricular (LV) lead placement for cardiac resynchronization therapy (CRT), their change over time, and the reasons for failure. Background In selected patients, CRT improves morbidity and mortality, but the placement of the LV lead can be technically challenging. Methods A literature search was used to identify all studies reporting success rates of LV lead placement for CRT via the coronary sinus (CS) route. A total of 164 studies were identified, and a meta-analysis was performed. Results The studies included 29,503 patients: 74% (95% confidence interval [CI]: 72% to 76%) were male; their mean age was 66 years (95% CI: 65 to 67); their mean New York Heart Association functional class was 2.8 (95% CI: 2.7 to 2.9); the mean LV ejection fraction was 26% (95% CI: 25% to 28%); and the mean QRS duration was 155 ms (95% CI: 150 to 160). The overall rate of failure of implantation of an LV lead was 3.6% (95% CI: 3.1 to 4.3). The rate of failure in studies commencing before 2005 was 5.4% (95% CI: 4.4% to 6.5%), and from 2005 onward it was 2.4% (95% CI: 1.9% to 3.1%; p &lt; 0.001). Causes of failure (reported for 39% of failures) also changed over time. Failure to cannulate and navigate the CS decreased from 53% to 30% (p = 0.01), and the absence of any suitable, acceptable vein increased from 39% to 64% (p = 0.007). The proportion of leads in a lateral or posterolateral final position (reported for 26% of leads) increased from 66% to 82% (p = 0.004). Conclusions The reported rate of failure to place an LV lead via the CS has decreased steadily over time. A greater proportion of failures in recent studies are due to coronary venous anatomy that is unsuitable for this technique

Endocardial left ventricular pacing across the interventricular septum for cardiac resynchronization therapy: clinical results of a pilot study

Background Cardiac resynchronization therapy (CRT) is an effective treatment for selected patients with heart failure, but it can be limited by the inability to place the left ventricular (LV) lead via the coronary sinus. Objective The purpose of this study was to develop an alternative approach, placing the LV lead endocardially via an interventricular septal puncture, and to assess the feasibility and safety of this technique. Methods All patients were anticoagulated with warfarin (international normalized ratio 2.5–3.5). A superior approach ventricular transseptal puncture using radiofrequency energy was performed. An active fixation pacing lead was delivered to the mapped site of latest electrical activation on the endocardial LV. Results Twenty patients were recruited, 15 with failed transvenous LV lead placement and 5 nonresponders to CRT. Mean (± SD) age was 67 ± 12, with 80% male, QRS duration 157 ± 14 ms, ischemic etiology 45%, New York Heart Association functional class 2.9 ± 0.4, and LV ejection fraction 28% ± 7%. The procedure was successful in all, with no serious complications. Clinical composite score improved at 6 months in 65% and worsened in 35%. LV ejection fraction improved >5% in 88%, from 28% ± 7% to 41% ± 9%. Six-minute walking distance improved >10% in 64%, from 248 ± 125 m to 316 ± 109 m. One patient suffered a lacunar ischemic stroke after 5 months with partial neurological recovery, associated with labile international normalized ratios. After 2.0 ± 1.0 years of follow-up, 3 patients died (2 pneumonia, 1 heart failure), and 2 patients suffered transient ischemic attacks. Conclusion LV endocardial pacing via interventricular septal puncture in patients for whom standard CRT is not possible is similarly effective and durable, with significant but potentially acceptable risks