Transcoronary electrophysiological parameters in patients undergoing elective and acute coronary intervention.

INTRODUCTION: Percutaneous coronary intervention is performed routinely in the management of myocardial infarction with obstructive coronary disease, but intervention to arteries supplying nonviable myocardium may be harmful. It is important therefore to establish myocardial viability, and there is an unmet need in current clinical practice for real time viability assessment to aid in decision making. Transcoronary pacing to assess myocardial electrophysiological parameters may be a novel viability assessment technique which could be used in this regard. METHODS: Coronary intervention was carried out according to standard departmental procedure with standard equipment. An exchange length coronary guidewire was passed into both target and reference coronary vessels and an over-the-wire balloon or microcatheter was used to insulate the guidewire and allow electrophysiological parameters to be assessed. Readings were obtained from all major epicardial vessels and substantial branches. At each position, an intracoronary electrocardiogram was recorded, and R wave amplitude was measured. Transcoronary pacing was then performed to establish threshold and impedance for each myocardial segment. A viability cardiac MRI scan was performed for each patient. A standard segmental model was used to determine viability in each segment using an 'infarct score' based on degree of late gadolinium enhancement. Studies were reported blinded to the electrical parameters obtained from the coronary guidewire. The primary outcome was the relationship between pacing threshold and myocardial segment infarct score. Secondary outcomes included the relationship between segmental infarct score and R wave height, and between segmental infarct score and pacing impedance. Data were collected on the feasibility of studying the coronary segments as well as safety. RESULTS: Sixty-five patients presenting with stable coronary artery disease or acute coronary syndromes to Leeds General Infirmary between September 2019 and August 2021 were included in the study. Electrophysiological parameters from segments with an infarct score of zero were obtained, with wide variances seen, with no significant difference in impedance or threshold in any territory. There was a significant difference in sensitivity for segments in the right coronary artery territory for both elective and acute patients. This likely relates to reduced myocardial mass in these territories. No significant association between infarct score and sensitivity, impedance or threshold were seen. CONCLUSION: This study has established intracoronary electrophysiological parameters in both normal myocardium and areas of myocardial scar. No reliable association was seen between impedance, threshold or R wave amplitude and degree of myocardial viability, contrasting with prior findings from our group and others. More work is therefore required to fully understand the role of transcoronary pacing in this setting.

What training should psychiatrists have to interpret six- and 12-lead electrocardiograms?

To monitor for drug-related cardiac arrhythmias, psychiatrists regularly perform and interpret 12-lead (12L) and, increasingly often, six-lead (6L) electrocardiograms (ECGs). It is not known how training on this complex skill is updated or how well psychiatrists can interpret relevant arrhythmias on either device.We conducted an online survey and ECG interpretation test of cardiac rhythms relevant to psychiatrists.A total of 183 prescribers took part; 75% did not regularly update their ECG interpretation skills, and only 22% felt confident in interpreting ECGs. Most participants were able to recognise normal ECGs. For both 6L and 12L ECGs, the majority of participants were able to recognise abnormal ECGs, but fewer than 50% were able to correctly identify relevant arrhythmias (complete heart block and long QTc). A small number prescribed in the presence of potentially fatal arrhythmias. These findings suggest a need for mandatory ECG interpretation training to improve safe prescribing practice.

Reverse RAMP (REVRAMP) pacing: A novel anti tachycardia pacing technique.

Anti-tachycardia pacing (ATP) is frequently used to terminate ventricular tachycardia (VT), however it is not always successful and may accelerate VT requiring defibrillation. REVRAMP is a novel concept of ATP that involves delivering pacing at a faster rate than VT, but instead of abruptly terminating pacing after eight beats, pacing is gradually slowed until VT continues or normal rhythm is restored. In a pilot study we show that REVRAMP can restore normal rhythm, and that if REVRAMP is unsuccessful, VT is not accelerated.

Clinical validation and evaluation of a novel six-lead handheld electrocardiogram recorder compared to the 12-lead electrocardiogram in unselected cardiology patients (EVALECG Cardio).

Aims: Handheld electrocardiogram (ECG) monitors are increasingly used by both healthcare workers and patients to diagnose cardiac arrhythmias. There is a lack of studies validating the use of handheld devices against the standard 12-lead ECG. The Kardia 6L is a novel handheld ECG monitor which can produce a 6-lead ECG. In this study, we compare the 6L ECG against the 12-lead ECG. Methods and results: A prospective study consisting of unselected cardiac inpatients and outpatients at Leeds Teaching Hospital NHS Trust. All participants had a 12- and 6-lead ECGs. All ECG parameters were analysed by using a standard method template for consistency between independent observers. Electrocardiograms from the recorders were compared by the following statistical methods: linear regression, Bland-Altman, receiver operator curve, and kappa analysis. There were 1015 patients recruited. The mean differences between recorders were small for PR, QRS, cardiac axis, with receiver operator analysis area under the curve (AUC) of >80%. Mean differences for QT and QTc (between recorders) were also small, with AUCs for QT leads of >75% and AUCs for QTc leads of >60%. Key findings from Bland-Altman analysis demonstrate overall an acceptable agreement with few outliers instances (<6%, Bland-Altman analysis). Conclusion: Several parameters recorded by the Kardia 6L (QT interval in all six leads, rhythm detection, PR interval, QRS duration, and cardiac axis) perform closely to the gold standard 12-lead ECG. However, that consistency weakens for left ventricular hypertrophy, QRS amplitudes (Lead I and AVL), and ischaemic changes.

Transcoronary pacing to assess myocardial viability prior to percutaneous coronary intervention: Pilot study to assess feasibility.

BACKGROUND: The assessment of myocardial viability is crucial before percutaneous coronary intervention (PCI) is carried out to ensure that the patient will gain benefit. Trans-coronary pacing (TCP) has previously been used to pace myocardium but may also provide information on myocardial viability. METHODS: Patients with a single, significant coronary stenosis requiring PCI were recruited. They underwent a cardiac MRI to assess myocardial viability. Prior to PCI, a coronary guidewire was used to measure pacing threshold, impedance, and R-wave amplitude in different myocardial segments to determine any association between the electrical parameters and myocardial viability. RESULTS: Eight patients were recruited and six patients underwent intervention. Pacing sensitivity did not demonstrate statistically significant differences between normal and scarred myocardium. Impedance demonstrated a mean of 304.8 ± 74.0 Ω in normal myocardium (NM), 244.1 ± 66.6 Ω in <50% myocardial scar (MS), and 222.3 ± 33.8 Ω in ≥50% MS. Pacing threshold demonstrated a mean of 1.960 ± 1.226 V in NM, 5.009 ± 2.773 V in <50% MS, and 3.950 ± 0.883 V in ≥50% MS. For both impedance and threshold, there was a significant difference among the groups (P = 0.12 and P = 0.002, respectively), and post hoc Tukey's pairwise comparison demonstrated significant differences between NM and scarred myocardium. No significant differences were found between <50% MS and ≥50% MS. CONCLUSIONS: Impedance and pacing threshold, measured during TCP, can be used to differentiate between normal myocardium and scarred myocardium. Further research is needed to determine whether TCP can discriminate between viable and nonviable myocardium.

Low value of simple echocardiographic indices of ventricular dyssynchrony in predicting the response to cardiac resynchronization therapy.

AIMS: A recent study suggested that no single echocardiographic index of cardiac dyssynchrony can reliably identify candidates for cardiac resynchronization therapy (CRT). We examined the value of three simple echocardiographic indices for predicting the 6-month clinical and echocardiographic responses to CRT. METHODS AND RESULTS: We analysed data from 75 CRT-D system recipients. Standard echocardiography was used to measure aortic pre-ejection delay (APED), interventricular mechanical delay (IVMD), and delayed activation of the left ventricular (LV) infero-lateral wall (OVERLAP). Clinical responders were defined as patients who had an improved status, based on rehospitalization for heart failure, NYHA class, and peak oxygen consumption. Echocardiographic responders had a > or =10% decrease in LV end-systolic volume. During the study, one patient died and five were lost to follow-up. Of the remaining 69 analysable patients, 50 (72.5%) were classed as clinical responders and 41 (59.4%) as echocardiographic responders to CRT. Before CRT implantation, APED, IVMD, and OVERLAP were similar in responders and non-responders. The value of these indices of dyssynchrony as single or combined predictors of the clinical or echocardiographic response to CRT was low, with sensitivities ranging between 4 and 63%, and specificities between 37 and 100%. CONCLUSION: Simple echocardiographic indices of dyssynchrony were poor predictors of response to CRT.

Fragmentation and embolization of pacemaker leads as a complication of lead extraction.

Fragmentation and embolization of permanent pacemaker (PPM) leads into the pulmonary circulation is a rare complication of lead extraction procedures. We present two cases of lead tip embolization in patients undergoing lead extraction. The literature pertaining to the incidence and management of lead fragmentation and embolization is discussed.

Unexpected long-term survival without evidence of disease after salvage chemotherapy for recurrent metastatic cervical cancer: a case series.

BACKGROUND: The prognosis of recurrent metastatic cervical cancer is extremely poor. Platinum-based palliative chemotherapy constitutes the mainstay of treatment. Cure is extremely rare. CASE: We present 3 cases of recurrent metastatic cervical cancer in which the patients remain disease-free many years after completing salvage chemotherapy and surgery. The patients remain with no evidence of disease at 6, 7, and 13 years, respectively, following recurrence. CONCLUSION: In rare cases, an unexpected complete clinical remission and long-term survival without evidence of disease may be achieved in patients with recurrent metastatic cervical cancer treated with multimodal therapy.

Prevention of inappropriate shocks in ICD recipients: a review of 10,000 tachycardia episodes.

BACKGROUND: The efficacy of dual-chamber ICD arrhythmia classification algorithms is crucial to prevent inappropriate shocks. We report our experience from a meta-analysis of five prospective clinical studies with inclusion phases ranging between 1997 and 2003. METHODS: Dual-chamber ICD using standard dual-chamber arrhythmia classification algorithms were implanted in 802 patients (mean age = 64 +/- 11 years, 88% men) in 74 medical centers. The ICD indication was secondary prevention in 95% of patients. Supraventricular tachyarrhythmias (SVT) were previously documented in 26% of patients. All spontaneous tachyarrhythmic events documented by the device memories were analyzed by a adjudicating committee. The episodes lasting > 12 seconds and/or treated by the ICD were analyzed. RESULTS: Over a mean follow-up of 302 +/- 113 days, 9,690 events were reported. Mean heart rate at the time of events was 131 +/- 45 bpm (100-430). Events were classified as oversensing in 1.4%, sinus tachycardia (ST) in 66%, SVT in 13%, slow (< 150 bpm) ventricular tachycardia (VT) in 8.7%, and VT or ventricular fibrillation (VF) in 10.3%. The sensitivity of slow VT detection was 94%, and of VT/VF detection 99.3%. The specificity of sinus rhythm/ST/SVT recognition was 94%, positive predictive value 79.3%, and negative predictive value 99.2%. A total of 1,918 episodes were treated in 330 patients: 1,472 appropriately in 213, and 446 inappropriately in 117 (15% of the overall population) patients. Only 62 episodes were inappropriately treated by shocks in 40 patients, representing 5% of the overall population. CONCLUSIONS: In this conventional ICD population, the overall specificity of standard dual-chamber arrhythmia detection settings reached 94%. This feature allows efficient detection of fast as well as slow VT events with a very low rate of inappropriate shocks.

Incidence and clinical relevance of slow ventricular tachycardia in implantable cardioverter-defibrillator recipients: an international multicenter prospective study.

BACKGROUND: This study aims to assess the incidence and clinical relevance of slow ventricular tachycardia (VT) and the effectiveness and/or deleterious effects of antitachycardia pacing in slow VT in implantable cardioverter-defibrillator recipients. METHODS AND RESULTS: This multicenter prospective randomized study included 374 patients (326 men) without prior history of slow VT (<148 bpm) implanted with a dual-chamber implantable cardioverter-defibrillator. Patients had a 3-zone detection configuration: a slow VT zone (101 to 148 bpm), a conventional VT zone (>148 bpm), and a ventricular fibrillation zone. Patients were randomized to a treatment group (n=183) with therapy activated in the slow VT zone or a monitoring group (n=191) with no therapy in the slow VT zone. During follow-up (11 months), 449 slow VTs occurred in 114 patients (30.5% slow VT incidence); 181 VTs (54 patients) occurred in the monitoring group; 3 were readmitted to the hospital; and lightheadedness and palpitations occurred in 4 and 250 (60 patients) in the treatment group treated by antitachycardia pacing (89.8% success rate) and shock delivery (n=2). There were 10 crossovers from the monitoring to treatment group and 3 crossovers from the treatment to monitoring group (P=0.09). Quality of life scores were not different between groups. CONCLUSIONS: Slow VT incidence (<150 bpm) is high (30%) in implantable cardioverter-defibrillator recipients without prior history of slow VT, has limited clinical relevance, and is efficiently and safely terminated by antitachycardia pacing.

Enhanced specificity of a dual chamber ICD arrhythmia detection algorithm by rate stability criteria.

Inappropriate therapy remains an important limitation of implantable cardioverter defibrillators (ICD). PARAD+ was developed to increase the specificity conferred by the original PARAD detection algorithm in the detection of atrial fibrillation (AF). To compare the performances of the two different algorithms, we retrospectively analyzed all spontaneous and sustained episodes of AF and ventricular tachycardia (VT) documented by state-of-the-art ICDs programmed with PARAD or PARAD+ at the physicians' discretion. The results were stratified according to tachycardia rates <150 versus > or =150 beats/min. The study included 329 men and 48 women (64 +/- 10 years of age). PARAD was programmed in 263, and PARAD+ in 84 devices. During a mean follow-up of 11 +/- 3 months, 1,019 VT and 315 AF episodes were documented among 338 devices. For tachycardias with ventricular rates <150 beats/min, the sensitivity of PARAD versus PARAD+ was 96% versus 99% (NS), specificity 80% versus 93% (P < 0.002), positive predictive value (PPV) 94% versus 91% (NS), and negative predictive value (NPV) 86% versus 99% (P < 0.0001). In contrast, in the fast VT zone, the specificity and PPV of PARAD (95% versus 84% and 100% versus 96%) were higher than those of PARAD+ (NS, P < 0.001). Among 23 AF episodes treated in 16 patients, 3 episodes triggered an inappropriate shock in 3 patients, all in the PARAD population. PARAD+ significantly increased the ICD algorithm diagnostic specificity and NPV for AF in the slow VT zone without compromising patient safety.