Worldwide survey on implantation of and outcomes for conduction system pacing with His bundle and left bundle branch area pacing leads.

BACKGROUND: Adoption and outcomes for conduction system pacing (CSP), which includes His bundle pacing (HBP) or left bundle branch area pacing (LBBAP), in real-world settings are incompletely understood. We sought to describe real-world adoption of CSP lead implantation and subsequent outcomes. METHODS: We performed an online cross-sectional survey on the implantation and outcomes associated with CSP, between November 15, 2020, and February 15, 2021. We described survey responses and reported HBP and LBBAP outcomes for bradycardia pacing and cardiac resynchronization CRT indications, separately. RESULTS: The analysis cohort included 140 institutions, located on 5 continents, who contributed data to the worldwide survey on CSP. Of these, 127 institutions (90.7%) reported experience implanting CSP leads. CSP and overall device implantation volumes were reported by 84 institutions. In 2019, the median proportion of device implants with CSP, HBP, and/or LBBAP leads attempted were 4.4% (interquartile range [IQR], 1.9-12.5%; range, 0.4-100%), 3.3% (IQR, 1.3-7.1%; range, 0.2-87.0%), and 2.5% (IQR, 0.5-24.0%; range, 0.1-55.6%), respectively. For bradycardia pacing indications, HBP leads, as compared to LBBAP leads, had higher reported implant threshold (median [IQR]: 1.5 V [1.3-2.0 V] vs 0.8 V [0.6-1.0 V], p = 0.0008) and lower ventricular sensing (median [IQR]: 4.0 mV [3.0-5.0 mV] vs. 10.0 mV [7.0-12.0 mV], p < 0.0001). CONCLUSION: In conclusion, CSP lead implantation has been broadly adopted but has yet to become the default approach at most surveyed institutions. As the indications and data for CSP continue to evolve, strategies to educate and promote CSP lead implantation at institutions without CSP lead implantation experience would be necessary.

Ventricular tachycardia or supraventricular tachycardia?

It shows a pseudo -A-V-V-A response after stopping overdrive atrial pacing of a broad complex tachycardia.

Long-term longevity and clinical outcomes of Linox S/SD implantable cardioverter-defibrillator leads: a single-center experience.

PURPOSE: Since the introduction of the Biotronik Linox S/SD leads in 2006, there have been multiple reports of premature lead failure. The purpose of this study was to investigate the longevity of the Linox S/SD leads and to identify the possible predictors of lead failure in a single tertiary implant center. METHODS: We retrospectively reviewed patients who underwent implantation of Linox S/SD leads or Sorin Vigila 1CR/2CR leads (the same Linox S/SD leads marketed by Sorin) at our center. The cumulative lead survival was estimated using the Kaplan-Meier curve, and variables associated with lead failure were assessed by Cox proportional hazard model. RESULTS: A total of 187 patients (154 (82%) male) underwent Linox S/SD or Vigila 1CR/2CR implantation between 2007 and 2013. During follow-up with a median time of 75 months, nine lead failures were identified (4.8%). The mean and median times from lead implantation to lead failure were 70.7 ± 21 months and 64 (45-111) months, respectively. The cumulative survival probability for the Linox S/SD at 5 years was 97.1% and at 12 years was 90.3%. Non-physiological high-rate sensing was the most common type of lead failure in patients. In two-thirds of these patients, this led to inappropriate shock. We did not find any significant relationships between patients' clinical and procedural characteristics and lead failure. CONCLUSIONS: At our center, the 5-year lead survival of the Linox S/SD has been better than reports from other centers. The majority of lead failures presented as non-physiological high-rate sensing with subsequent inappropriate therapy.

Junctional ectopic tachycardia (JET).

Junctional ectopic tachycardia (JET) is a tachyarrhythmia arising from the atrioventricular node and His bundle area. Enhanced normal automaticity has been postulated as the mechanism of JET in the majority of patients. It is more common in children and can be seen as congenital or in postoperative settings. It is often a narrow complex tachycardia but can present as a wide complex tachycardia as a result of aberrant conduction. Its differentiation from other arrhythmias especially atrioventricular nodal reentrant tachycardia (AVNRT) can be challenging. Medical treatment of JET is difficult, and catheter ablation remains the mainstay of treatment in refractory cases with a high risk of atrioventricular block and recurrence.

Micra implantation in a patient with transposition of great arteries.

We describe a 56-year-old male with transposition of the great arteries and Mustard repair, superior vena cava obstruction, atrial fibrillation, and progressive deterioration of his epicardial lead performance. We were successful in deploying of Micra (Medtronic, Minneapolis, MN, USA) at the septo-apical area of his nonsystemic ventricle in a stable position with satisfactory pacing and sensing thresholds.

Pacemaker-mediated arrhythmias.

Pacemakers can be directly involved in initiating or sustaining different forms of arrhythmia. These can cause symptoms such as dyspnea, palpitations, and decompensated heart failure. Early detection of these arrhythmias and optimal pacemaker programming is pivotal. The aim of this review article is to summarize the different types of pacemaker-mediated arrhythmias, their predisposing factors, and mechanisms of prevention or termination.

Long-term pacemaker dependency and impact of pacing on mortality following transcatheter aortic valve replacement with the LOTUS valve.

OBJECTIVES: To determine permanent pacemaker (PPM) dependency following transcatheter aortic valve replacement (TAVR) with the Lotus™ valve system (Boston Scientific), and the impact of PPM implantation on long-term morbidity and mortality. BACKGROUND: Conduction abnormalities are among the most common complications following TAVR. Limited studies have assessed pacing dependency following TAVR. METHODS: Consecutive patients (n = 166) with severe aortic stenosis who underwent TAVR with the Lotus valve system were prospectively recruited from a single-center. PPMs were implanted according to standard clinical criteria. Patients were followed in-hospital and at 1, 3, 6, and 12 months to determine pacemaker dependency and clinical outcomes. RESULTS: Fourteen patients with a pre-existing PPM (8%) were excluded with the remaining 152 patients aged 83.6 ± 5.6 years and 46% male. PPMs were implanted 3.8 ± 4 days post-TAVR in 38/152 patients (25%). Indication for PPM was complete heart block in 29 (76%) of patients. At 30-day and one-year follow up, 57% and 38% of patients were pacemaker dependent, respectively. The mean ventricular pacing percentage decreased in the first three months after PPM implantation and remained relatively stable after that. CONCLUSION: Only 38% of Lotus recipients who require a PPM following TAVR with the Lotus valve remain pacing dependent at one year.

Loss of cardiac resynchronization therapy in a patient with a biventricular implantable cardioverter-defibrillator.

Here, we discuss the case of a man with a history of ischemic cardiomyopathy and cardiac resynchronization therapy defibrillator implantation, who presented to emergency department with decompensated heart failure due to the loss of resynchronization therapy. The reason for the malfunction was left ventricle upper rate interval lock-in due to inappropriate programming of the device.

Aborted sudden cardiac death in a patient with implantable loop recorder.

We discuss a 46-year-old man with history of hypertension and inferior wall myocardial infarction and mild left ventricular dysfunction who presented with aborted sudden cardiac death due to episodes of ventricular tachyarrhythmia detected by a Reveal-LINQ which had been implanted one year prior to presentation.

Changes in Heart Rate Variability Parameters after Elective Percutaneous Coronary Intervention.

BACKGROUND: Patients with chronic stable angina often have a state of sympathetic hyperactivity. It is considered associated with myocardial ischemia and disappears after ischemia elimination. The aim of this study was to investigate the changes in heart rate variability parameters, a noninvasive technique for the evaluation of the autonomic nervous system activity, after successful revascularization in these patients to evaluate this theory. METHODS: The patients were enrolled among those who underwent successful percutaneous coronary intervention. Short-term heart rate variability analyses of all the patients were obtained, and time-domain indices (standard deviation of normal-to-normal intervals [SDNN], standard deviation of differences of successive R-R intervals [SDSD], root-mean square differences of successive R-R intervals [rMSSD], percentage of R-R intervals differing > 10 ms from the preceding one [PNN10], percentage of R-R intervals differing > 20 ms from the preceding one [PNN20], percentage of R-R intervals differing > 30 ms from the preceding one [PNN30], percentage of R-R intervals differing > 40 ms from the preceding one [PNN40], percentage of R-R intervals differing > 50 ms from the preceding one [PNN50], percentage of R-R intervals differing > 60 ms from the preceding one [PNN60], and percentage of R-R intervals differing > 70 ms from the preceding one [PNN70]) were analyzed. All the measurements were made before and after percutaneous coronary intervention. RESULTS: This study included 64 patients, comprising 27 men and 37 women at a mean age of 56.8 ± 9.1 years. There was a significant difference only between pre- and post-revascularization SDNN (27.5 ± 19.72 vs. 41 ± 41.4; p value = 0.013). The other parameters showed no significant differences after successful coronary intervention. Conclusion : Our data indicate that the increase in SDNN in patients with stable angina pectoris undergoing percutaneous coronary intervention seems to be prominent.

Diffuse inverted T waves in a young man with structurally normal heart: a case report.

We discuss a young man with episodes of chest pain and dyspnea accompanied with transient T-wave inversion in precordial and inferior leads that repeated several times. Cardiovascular evaluation did not disclose any structural abnormality. Memory T wave following episodes of idiopathic left septal ventricular tachycardia was the reason of these changes and did not repeat after arrhythmia ablation.

Randomized Prospective Comparison of Two Protocols for Head-up Tilt Testing in Patients with Normal Heart and Recurrent Unexplained Syncope.

BACKGROUND: This randomized study was aimed to compare the diagnostic value of two head-up tilt testing protocols using sublingual nitroglycerin for provocation in patients with recurrent unexplained syncope and normal heart. METHODS: The patients with normal findings in physical examination, electrocardiography and echocardiography were randomly submitted to one of upright tilt test protocols. The only difference between two protocols was that nitroglycerin was administered after a five minute resting phase in supine position during protocol B. We also considered eighty normal persons as the control group. RESULTS: Out of 290 patients that underwent tilt testing, 132 patients were in group A versus 158 patients in group B. Both groups had an identical distribution of clinical characteristics. Tilt test was positive in 79 patients in group A (25 in passive phase, 54 in active phase) versus 96 patients in group B (43 in passive phase, 53 in active phase). There was no significant difference between results in two groups (P value= 0.127). Forty cases were tested with protocol A and forty underwent tilt testing with protocol B. Tilt test was positive in 4 cases with protocol A versus 3 cases in protocol B. The positive rates of tilt testing with protocol A was 60% while it was 61% in protocol B. The specificity of testing with protocol A was 90% and it was 92.5% in protocol B. CONCLUSIONS: According to our data, adding a period of rest and returning to supine position before nitroglycerin administration had no additional diagnostic yield.

The prevalence and prognostic role of vitamin D deficiency in patients with acute coronary syndrome: a single centre study in South-West of Iran.

BACKGROUND: The objectives of this study were estimating the prevalence of vitamin D deficiency in patients with acute coronary syndrome comparing with normal people and evaluating the relationship between vitamin D deficiency and short-term mortality in these patients. METHODS: We considered 106 patients with non-ST elevation myocardial infarction and high-risk unstable angina and 110 patients with ST elevation myocardial infarction as group A. The control group (group B) consisted of 120 individuals without any known cardiovascular diseases or systemic disease. We measured serum 25-hydroxyvitamin D in all cases and classified them according to their serum 25-hydroxyvitamin D levels. Sufficient vitamin D level was considered ≥30 ng/ml. We followed the patients for 30 days after index admission. RESULTS: The prevalence of hypovitaminosis D in group A was much higher than group B. In group A, 72% of patients had serum 25-hydroxyvitamin D level of 20 ng/ml or less. This percentage was only 27.4% in control group. We did not find any significant relationship between vitamin D deficiency and short-term mortality in patients with acute coronary syndrome. CONCLUSION: Our data suggest that vitamin D deficiency was present in most of patients admitted with acute coronary syndrome in Ahvaz.

Chest pain units: A necessity or only a name to encourage patients.

BACKGROUND: Acute chest pain is a common symptom among patients presenting to emergency wards. Identification and admission of patients with real acute coronary syndrome and preventing the hospitalization of people with false diagnosis of coronary syndrome are the most important tasks in emergency wards. The purpose of this study was to investigate the usefulness of designing a special chest pain unit in emergency department of Imam Khomeini Hospital (Ahvaz, Iran). METHODS: The patients with markers of ongoing cardiac ischemia underwent selective coronary angiography. The chest pain unit protocol was applied to selected patients with no definite evidence of acute coronary syndrome or alternative pathology. The protocol consisted of twelve hours of observation and serial 12-lead electrocardiography, transthoracic echocardiography, and biochemical testing followed by an exercise treadmill test. We compared the number of patients who were discharged after work up, discharged themselves against medical advice, admitted at coronary care unit (CCU), underwent invasive procedures or died between 2007 and 2010. RESULTS: During 2010, 43% of patients were discharged after evaluation in the chest pain unit. In 2007 however, 26% were discharged following traditional assessments. The admission rate increased from 23% in 2007 to 36% in 2010. The percentage of patients who discharged themselves against medical advice decreased from 37% in 2007 to 14% in 2010. There was not a statistically significant difference between mortality rates in 2007 and 2010. CONCLUSION: Providing a special chest pain unit in emergency ward in our condition is helpful. It reduces unnecessary admissions and improves patient satisfaction.

The prognostic role of serum uric acid level in patients with acute ST elevation myocardial infarction.

OBJECTIVES: The role of uric acid as a prognostic factor in patients with acute ST elevation myocardial infarction is controversial. The purpose of this study was to demonstrate the relationship between serum uric acid level and mortality during admission period and 30-day period after admission. METHODS: We assessed the relation between serum uric acid level and in-hospital and short-term mortality rates in 184 patients admitted with acute ST elevation myocardial infarction. We divided the patients according to their gender and uric acid level measured on admission into four groups: group A1: men with uric acid ⩽7 mg/dl versus group B1: men with uric acid >7 mg/dl and group A2: women with uric acid ⩽5.6 mg/dl versus group B2: women with uric acid >5.6 mg/dl. The patients were followed for 30 days after admission. RESULTS: In-hospital mortality rate in group B1 was higher than group A1 [P value: 0.011, Relative risk: 13.33 (95% confidence interval: 1.55-114.7)]. Short-term all-cause mortality was significantly higher in group B1 patients [P value: 0.037, Relative risk: 3.3 (95% confidence interval: 1.02-10.64)]. Multivariate logistic regression analysis of data showed an odds ratio of 15.23 for in-hospital mortality and odds ratio of 3.76 for short-term mortality in male hyperuricemic patients. CONCLUSIONS: Our data suggest that in the acute phase of ST elevation myocardial infarction, uric acid has a prognostic role for in-hospital and short-term (30-day) mortality in men.

Comparison of alendronate and pamidronate on bone loss in kidney transplant patients for the first 6 months of transplantation.

INTRODUCTION: Osteoporosis develops and progresses in a considerable number of kidney transplant patients. Bisphosphonates, which are used for prevention and treatment of osteoporosis, may accentuate gasterointestinal complications and lead to more nonadherence to treatment. This randomized clinical trial was conducted to compare the effect of pamidronate versus alendronate on early bone mineral density changes in kidney transplant patients. MATERIALS AND METHODS: Forty patients (27 men and 13 women), aged from 20 to 58 years, with low bone mineral density (T score < -2) in the spine, total hip, or femur neck were enrolled. Participants were randomly allocated into 2 groups to receive pamidronate or alendronate. The pamidronate group received intravenous pamidronate, 90 mg, starting from the 3rd week of transplantation for 3 months. The alendronate group started to receive oral alendronate, 70 mg per week for the same period. At baseline and 6 months, bone mineral density was measured by dual-energy x-ray absorptiometry. Gastrointestinal side effects were monitored every month. RESULTS: No significant difference was found in bone density changes of the lumber area between the two groups; however, significantly less reduction in bone mineral density of the femur neck and femur occurred in the pamidronate group. Kidney function and parathyroid hormone levels were similar in the two groups before and after the study. Gastrointestinal side effects were seen in 3 patients of the alendronate group only. CONCLUSIONS: Pamidronate was comparable to alendronate in prevention of early bone loss after kidney transplantation.

Evaluation of the patients with syncope during the first month after coronary artery bypass graft.

BACKGROUND: Syncope is a well-known risk factor for adverse cardiovascular event in patients with coronary artery disease, especially those with previous myocardial infarction (MI) or left ventricular dysfunction. The aim of this study was to assess electrophysiologic findings and results of head-up tilt test (HUTT) in patients with syncope and without orthostatic changes in blood pressure during the first month after coronary artery bypass graft (CABG). MATERIALS AND METHODS: A total of 20 patients with syncope during the first month after CABG were prospectively enrolled in this study from June 2002 to April 2006. Electrophysiologic study (EPS) was performed in all of them. HUTT was performed in all of the patients regardless of the result of EPS. RESULTS: The mean age of patients was 60.3±11 years. Twelve patients were males. EPS was negative in 18 patients. HUTT was positive in 10 patients. Six patients had old MI. Ischemic insult occurred in one patient after CABG. Left bundle branch was present in two patients. There was a significant relationship between the duration of bed rest after CABG and positive HUTT (P value = 0.021). All of the patients except one did not experience syncope during the follow-up period. CONCLUSION: In patients with syncope during the first month post CABG, in whom an arrhythmic cause is suspected, the other cause of syncope like orthostatic intolerance should be considered. Being bedridden for an extended period of time post CABG can be a predisposing factor.

QT Dispersion: Does It Change after Percutaneous Coronary Intervention?

BACKGROUND: Myocardial ischemia is one of several causes of prolonged QT dispersion. The aim of this study was to evaluate the effect that percutaneous coronary intervention has on the depolarization and repolarization parameters of surface electrocardiography in patients with chronic stable angina. METHODS: We assessed the effects of full revascularization in patients with chronic stable angina and single-vessel disease who underwent percutaneous coronary intervention. Twelve-lead electrocardiograms were recorded before intervention and 24 hours subsequently. We measured parameters including QRS duration, QT and corrected QT durations, and JT and corrected JT duration in both electrocardiograms and compared the values. RESULTS: There were significant differences between the mean QRS interval (0.086 ± 0.01 sec vs. 0.082 ± 0.01 second; p value = 0.01), mean corrected QT dispersion (0.080 ± 0.04 sec vs. 0.068 ± 0.04 sec; p value = 0.001), and mean corrected JT dispersion (0.074 ± 0.04 sec vs. 0.063 ± 0.04 sec; p value = 0.001) before and after percutaneous coronary intervention. No significant differences were found between the other ECG parameters. CONCLUSION: Our data indicate that the shortening of corrected QT dispersion and corrected JT dispersion in patients undergoing percutaneous coronary intervention is prominent.