Postural orthostatic tachycardia syndrome is associated with platelet storage pool deficiency

Mechanisms have been postulated to explain postural orthostatic tachycardia syndrome (POTS), however, the etiology of this often debilitating disorder remains unknown. We conducted a retrospective case-control study of 181 POTS patients who exhibited/reported bleeding symptoms for a specific platelet (PL) dysfunction disorder, delta granule storage pool deficiency (δ-SPD).Patients were included only if results of blood tests for δ-SPD were available. Electron microscopy was utilized to diagnose δ-SPD. An ELISA assay was used to determine serotonin (5HT) concentration in PLs and medical record review was employed to collect patients' clinical symptoms.The most common bleeding symptom was easy bruising (71%) but frequent nose bleeds, heavy menstrual bleeding, and a family history of bleeding were also commonly reported. Of the patients studied, 81% were diagnosed with δ-SPD. Our investigation of 5HT concentration extracted from PLs revealed significantly lower levels of 5HT in POTS patients when compared to that of control subjects. Our data suggest that patients with POTS have significant comorbidities including bleeding symptoms and/or family bleeding histories, and have diminished PL 5HT levels supporting the hypothesis that POTS is a low 5HT level disorder. While we describe a significant relationship with POTS and δ-SPD, this finding does not constitute an etiology for POTS.Our results establish an additional comorbidity frequently seen in POTS that could explain a number of disparate symptoms often affecting the severity of POTS.

Utility of High-Output His Pacing during Difficult AV Node Ablation. An Underutilized Strategy

Atrioventricular (AV) node ablation is a commonly performed procedure for patients with chronic drug refractory atrial fibrillation (AF) with episodes of rapid ventricular response. We report on a 72-year-old man who had difficulty managing chronic drug refractory AFs with frequent hospitalizations for rapid ventricular rate. The patient was taken to the electrophysiology laboratory for AV node ablation. Extensive mapping and localization techniques of the compact AV node and ablation in the region were unsuccessful. Subsequently, high-output His bundle pacing using 20 mA at 2 ms of output energy was performed in an attempt to localize the His bundle in areas where high-output pacing resulted in a narrower QRS complex. Further ablations in the areas where pacing produced a narrower QRS complex resulted in complete heart block. This case highlights the importance of using this simple pacing maneuver to achieve complete heart block in patients in whom standard strategies to localize and ablate the compact AV node are unsuccessful.

Orthostatic hypotension: definition, diagnosis and management

Orthostatic hypotension commonly affects elderly patients and those suffering from diabetes mellitus and Parkinson's disease. It is a cause of significant morbidity in the affected patients. The goal of this review is to outline the pathophysiology, evaluation, and management of the patients suffering from orthostatic hypotension.

Rituximab induced left bundle branch block

Rituximab (a monoclonal antibody directed against CD 20) therapy can be acutely complicated by infusion reactions and cardiac arrhythmia on rare occasions. We report the first case of a new onset left bundle branch block (LBBB) after rituximab therapy for Wegener's vasculitis.

Recurrent myocardial infarctions in a young football player secondary to thrombophilia, associated with elevated factor VIII activity

Myocardial infarction (MI) due to coronary atherosclerosis in young adults is uncommon; rare causes such as cocaine abuse, arterial dissection, and thromboembolism should be considered. A 21-year-old football player, and otherwise healthy African American man, developed chest pain during exercise while bench-pressing 400 lbs. Acute MI was diagnosed based on physical examination, electrocardiography findings, and elevated cardiac enzymes. Coronary arteriography showed a thrombus occluding the proximal left anterior descending artery (LAD). Aggressive antiplatelet therapy with aspirin, clopidogrel, and eptifibatide was pursued, in addition to standard post-MI care. This led to the successful resolution of symptoms and dissolution of the thrombus, demonstrated by repeat coronary arteriography. Five months later, he presented with similar symptoms during exercise after lifting heavy weights, and was found to have another acute MI. Coronary arteriography again showed a thrombus occluding the LAD. No evidence of coronary artery dissection or vasospasm was found. Only mild atherosclerotic plaque burden was observed on both occasions by intravascular ultrasound. A bare metal stent was placed at the site as it was thought this site had acted as a nidus for small plaque rupture and thrombus formation. Elevated serum factor VIII activity at 205% (reference range 60%–140%) was found, a rare cause of hypercoagulability. Further workup revealed a patent foramen ovale during a Valsalva maneuver by transesophageal echocardiography. Both events occurred during weight lifting, which can transiently increase right heart pressure in a similar way to the Valsalva maneuver. In light of all the findings, we concluded that an exercise-related increase in factor VIII activity led to coronary arterial thrombosis in the presence of a small ruptured plaque. Alternatively, venous clots may have traversed the patent foramen ovale and occluded the LAD. In addition to continuing aggressive risk factor modification, anticoagulation therapy with warfarin was initiated with close follow-up.

Syncope in the athlete

Syncope in the athlete requires a complete evaluation, as this may be the only warning prior to an episode of sudden cardiac death. This should include a detailed history which includes specific details of the event as well as bystander descriptions when possible. Following the history should be a careful physical examination and subsequent diagnostic testing based on the individual's needs. The purpose of the evaluation is to determine if structural or electrical heart disease is present that may lead to sudden death. If absent, the patient, family and staff can be reassured that it is safe to resume athletic activity. Careful attention to the athlete with syncope may both prevent potential disasters in some, while at the same time enjoyment of intense physical activity in others.

Clinical presentation and management of patients with hyperadrenergic postural orthostatic tachycardia syndrome. A single center experience

BACKGROUND

We present our single center experience of 27 patients of hyperadrenergic postural orthostatic tachycardia syndrome (POTS).

METHODS

In a retrospective analysis, we reviewed the charts of 300 POTS patients being followed at our autonomic center from 2003 to 2010, and found 27 patients eligible for inclusion in this study. POTS was defined as symptoms of orthostatic intolerance (of greater than six months' duration) accompanied by a heart rate increase of at least 30 bpm (or a rate that exceeds 120 bpm) that occurs in the first 10 min of upright posture or head up tilt test (HUTT) occurring in the absence of other chronic debilitating disorders. Patients were diagnosed as having the hyperadrenergic form based on an increase in their systolic blood pressure of ≥ 10 mm Hg during the HUTT (2) with concomitant tachycardia or their serum catecholamine levels (serum norepinephnrine level ≥ 600 pg/mL) upon standing.

RESULTS

Twenty seven patients, aged 39 ± 11 years, 24, (89%) of them female and 22 (82%) Caucasian were included in this study. Most of these patients were refractory to most of the first and second line treatments, and all were on multiple combinations of medications.

CONCLUSIONS

Hyperadrenergic POTS should be identified and differentiated from neuropathic POTS. These patients are usually difficult to treat and there are no standardized treatment protocols known at this time for patients with hyperadrenergic POTS.

Post-reperfusion syndrome during renal transplantation: a retrospective study

Post-reperfusion syndrome (PRS) is a serious, widely reported complication following the reperfusion of an ischemic tissue or organ. We sought to determine the prevalence, risk factors and short-term outcomes of PRS related renal transplantation. We conducted a retrospective, case-control study of patients undergoing renal transplantation between July 2006 and March 2008. Identification of PRS was based on a drop in mean arterial pressure by at least 15% within 5 minutes of donor kidney reperfusion. Of the 150 consecutive renal transplantations reviewed, 6 patients (4%) met criteria for post-reperfusion syndrome. Univariate analysis showed that an age over 60, diabetes mellitus, Asian race, and extended criteria donors increased the odds of developing PRS by 4.8 times (95% CI [1.2, 20]; P=.0338), 4.5 times (95% CI [1.11, 18.8]; P=.0378), 35.5 times (95% CI [3.94, 319.8]; P=0.0078) and 9.6 times (95% CI [1.19, 76.28] P=0.0115) respectively. Short term follow-up revealed increased graft failure rate within 6 months (6% vs. 16% P=0.0125) and almost twice the number of hospital days post-transplant in PRS cohorts (5.43 ± 2.29 vs. 10.8 ± 7.29 P=<0.0001). Despite limited reporting, PRS appears to be a relatively common complication of renal transplantation and is associated with increase morbidity.

Autonomic dysfunction presenting as orthostatic intolerance in patients suffering from mitochondrial cytopathy

BACKGROUND

Disturbances in autonomic nervous system function have been reported to occur in patients suffering from mitochondrial cytopathies. However, there is paucity of literature on the occurrence of orthostatic intolerance (OI) in these patients. We report on a series of patients diagnosed with mitochondrial cytopathy who developed features of autonomic dysfunction in the form of OI.

METHODS

This was a single-center report on a series of 6 patients who were followed in our clinic for orthostatic intolerance. All of these patients had a diagnosis of mitochondrial cytopathy on the basis of muscle biopsy and were being followed at a center specializing in the treatment of mitochondrial disorders. This study was approved by our local institutional review board. Each of the patients had suffered from symptoms of fatigue, palpitations, near syncope, and syncope. The diagnosis of OI was confirmed by head-up tilt test. Collected data included demographic information, presenting symptoms, laboratory data, tilt-table response, and treatment outcomes.

RESULTS

Six patients (3 females) were identified for inclusion in this report. The mean age of the group was 48 ± 8 years (range, 40-60 years). All of these patients underwent head-up tilt table testing and all had a positive response that reproduced their clinical symptoms. Among those having an abnormal tilt-table pattern, 1 had a neurocardiogenic response, 1 had a dysautonomic response, and 4 had a postural orthostatic tachycardia response. All but 1 patient reported marked symptom relief with pharmacotherapy. The patient who failed pharmacotherapy received a dual-chamber closed-loop pacemaker and subsequently reported marked improvement in her symptoms with elimination of her syncope.

CONCLUSIONS

Orthostatic intolerance might be a significant feature of autonomic nervous system dysfunction in patients suffering from mitochondrial cytopathy.

Postural orthostatic tachycardia syndrome following Lyme disease

BACKGROUND

A subgroup of patients suffering from Lyme disease (LD) may initially respond to antibiotics only to later develop a syndrome of fatigue, joint pain and cognitive dysfunction referred to as 'post treatment LD syndrome'. We report on a series of patients who developed autonomic dysfunction in the form of postural orthostatic tachycardia syndrome (POTS).

METHODS

All of the patients in this report had suffered from LD in the past and were successfully treated with antibiotics. All patients were apparently well, until years later when they presented with fatigue, cognitive dysfunction and orthostatic intolerance. These patients were diagnosed with POTS on the basis of clinical features and results of the tilt table (HUTT) testing.

RESULTS

Five patients (all women), aged 22-44 years, were identified for inclusion in this study. These patients developed symptoms of fatigue, cognitive dysfunction, orthostatic palpitations and either near syncope or frank syncope. The debilitating nature of these symptoms had resulted in lost of the employment or inability to attend school. Three patients were also suffering from migraine, two from anxiety and depression and one from hypertension. All patients demonstrated a good response to the employed treatment. Four of the five were able to engage in their activities of daily living and either resumed employment or returned to school.

CONCLUSIONS

In an appropriate clinical setting, evaluation for POTS in patients suffering from post LD syndrome may lead to early recognition and treatment, with subsequent improvement in symptoms of orthostatic intolerance.

A case of mistaken identity: asystole causing convulsions identified using implantable loop recorder

We present herein an interesting tracing of a patient who suffered from recurrent episodes of transient loss of consciousness (TLOC) associated with convulsive activity thought to be due to epilepsy or conversion disorder.

Neurocardiogenic syncope: mechanisms, evaluation and treatment

Syncope is the abrupt and transient loss of consciousness due to a temporary reduction in cerebral blood flow, associated with an absence of postural tone, followed by a rapid and usually complete recovery. It may result from several possible etiologies, ranging from the benign to the potentially fatal. Neurocardiogenic (vasovagal) syncope is the most common of a group of neurally mediated syncopes, characterized by a sudden failure of autonomic regulatory mechanisms to maintain adequate blood pressure and, occasionally, heart rate, to sustain cerebral perfusion and consciousness. The diagnosis may be suggested by a characteristic history and by exclusion of other causes of syncope; however, in some cases, upright tilt table testing may be required to provoke typical hemodynamic responses. Cardiologists and cardiac electrophysiologists are frequently expected to manage patients with suspected neurocardiogenic syncope. The following review aims to provide a basic framework for understanding its pathophysiology, clinical presentations, diagnosis and treatment.

Comparative clinical profile of postural orthostatic tachycardia patients with and without joint hypermobility syndrome

BACKGROUND

Autonomic dysfunction is common in patients with the joint hypermobility syndrome (JHS). However, there is a paucity of reported data on clinical features of Postural orthostatic tachycardia syndrome (POTS) in patients suffering from JHS.

METHODS

This retrospective study was approved by our local Institutional Review Board (IRB). Over a period of 10 years, 26 patients of POTS were identified for inclusion in this study. All these patients had features of Joint Hypermobility Syndrome (by Brighton criterion). A comparison group of 39 patients with other forms of POTS were also followed in the autonomic clinic during the same time. We present a descriptive report on the comparative clinical profile of the clinical features of Postural Orthostatic Tachycardia patients with and without Joint Hypermobility syndrome. The data is presented as a mean+/-SD and percentages wherever applicable.

RESULTS

Out of 65 patients, 26 patients (all females, 20 Caucasians) had POTS and JHS. The mean age at presentation of POTS was 24+/-13 (range 10-53 years) vs 41+/-12 (range 19-65 years), P=0.0001, Migraine was a common co morbidity 73 vs 29% p=0,001. In two patients POTS was precipitated by pregnancy, and in three by surgery, urinary tract infection and a viral syndrome respectively. The common clinical features were fatigue (58%), orthostatic palpitations (54%), presyncope (58%), and syncope (62%).

CONCLUSIONS

Patients with POTS and JHS appear to become symptomatic at an earlier age compared to POTS patients without JHS. In addition patients with JHS had a greater incidence of migraine and syncope than their non JHS counterparts.

Autonomic dysfunction presenting as postural orthostatic tachycardia syndrome in patients with multiple sclerosis

BACKGROUND

Autonomic dysfunction is common in patients suffering from multiple sclerosis (MS) and orthostatic dizziness occurs in almost 50% of these patients. However, there have been no reports on postural orthostatic tachycardia syndrome (POTS) in patients suffering from MS.

METHODS

The patients were included for analysis in this study if they had POTS with either a prior history of MS or having developed MS while being followed for POTS. Postural orthostatic tachycardia (POTS) is defined as symptoms of orthostatic intolerance(>6 months) accompanied by a heart rate increase of at least 30 beats/min (or a rate that exceeds 120 beats/min) that occurs in the first 10 minutes of upright posture or head up tilt test (HUTT) occurring in the absence of other chronic debilitating disorders. We identified nine patients with POTS who were suffering from MS as well. Each of these patients had been referred from various other centers for second opinions.

RESULTS

The mean age at the time of diagnosis of POTS was 49+/-9 years and eight of the 9 patients were women. Five patients (55%) had hyperlipidemia, 3 (33%) migraine and 2 (22%) patients had coronary artery disease and diabetes each. Fatigue and palpitations (on assuming upright posture) were the most common finding in our patients (9/9). All patients also had orthostatic dizziness. Syncope was seen in 5/9(55%) of patients. Four patients (44%), who did not have clear syncope, were having episodes of near syncope. The presence of POTS in our study population resulted in substantial limitation of daily activities. Following recognition and treatment of POTS, 6/9(66%), patients were able to resume daily activities of living. Their symptoms (especially fatigue and orthostatic intolerance) improved. The frequency and severity of syncope also improved. Three (33%) patients failed to show a good response to treatment.

CONCLUSION

Patients suffering from MS may manifest autonomic dysfunction by developing POTS. Early recognition and proper management may help improve the symptoms of POTS.

A tale of two atria

We present an interesting intracardiac electrogram of a dissimilar atrial rhythm in a patient of bi-atrial orthotopic cardiac transplant.

Autonomic dysfunction presenting as postural tachycardia syndrome following traumatic brain injury

BACKGROUND

Autonomic dysregulation (also called diencephalic epilepsy) has been reported following traumatic brain injuries (TBI). However, until now, postural tachycardia syndrome (POTS) has not been reported as a long-term complication in patients who have suffered a TBI. We report on a series of patients who developed POTS after suffering TBI.

METHODS

Eight patients who were referred to our center had suffered TBI and developed features of orthostatic intolerance following head trauma. The patients' neurological, neurosurgical and autonomic data (charts and/or physician letters) were then carefully reviewed for demographic characteristics, comorbid conditions, symptoms of orthostatic intolerance, medications and response to medication. These patients were diagnosed as having POTS, primarily based on their clinical features and findings from the head-up tilt test (HUTT). The data presented is observational and descriptive (percentages or means).

RESULTS

Eight patients (seven of them women) aged 21-41 years had suffered from TBI and had developed features of POTS. All had been normal with no symptoms prior to their TBI. All patients experienced orthostatic dizziness, fatigue, palpitations and near syncope. Six patients suffered from frank syncope. Six patients developed significant cognitive dysfunction, and three developed a chronic pain syndrome following trauma. All of the patients reported severe limitations to their daily activities and had been unable to keep their jobs, and two were housebound. Six patients demonstrated a good response to therapy with various combinations of medication. The symptoms of orthostatic intolerance and syncope improved with the initiation of medical therapy, as well as their reported quality of life. Two patients failed to show any improvement with various combinations of medications and tilt training, and continued to experience orthostatic difficulties.

CONCLUSIONS

Postural tachycardia syndrome may, in some cases, be a late complication of traumatic brain injury.

Outcomes of pregnancy in patients with preexisting postural tachycardia syndrome

BACKGROUND

Postural orthostatic tachycardia syndrome (POTS) occurs more commonly in women than in men and often affects women of childbearing age. Many of these women wish to have children, yet there are little reported data on the outcomes of pregnancy in patients with POTS. To date there has been one report of two patients with POTS who successfully completed pregnancy. We report the outcomes of 22 women with preexisting POTS who became pregnant.

OBJECTIVE

To assess the outcome of pregnancy in patients with preexisting POTS.

METHODS AND RESULTS

Twenty-two patients, age 30 +/- 7 years, with POTS became pregnant. Migraine was the common comorbidity found in 40% of patients. Medications used were beta-blockers (18%), midiodrine (31%), selective serotonin reuptake inhibitors (31%), fludrocortisone (13%), combination (40%), and none (18%). During pregnancy, symptoms of POTS remained unchanged in three (13%), improved in 12 (55%), and worsened in seven (31%) patients. One patient who had recurrent episodes of syncope without aura was found to have complete heart block and received a cardiac pacemaker. All patients completed pregnancy successfully. There were no stillbirths. One patient developed hyperemesis. Eighteen patients had vaginal delivery and four patients delivered by cesarian section. No other complications of pregnancy were encountered. Congenital abnormalities were encountered in the form of one atrial septal defect, one ventricular septal defect, and one Down's syndrome. Postpartum symptoms of POTS remained stable in 15 (69%) patients and worsened in seven (31%) patients.

CONCLUSION

Based on our observation, patients with POTS can safely complete pregnancy if they desire to do so. POTS should not be considered a contraindication to pregnancy per se.