Tachycardia mediated cardiomyopathy: Pathophysiology,mechanisms, clinical features and management

Tachycardia mediated cardiomyopathy (TMC) is a reversible form of dilated cardiomyopathy that can occur with most supraventricular and ventricular arrhythmias. Despite the plethora of literature describing this entity in animal models, as well as humans, it remains poorly understood. Over the last decade, new etiologies of TMC, such as frequent premature ventricular complexes in normal hearts, have been identified. Recent advances in catheter-based ablation therapies, particularly for atrial fibrillation and ventricular arrhythmias, have added a new dimension to the treatment of this condition. This review describes the pathophysiology, proposed mechanisms, clinical features and management in various arrhythmic conditions.     

Eosinophilic myocarditis due to Churg–Strauss syndrome mimicking reversible dilated cardiomyopathy

A 41-year-old woman with a history of asthma arrived at the emergency room of our hospital with dyspnea. The electrocardiogram showed no specific results. Echocardiography defects revealed an obvious decrease in the left ventricular systolic function and enlargement of the left chamber. We initially considered her condition to be dilated cardiomyopathy. However, she had eosinophilia in the peripheral blood and elevated cardiac enzymes. The coronary angiography showed normal coronary arteries. Single photon emission computed tomography (SPECT) showed infiltrative myocardial disease. She was then diagnosed with eosinophil infiltrations. Combined with peripheral nerve injury and lung involvement, she was diagnosed as having Churg–Strauss syndrome. After initiating prednisone treatment, her eosinophilia and rising cardiac enzymes recovered to normal, and both her echocardiographic abnormalities and symptoms noticeably improved.     

Electrocardiographic predictors of sudden and non-sudden cardiac death in patients with ischemic cardiomyopathy

ObjectiveThis study evaluated the prognostic value of electrocardiogram (ECG)-based predictors in the primary prevention of sudden cardiac arrest (SCA) among ischemic cardiomyopathy patients with depressed left ventricular ejection fraction (LVEF ≤35%).BackgroundThe prediction of cause-specific mortality in high-risk patients offers the potential for targeting specific therapies (i.e., implantable cardioverter-defibrillator [ICD]).MethodsSubjects were recruited from the Prediction of Arrhythmic Events with Positron Emission Tomography (PAREPET) study. Continuous Holter 12-lead ECG recordings were obtained at the start of study and used to compute 15 clinically-important ECG abnormalities (e.g., atrial fibrillation).ResultsAmong 197 patients (age 67 ± 11 years, 93% male, mean follow-up 4.1 years) enrolled, 30 (15%) were SCA cases and 35 (18%) cardiac non-sudden deaths (C/NS). In multivariate analysis, only heart-rate-corrected QT interval (QTc) predicted SCA (hazard ratio 2.9 [1.2–7.3]) and only depressed heart rate variability (HRV) predicted C/NS (hazard ratio 5.0 [1.5–17.1]) independent of demographic and clinical parameters.ConclusionsAmong patients with depressed LVEF, prolonged QTc suggests greater potential benefit from ICD therapy to prevent SCA; depressed HRV suggests potential benefit from bi-ventricular pacing to prevent C/NS.     

Growth differentiation factor-15 in Takotsubo cardiomyopathy: Diagnostic and prognostic value

Background

Growth differentiation factor-15 (GDF-15), a stress responsive cytokine, has emerged as a marker of adverse outcome in various cardiovascular diseases. Since GDF-15 has not been evaluated in patients with Takotsubo cardiomyopathy (TTC), the present study sought to investigate the diagnostic and prognostic value in this patient cohort.

Methods

A total of 22 patients presenting with TTC were matched for age and gender with 22 ST-segment elevation myocardial infarction (STEMI) patients. GDF-15 concentrations were measured at admission and 1 day thereafter. The primary clinical endpoint of the TTC cohort was the composite of death, cardiogenic shock, or new congestive heart failure within 6 months.

Results

TTC patients showed significantly higher GDF-15 values on admission compared to patients presenting with STEMI (median 3047 ng/l [interquartile range 2256–7572] versus median 1527 ng/l [interquartile range 1152–2677]; p = 0.002). TTC patients with a biventricular ballooning pattern and patients experiencing major adverse cardiac events during the first 6 months after acute presentation showed significantly higher GDF-15 concentrations on admission (p = 0.008 and p = 0.005, respectively). Biventricular ballooning was identified as a predictor for elevated GDF-15 values on admission (p = 0.03). High GDF-15 levels on admission were the only significant predictor for the combined clinical endpoint in multivariable regression analysis (p = 0.02).

Conclusion

TTC patients showed markedly high, but transient elevation of GDF-15 levels. Biventricular ballooning was associated with particularly high GDF-15 concentrations. Elevated GDF-15 values on admission were a strong predictor of adverse clinical outcome.     

Complications in the clinical course of tako-tsubo cardiomyopathy

Objective

This study evaluated the frequency, severity and outcome of complications in the clinical course of tako-tsubo cardiomyopathy (TTC).

Background

TTC is regarded as a benign disease since left ventricular (LV) function returns to normal within a short time. However, severe complications have been reported in selected patients.

Methods

From 37 hospitals, 209 patients (189 female, age 69 ± 12 years) were prospectively included in a TTC registry.

Results

Complications developed in 108/209 patients (52%); 23 (11%) had > 2 complications. Complications occurred median 1 day after symptom onset, and 77% were seen within 3 days. Arrhythmias were documented in 45/209 patients (22%) including atrial fibrillation in 32 (15%) and ventricular tachycardia in 17 (8%). Of 8 patients resuscitated (4%), 6 survived. Additional complications were right ventricular involvement (24%), pulmonary edema (13%), cardiogenic shock (7%), transient intraventricular pressure gradients (5%), LV thrombi (3%) and stroke (1%). During hospitalization, 5/209 patients (2.5%) died. Patients with complications were older (70 ± 13 vs 67 ± 10 years, p = 0.012), had a higher heart rate (91 ± 26 vs 83 ± 19/min, p = 0.025), more frequently Q\ waves on the admission ECG (36% vs 21%, p = 0.019) and a lower LV ejection fraction (47 ± 15 vs 54 ± 14%, p = 0.002). Multivariate regression analysis identified Q-waves on admission (OR 2.49, 95% CI 1.23–5.05, p = 0.021) and ejection fraction ≤ 30% (OR 4.03, 95% CI 1.04–15.67, p = 0.022) as independent predictors for complications.

Conclusions

TTC may be associated with severe complications in half of the patients. Since the majority of complications occur up to day 3, monitoring is advisable for this time period.     

硝酸甘油外敷治疗糖尿病母亲新生儿动脉栓塞引起的缺血坏死

目的 采用安全、温和的治疗方法缓解患动脉栓塞的糖尿病母亲新生儿局部缺血坏死的症状,降低患者截肢和死亡的风险。方法 在低分子肝素抗凝的基础上,加用硝酸甘油局部外敷治疗。结果 患儿左前臂和左手的缺血性改变逐渐消失,手部的功能基本得以保存,未见明显不良反应。结论 硝酸甘油外敷对于新生儿动脉栓塞引起的缺血坏死可能有一定的缓解作用。     

Strategies for assessing the prevalence of cardiovascular sudden deaths in young competitive athletes

Background/Objectives

Prevalence/incidence of sudden death due to cardiovascular disease in young competitive athletes has become an important part of the debate over the most effective and practical preparticipation screening strategies for this population. Since event reporting is not mandatory, identification of cases has been achieved largely through publicly available data and internet searches. The accuracy of this methodology has not been studied and deserves scrutiny.

Methods

We assessed recognition of sudden cardiovascular deaths in college (NCAA) athletes with the U.S. National Registry of Sudden Death in Athletes that uses largely public domain sources, and also the NCAA Memorial Resolutions List.

Results

For 2002–2011, 64 total sudden death cases were identified by both sources. The Registry identified 56 cases (88%), including 14 not found in the NCAA List. The NCAA List identified 50 cases (78%), including 8 unrecognized by the Registry (p = 0.16). Failure to initially recognize these 8 deaths using established Registry search mechanisms was due to the absence of key search terms in media reports. Cases not identified by the 2 methodologies did not differ significantly regarding demographics, cause of death, or sport.

Conclusions

Internet-based, public domain methodology is useful and identified more cases of sudden cardiovascular death in college athletes than did the internal list provided by the NCAA. Nevertheless, these findings support the principle that multiple sources are additive and beneficial in identifying the maximum number of sudden death events.