Ken Umetani

Twenty-Four Hour Time Domain Heart Rate Variability and Heart Rate: Relations to Age and Gender Over Nine Decades ☆

OBJECTIVESnThis study sought to define the effects of age and gender effects on the normal range of time domain heart rate variability (HRV) over nine decades in healthy subjects.nnnBACKGROUNDnLow HRV is considered an independent marker of mortality risk. However, the age-related decline in HRV may limit its predictive value, particularly in the elderly. Delineation of the range of HRV in healthy subjects over the life span is needed. Gender-related differences in HRV also need clarification.nnnMETHODSnWe determined, according to decade, 24-h heart rate (HR) and HRV of 260 healthy subjects (10 to 99 years old; 112 male, 148 female) by means of five standard time domain measures: standard deviation of all normal sinus RR intervals over 24 h (SDNN), standard deviation of the averaged normal sinus RR intervals for all 5-mm segments (SDANN), mean of the standard deviations of all normal sinus RR intervals for all 5-min segments (SDNN index), root-mean-square of successive normal sinus RR interval difference (rMSSD) and the percentage of successive normal sinus RR intervals >50 ms (pNN50).nnnRESULTSn1) HRV decreased with aging, the pattern of change being measure dependent. HRV (SDNN and SDANN) decreased only very gradually, reaching 60% of baseline (second-decade values) by the tenth decade. With the SDNN index, HRV decreased linearly with aging, reaching 46% of baseline by the tenth decade. Using pNN50 and rMSSD, HRV decreased most rapidly, reaching 24% and 47% of baseline, respectively, by the sixth decade and then stabilized. 2) Using the SDNN index, rMSSD and pNN50, HRV of subjects >65 years old fell below published cutpoints for increased risk of mortality in 25%, 12% and 4%, respectively. 3) At age <30 years, HRV for all measures was lower in female than male subjects. Gender differences decreased at age >30 years and disappeared at age >50 years. 4) HR also declined with aging but much more slowly. HR at age <50 years was faster in female than in male subjects. Gender differences disappeared thereafter.nnnCONCLUSIONSn1) Using all measures, HRV of healthy subjects declines with aging, with measure-dependent patterns. 2) Using the SDNN index, rMSSD and pNN50, HRV of healthy subjects, particularly those >65 years old, may decrease to below levels associated with increased risk of mortality. 3) Gender influences HRV. Gender differences in HRV are age and measure dependent. 4) Age and gender also affect heart rate.

Body Surface Laplacian Mapping in Patients with Left or Right Ventricular Bundle Branch Block

Body surface Laplacian maps (BSLMs) have been previously reported to provide enhanced capability in localizing and resolving multiple spatially separate myocardial events. However, only a few studies have been reported on the clinical applications of BSLM. To test the clinical utility of BSLMs, BSLMs and body surface potential maps (BSPMs) during ventricular depolarization for complete right or left ventricular bundle branch block (CRBBB or CLBBB) were studied in ten patients in each group. As a control group, ten healthy subjects were also studied using the same procedure. One hundred and twenty‐eight electrodes were placed uniformly over the entire chest and back of the subjects. BSLMs were computed from recorded potentials, using a numerical algorithm. The BSLMs showed multiple and more localized positive and negative activities compared with the BSPMs. In healthy subjects, the BSLMs showed multiple areas of positive activity overlying the RV, LV, and the RV outflow, and negative activity corresponding to RV free‐wall breakthrough and LV anterolateral breakthrough sites, whereas the BSPMs could not separate RV and LV activities. In the patients with CRRRR, the BSLMs showed more localized areas of activity corresponding to the LV apex breakthrough and LV lateral breakthrough, and separated LV lateral and posterior activation. In the patients with CLBBB, the BSLMs showed multiple RV activation, and propagating activation of LV from lateral to posterior. The BSLMs appear to provide enhanced capability in detecting multiple ventricular electrical events associated with normal and abnormal conduction and a more detailed activation sequence of both ventricles in healthy subjects and in the patients with CRBBB and CLBBB. BSLM may provide an important alternative to other imaging modalities in localizing cardiac electrical activity noninvasively.

The Inhibitory Effects of Carvedilol Against Arrhythmias Induced by Coronary Reperfusion in Anesthetized Rats

Background: Previous study has shown the antiarrhythmic effects of carvedilol on isolated rat hearts, but little is known about the mechanism of this protective action. This article examines the inhibitory effect of carvedilol against arrhythmias induced by reperfusion in anesthetized rats. In addition, the results are compared with those with propranolol, super oxide dismutase (SOD) plus catalase, and a combination of both in order to elucidate the mechanism of the protective actions. Methods and Materials: Ninety percent of the rats in the control group showed lethal ventricular fibrillation (VF). Carvedilol at the doses of 0.03, 0.1, and 0.3 mg/kg significantly reduced the incidence of lethal VF to 0%, 0%, and 10%, respectively ( P < .05). In contrast, propranolol at the doses of 0.3, 1.0, and 3.0 mg/kg and SOD (35,000 units/kg) plus catalase (400,000 units/kg) did not reduce the incidence of lethal VF (80%, 60%, 70%, and 70%, respectively). However, administration of a combination of propranolol (1.0 mg/kg) and SOD plus catalase completely inhibited the occurrence of lethal VF to 0% ( P < .05). Conclusion: These results indicate that carvedilol has the inhibitory effect against reperfusion arrhythmias in rats and suggest that the mechanism of action of this compound is related to the combined effects of beta-blocking and antioxidant.

Restored atrial excitability after late recanalization in a patient with atrial standstill and acute myocardial infarction.

KOSHIMIZU, T‐A., et al.: Restored Atrial Excitability After Late Recanalization in a Patient with Atrial Standstill and Acute Myocardial Infarction. Atrial standstill is electrophysiologically characterized by the loss of spontaneous excitation in atrial muscle and the inability to cause action potential firing upon electrical stimulation. Clinical diagnosis of transient standstill of the right atrium was made in a patient with acute occlusion of the right coronary artery and acute renal failure. Percutaneous coronary intervention, performed 5 days after the onset, restored the coronary blood flow and resulted in full recovery of electrical activity and regular sinus rhythm.

Improvement of exercise tolerance by single lead VDD pacemaker: evaluation using cardiopulmonary exercise test.

We used a Cardiopulmonary test to assess the physiological benefit of single lead VDD pacing in ten patients (six men, four women; aged 32–84 years, mean 69 years) with atrioventricular block. Maximal symptom‐limited treadmill exercise test using a ramp protocol was performed under VDD and VVIR or VVI pacing (VVI) in random sequence. The pacemaker was then programmed to the VDD mode, and Holter ECG was recorded in nine patients. Compared with findings during the VVI, the VDD mode had a greater chronotropic response (mean maximal heart rate, VDD 106 ± 17 beats/mm vs VVI 79 ± 19 beats/min, P = 0.03), and was associated with prolongation of exercise duration (VDD 11.2 ± 2.9 minute vs VVI 10.5 ± 3.1 minute; P = 0.01), and the onset of anaerobic threshold at a higher oxygen uptake (VDD 12.4 ± 3.4 mL/min per kilogram vs WI 10.0 ± 2.1 mL/min per kilogram; P < 0.01). Atriai sensing was recognized in almost all normal sinus P waves for all cases examined using Holter ECG. Thus, chronotropic response during exercise by VDD pacemaker improved exercise tolerance, indicating that a VDD pacemaker might be useful for patients requiring physical activity.

Pathological findings of the isthmus between the inferior vena cava and tricuspid annulus ablated by radiofrequency application.

Anatomically guided radiofrequency ablation for the treatment of atrial flutter was performed in a 41‐year‐old man with interstitial pneumonia. He died of respiratory failure 2 months after ablation, and an autopsy was performed. The whole layer of the ablation site showed a transluminal fibrosis.

Cardiac Sarcoidosis Presenting as Acute Progressive Heart Failure with Abdominal Lymphadenopathy

A 77-year-old Japanese woman presented with asymptomatic abdominal lymphadenopathy. Soluble interleukin-2 receptor (sIL2R) and angiotensin-converting enzyme (ACE) levels were elevated, and a pathological examination of lymph-node biopsies revealed non-caseating granulomas, which was consistent with sarcoidosis. Fluorodeoxyglucose-positron emission tomography did not show a clear accumulation in the mediastinal lymph-nodes or heart. Five months later, she presented with acute progressive heart failure that was refractory to conventional treatment. Her sIL2R and ACE levels decreased spontaneously over time, without steroid treatment. Autopsy findings revealed non-caseating granulomas. Cardiac sarcoidosis presenting as acute, progressive, treatment-refractory heart failure is rare. Steroid therapy after the resolution of inflammation did not affect the clinical outcome.

Acute myocardial infarction due to simultaneous spasm of 3 coronary arteries that worsened over time

Coronary artery spasm (CAS) rarely worsens from single-vessel to simultaneous multivessel CAS naturally, and simultaneous multivessel CAS leads to serious conditions such as cardiopulmonary arrest (CPA). A 77-year-old Japanese man who took medications for CAS was transferred to our hospital due to persistent chest pain. On arrival, his vital signs were stable, but his electrocardiogram (ECG) showed ST-segment elevation in leads II, III and aVF. Ventricular fibrillation developed suddenly. Although routine cardiopulmonary resuscitation (CPR) including intravenous administration of epinephrine was performed immediately, he could not be resuscitated. After initiation of percutaneous cardiopulmonary support (PCPS), there was a return of spontaneous circulation. His ECG showed exacerbation of myocardial ischemia with ST-segment elevation in leads I, II, III, aVL, aVF and V3-V6. Emergency coronary angiography revealed severe CAS of the right and left coronary arteries, which was relieved completely by intracoronary administration of nitrates. He was diagnosed with acute myocardial infarction due to simultaneous 3-vessel CAS that progressed over time. About 6h after arrival, he developed hemodynamic instability and died. CAS worsened from single-vessel to simultaneous 3-vessel spasm, and intracoronary administration of nitrates was effective in relieving CAS, which was documented by the ECG and coronary angiogram. Since CAS can progress over time, nitrates must be administered immediately. When CAS leads to CPA, epinephrine may be ineffective in CPR because of its vasoconstrictive effect on coronary arteries; therefore, PCPS should be initiated, and intracoronary nitrates should be administered.

A Case of Heart Failure with Paroxysmal Atrial Flutter (pAFL) Ameliorated by Successful Radiofrequency Ablation (RFA)—Improvement of Biventricular Dysfunction by Radionuclide Ventriculography

A 75-year-old man, who had been suffered from hypertrophic cardiomyopathy and ischemic heart disease admitted with non-tachycardia pAFL and heart failure. He was found to have severe biventricular diastolic dysfunction during sinus rhythm by radionuclide ventriculography. Common type 4:1 conduction flutter (rate 240 bpm) was revealed by halo catheter mapping and CARTO mapping of the electrophysiological study. Linear ablations at the isthmus terminated the AFL completely. The AFL could not be induced. No relevant changes were noticed for ventricular rate, and left ventricular (LV) ejection fraction (EF) (changed from 64% to 68%), whereas, right ventricular (RV) EF improved from 42% to 49% during sinus rhythm before and after the RFA by radionuclide ventriculography. Before and after the RFA at normal sinus rhythm, peak filling rate of LV and RV by radionuclide ventriculography increased from 161.4%/s to 204.8%/s, and from 111.1%/s to 174.8%/s, respectively. Diastolic parameters did not changed after the RFA by echocardiography. The RFA of pAFL is considered to improve heart failure symptoms, biventricular diastolic dysfunction, and RV systolic hypo-function. Radionuclide ventriculography appears to be useful for evaluating the therapeutic effects of RFA in patient with pAFL and biventricular dysfunction.